PowlVac Type PVDST Replacement Vacuum Circuit Breaker Replacement for Federal Pacific Type DST Air-Magnetic Circuit Breakers

Transcription

1 Instructions IB PowlVac Type PVDST Replacement Vacuum Circuit Breaker Replacement for Federal Pacific Type DST Air-Magnetic Circuit Breakers Installation Maintenance Renewal Parts POWELL ELECTRICAL MANUFACTURING COMPANY 8550 MOSLEY DRIVE HOUSTON, TEXAS USA PHONE (713) FAX (713) POWELL ELECTRICAL MANUFACTURING CO. All Rights Reserved.

2 IB PowlVac Type PVDST Circuit Breaker WARNING THIS EQUIPMENT MAY CONTAIN HIGH VOLTAGES AND CURRENTS WHICH CAN CAUSE SERIOUS INJURY OR DEATH. IT IS DESIGNED FOR USE, INSTALLATION, AND MAINTENANCE BY KNOWLEDGABLE USERS OF SUCH EQUIPMENT HAVING EXPERIENCE AND TRAINING IN THE FIELD OF HIGH VOLTAGE ELECTRICITY. THIS DOCUMENT, AND ALL OTHER DOCUMENTATION, SHOULD BE FULLY READ AND UNDERSTOOD AND ALL WARNINGS AND CAUTIONS ABIDED BY. IF THERE ARE ANY DISCREPANCIES OR QUESTIONS, THE USER SHOULD CONTACT POWELL ELECTRICAL MANUFACTURING COMPANY IMMEDIATELY AT CAUTION Before any adjustments, servicing, parts replacement, or any other act is performed requiring physical contact with the electrical working components or wiring of this equipment, the POWER SUPPLY MUST BE DISCONNECTED AND THE CIRCUIT BREAKER CLOSING SPRING MUST BE DISCHARGED.

3 PowlVac Type PVDST Circuit Breaker IB Table of Contents 1 I. INTRODUCTION... 5 A. SCOPE... 5 B. PURPOSE... 5 C. CONFLICT WITH OTHER DOCUMENTS... 5 D. OTHER ITEMS OF CAUTION... 5 E. INSTRUCTION BULLETINS ON THE WEB... 6 II. SAFETY... 6 A. GENERAL... 6 B. SPECIFIC... 7 C. X-RAYS... 7 D. SAFETY LABELS... 8 III. DESCRIPTION... 9 A. GENERAL... 9 B. THE STORED ENERGY MECHANISM... 9 C. ROLLOUT TRUCK D. SECONDARY CONTACTS E. GROUND CONTACT F. LEVERING-IN DEVICE G. SHUTTER LIFT H. INTERLOCKING Levering-in Interlock Cell Interlocks I. OPERATING SOLENOIDS J. MOTOR CUTOFF SWITCH K. VACUUM INTERRUPTERS L. CONTROL CIRCUIT M. ANTI-PUMP RELAY IV. INSTALLATION A. RECEIVING B. HANDLING C. STORAGE D. PUTTING INTO SERVICE Commissioning High Voltage Insulation Integrity Vacuum Integrity Control Voltage Insulation Integrity Mechanical Operation Check Electrical Operation Check Dimensional Check E. INSERTING CIRCUIT BREAKER INTO SWITCHGEAR EQUIPMENT V. MAINTENANCE A. GENERAL Introduction Inspection and Cleaning B. MECHANISM AREA Mechanical Operation Lubrication Closing Spring Removal and Slow Closing of Mechanism POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 3

4 IB PowlVac Type PVDST Circuit Breaker Table of Contents 4. Mechanism Adjustments a. Adjustment of Ratchet Wheel Holding Pawl b. Adjustment of Primary and Secondary Trip Latches and Latch Check Switch c. Adjustment of Close Latch Electrical Operation C. VACUUM INTERRUPTER AND CONTACT AREA Vacuum Interrupter Contact Erosion Sliding Contact Finger Wear Vacuum Integrity D. OPTIONAL MAINTENANCE PROCEDURES High Potential Tests Primary Resistance Check VI. RECOMMENDED RENEWAL PARTS AND REPAIR PROCEDURES A. ORDERING INSTRUCTIONS B. RECOMMENDED RENEWAL PARTS C. REPLACEMENT PROCEDURES VII. ANNEX A. COMMISSIONING FOR REPLACEMENT CIRCUIT BREAKERS Illustrations 1 Figure 1. Exterior Components Figure 2. Cam and Fundamental Linkage Positions Figure 3. Mechanism and Trip Linkages Figure 4. Interior Components Figure 5. Levering-in Device and Cell Interlocks Figure 6. Levering-in Interlock Figure 7. Typical DC Control Scheme Figure 8. Operation Sequence Figure 9. Main Closing Spring Assembly Compressed for Removal Figure 10. Main Closing Spring Assembly Installed Figure 11. Primary Trip Latch Adjusting Screw Figure 12. Lubrication Figure 12. Lubrication Tables 1 Table I. Lubrication Table II. Vacuum Interrupter and Sliding Contact Finger Assemblies Table III. Control Devices Table IV. Miscellaneous Parts Table IV. Miscellaneous Parts Table V. Trouble Shooting Topics POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA

5 PowlVac Type PVDST Circuit Breaker IB These instructions do not purport to cover all details or variations of the circuit breakers nor to provide for every possible contingency or hazard to be met in connection with installation, testing, operation and maintenance. Should further information be desired or should particular problems arise which are not covered sufficiently for the user s purposes, the matter should be referred to Powell Electrical Manufacturing Company or call I. INTRODUCTION A. SCOPE This instruction bulletin describes the following PowlVac Type PVDST Vacuum Circuit Breakers: Type 15PV36DST (750MVA) B. PURPOSE This instruction bulletin provides: 1. Guidelines for safety. 2. A general description of the operation and maintenance of the circuit breakers. 3. Instructions for installation and placing the circuit breakers into service. 4. Instructions for part replacement. 5. Lists of renewal parts. 6. Procedures for critical adjustments. 7. Illustrations, photographs, and descriptions of the circuit breakers. C. CONFLICT WITH OTHER DOCUMENTS This instruction bulletin is intended to assist the operator in the safety, use, installation, operation, and maintenance of the PowlVac Type PVDST Vacuum Circuit Breaker. This instruction bulletin covers the design commonalities of the PowlVac Vacuum Circuit Breaker, and should be used in conjunction with applicable supplements pertaining to the specific type of circuit breaker purchased. The specific type supplement for the circuit breaker along with this instruction bulletin must be studied and understood in order to become fully acquainted with the circuit breaker. If a conflict exists between this instruction bulletin and any other document relating to safety, use, description, installation, illustration, maintenance, renewal parts, and procedure, THIS INSTRUCTION BULLETIN SHALL TAKE PRECEDENCE. THE ONLY EXCEPTION TO THIS IS A SERVICE ADVISORY, A REVISION, OR AN ADDENDUM TO THIS DOCUMENT ISSUED BY POWELL ELECTRICAL MANUFACTURING COMPANY. D. OTHER ITEMS OF CAUTION It should be noted that some illustrations contained herein may not represent the construction details of each user s particular type, but are general illustrations showing component locations. To the extent required, the products described herein meet all applicable ANSI, IEEE, and NEMA standards; but no assurance is given with respect to local codes and ordinances because they vary greatly. Before unpacking the circuit breakers, study this instruction bulletin and all other associated documentation. Follow the recommended procedure for putting into service. POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 5

6 IB PowlVac Type PVDST Circuit Breaker E. INSTRUCTION BULLETINS ON THE WEB Powell Electrical Manufacturing Company Instruction Bulletins are posted on the company website at The instruction bulletins are designed to provide our customers with technical information about our product and the recommended servicing, maintenance, and renewal parts. II. For more information, please contact Powell Apparatus Service Division at , , or SAFETY Each user has the responsibility to instruct and supervise all personnel associated with the installation, operation, and maintenance of this equipment on all safety procedures which must be observed. Furthermore, each user has the responsibility of devising a complete safety program for each type or class of equipment encountered. The circuit breakers described in this instruction bulletin are operated by high energy, and high speed mechanisms interlocked to provide a particular operating sequences. To insure the safety of personnel associated with installation, operation and maintenance of these circuit breakers, it is important that the following rules should be observed. These rules are not intended to be a complete safety program, or to take the place of the user s complete safety program. They are rather rules to cover the more important aspects of personnel safety related to PowlVac circuit breakers. A. GENERAL 1. Only supervised and qualified personnel trained in the use, installation, operation, and maintenance of power circuit breakers should be allowed to work on this equipment. It is important that all instruction bulletins, supplements, and service advisories be studied, understood, and followed. 2. Maintenance programs must be consistent with both customer experience and manufacturer s recommendations including service advisories and instruction bulletins. A well-planned and executed routine maintenance program is essential for circuit breaker reliability and safety. 3. Service conditions and circuit breaker applications must be considered in the development of such programs, including such variables as ambient temperature, actual continuous current, thermal and cycling, number of operations, interrupting duty, and unusual local conditions such as excessive dust, ash, corrosive atmosphere, vermin, or insect problems. 6 POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA

7 PowlVac Type PVDST Circuit Breaker IB B. SPECIFIC 1. DO NOT WORK ON AN ENERGIZED CIRCUIT BREAKER. IF WORK MUST BE PERFORMED ON A CIRCUIT BREAKER, REMOVE IT FROM SERVICE AND REMOVE IT FROM THE METAL-CLAD ENCLOSURE. 2. DO NOT WORK ON A CIRCUIT BREAKER WITH THE CONTROL POWER ENERGIZED. 3. THESE CIRCUIT BREAKERS UTILIZE STORED ENERGY-SPRING CHARGED MECHANISMS. THESE MECHANISMS MUST BE SERVICED ONLY BY SKILLED AND KNOWLEDGEABLE PER- SONNEL CAPABLE OF RELEASING EACH SPRING LOAD IN A CONTROLLED MANNER. EXTREME CARE MUST BE EXERCISED TO KEEP ALL PERSONNEL, TOOLS, AND OTHER OBJECTS CLEAR OF MECHANISMS, WHICH ARE TO BE OPERATED OR RELEASED. DETAILED INFORMATION REGARDING THESE MECHANISMS IS FOUND IN THIS INSTRUCTION BULLETIN. 4. DO NOT ATTEMPT TO CLOSE THE CIRCUIT BREAKER MANUALLY ON A LIVE CIRCUIT. 5. DO NOT USE AN OPEN CIRCUIT BREAKER BY ITSELF AS THE SOLE MEANS OF ISOLATING A HIGH VOLTAGE CIRCUIT. FOR COMPLETE ISOLATION, THE CIRCUIT BREAKER SHOULD BE IN THE DISCONNECTED POSITION. 6. FOR THE SAFETY OF PERSONNEL PERFORMING MAINTENANCE OPERATIONS ON THE BREAKER OR CONNECTED EQUIPMENT, ALL COMPONENTS SHOULD BE DISCONNECTED BY MEANS OF A VISIBLE BREAK AND SECURELY GROUNDED. 7. INTERLOCKS ARE PROVIDED TO ENSURE PROPER OPERATING SEQUENCES OF THE CIRCUIT BREAKER AND FOR THE SAFETY OF THE OPERATOR. IF FOR ANY REASON AN INTERLOCK DOES NOT FUNCTION AS DESCRIBED, DO NOT MAKE ANY ADJUSTMENTS, MODIFICATION, OR DEFORM THE PARTS. DO NOT FORCE THE DEVICE INTO POSITION. CONTACT POWELL ELEC- TRICAL MANUFACTURING COMPANY FOR INSTRUCTIONS. C. X-RAYS When high voltage is applied across the contacts of a vacuum interrupter, there is the possible generation of x-rays. The intensity of this radiation is dependent on the peak voltage and the contact gap. At the normal operating voltage of this class of equipment, the radiation levels are negligible. At the voltages specified for testing, it is recommended that the test operator be no closer than one meter in front of the circuit breaker and separated from the vacuum interrupters under test by the two thickness of steel used in the construction of the circuit breaker frame. The circuit breaker must be either fully open or fully closed when making high potential test. Do not test with contacts partially open. POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 7

8 IB PowlVac Type PVDST Circuit Breaker D. SAFETY LABELS The circuit breaker has these warnings and caution labels attached at the indicated locations. Whenever the circuit breaker is handled or maintained, these warnings and caution labels must be observed. Label Type Description CAUTION Attached to the center face of circuit breaker blank panel. READ INSTRUCTIONS BEFORE ENERGIZING. THIS DEVICE MAY PRODUCE HARMFUL X-RAYS CAUTION Attached to the center face of circuit breaker blank panel. DO NOT PLACE BREAKER INTO CUBICLE WITHOUT INTERPHASE BARRIERS INSTALLED AND SECURELY FASTENED. Attached to the center face of circuit breaker blank panel. DANGER HAZARDOUS VOLTAGE WILL CAUSE SERIOUS INJURY OR DEATH. DE-ENERGIZE ALL POWER BEFORE REMOVING BARRIERS. REPLACE BARRIERS BEFORE ENERGIZING. DANGER BE SURE CIRCUIT BREAKER CONTACTS ARE OPEN AND SPRINGS DISCHARGED BEFORE PERFORMING ANY MAINTENANCE WORK. Attached to the center face of circuit breaker blank panel, and also in the mechanism compartment on dashpot bracket. DANGER Attached to the center face of circuit breaker blank panel. HIGH VOLTAGE KEEP OUT 8 POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA

9 PowlVac Type PVDST Circuit Breaker IB III. DESCRIPTION A. GENERAL The PowlVac Type PVDST Vacuum Circuit Breaker is a special version of the PowlVac Circuit Breaker, designed to replace a Federal Pacific Electric Company type DST. It is a modification of the PowlVac PV Vacuum Circuit Breaker, and replaces the DST air-magnetic circuit breaker. It is mounted on a frame similar to the frame of the type DST circuit breaker, and is equipped with primary disconnects, a secondary disconnect plug, interlocks, and wheels. The entire assembly will fit into a metal-clad switchgear cell designed for a PVDST circuit breaker without modification to that cell. All interlocking provided on type DST circuit breaker is also provided on the PowlVac Type PVDST vacuum circuit breaker. This PowlVac circuit breaker uses sealed vacuum interrupters (fig 1 [v]) to control the primary circuit. Primary connections to the associated metal-clad switchgear are made by parallel copper busbars terminating in fingers of the primary disconnects (fig 1 [l]). Insulating supports (fig 1 [t], [ab]) provide support for the primary disconnects and the vacuum interrupter assemblies. All the current carrying components are located behind a metal barrier which supports the insulators. In front of the barrier is the stored energy mechanism assembly, and it provides motion to each of the vacuum interrupter moving contacts through cast cycloaliphatic epoxy operating pushrods (fig 1 [z]). B. THE STORED ENERGY MECHANISM The front cover has cutouts and apertures giving access to various operating functions. Removal of ten (10) holding bolts enables the front cover to be removed giving access to the stored energy mechanism and its interlocks, auxiliary switches, levering-in interlocks, charging motor and operating solenoids. The mechanism is of the stored energy type in which a charging motor (fig 4 [t]) is used to compress a main closing spring (fig 4 [b]). During a closing operation, the energy stored in the main closing spring is used to close the vacuum interrupter contacts, compress the contact loading springs, charge the opening springs (fig 4 [a]) and overcome frictional forces. When the circuit breaker is tripped, the energy stored in the opening and contact loading springs will open the contacts at the correct speed. The motor, located on the circuit breaker floor pan bottom right, is supported by a bracket bolted to the floor pan. Its output shaft is screwed to a coupler, which inserts into the eccentric drive shaft. This shaft is supported in needle bearings in the mechanism frame side sheets and transmits the motor torque from the right to the left side of the mechanism. When the motor is energized, the eccentric shaft rotates and causes the driving arm links to pivot about the camshaft (fig 4 [y]). The drive pawl (fig 4 [l]) located on the links engages with the ratchet wheel (fig 4 [aa]) and rotates it, one tooth at a time. The ratchet wheel is prevented from rotating backward by a holding pawl support arms (fig 4 [h]), which is supported on links which projects upward from the camshaft. To insure correct synchronization of the drive and hold pawl, links are located by an adjustable eccentric stop (fig 4 [i]) located at the left front of the mechanism. When the mechanism is operated manually, the top pawl becomes the driving pawl and the bottom pawl becomes the holding pawl. POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 9

10 IB PowlVac Type PVDST Circuit Breaker As the ratchet wheel is rotated, projections from its side faces will engage drive plates attached to the camshaft and the camshaft will rotate. Attached to the ends of the camshaft are crank arms (fig 4 [n]), and pointing outward from these are crank pins (fig 4 [o]). These engage with the bottom ends of the connecting rods (fig 4 [c]), the top ends which engages with the pins, projecting from the spring compression plate, straddles the main closing spring. As the camshaft rotates, the connecting rods pull the spring compression plate downward, compressing the closing spring. The ratchet wheel will drive the camshaft so that the connecting rods go down to their lowest position and then start to move upward. At a certain point, the spring force will overcome friction and resistance and start to rotate the camshaft. At the same time, the pawls are uncoupled from the ratchet wheel by the pawl lift drive plate (fig 4 [ad]), and the motor cutoff switch is operated. The motor cutoff switch (fig 4 [u]) located on the right of the mechanism is operated by the spring charge flag falling onto the motor cutoff cam (fig 4 [v]). The spring charge flag will now show that the mechanism is charged. The camshaft would continue to rotate, except that it is restrained by the close latch arm (fig 4 [ac]) engaging against the close latch shaft (fig 4 [ab]). The main operating cam located between the mechanism side sheets is now in a position where the main drive linkage can move to the reset position (figure 2a). When the close latch is released, either under the action of the closing solenoid or the manual close plate, the closing spring pulls the camshaft around, and the main closing cam moves the main linkage into the closed position. The main linkage rotates the center lever to the drive jackshaft (fig 4 [p]). The jackshaft has 3 downward-pointing pairs of levers that are attached to operating pushrods. The operating pushrods (fig 1 [z]), which are approximately horizontal, are moved toward the vacuum interrupter (fig 1 [v]) by the rotation of the jackshaft. At the end of each operating pushrod is a recess, which encloses the contact loading spring (fig 1 [y]). At the end of this spring is the spring yoke (fig 1 [aa]), which connects with the bell crank (fig 1 [ac]). The spring yoke is restrained by a lock nut on a stud, which passes through the contact loading spring, and is attached to the operating rod. The contact loading spring has initial compression such that as soon as the vacuum interrupter contacts touch, they are loaded by a force sufficient to resist their separation under the highest electromagnetic forces exerted by the rated short circuit current. Further movement of the operating pushrods compresses the contact loading spring even more and produces a gap between the face of the spring yoke and the lock nut. This gap will reduce as the vacuum interrupter contacts erode. The bell cranks, which are located on the outside of lower primary disconnects are supported by operating pins (fig 1 [x]), that bridge the disconnects and are connected to drive pins, which passes through slots in the primary disconnects, bridging the bell cranks and engaging the extensions to the vacuum interrupters moving stems. The bell cranks give an approximate 3 to 1 multiplication of the contact loading spring force which permits reduced spring force and enables a low rate spring to be used. They also multiply the contact movement of approximately 0.5-inch by factor of 3 so that the mechanism linkages have relatively large movements and are less critical. In the linkage position shown in figures 2c and 2d, the contact loading springs and the main opening springs are both acting to compress the three (3) main mechanism links (fig 2). The linkage is restrained from movement by the secondary trip prop acting on the primary trip prop roller. The component of force tends to make the primary trip prop move upward, but it is restrained by the secondary trip prop face acting on the primary trip prop roller. The clearance between the primary trip prop roller and the secondary trip prop is controlled by the primary trip prop adjusting screw. When the trip shaft is rotated by the action of the manual trip plate or the electric trip solenoid, the secondary trip prop moves down and permits the primary trip prop to move upward, thus permitting the main linkage to move upward and the jackshaft to rotate, opening the circuit breaker. The jackshaft extends from the left to the right side of the circuit breaker frame and is supported at the main circuit breaker frame side sheets and by the mechanism side sheets. The two outer operating rod levers on the jackshaft have connections to the circuit breaker opening springs (fig 4 [a]). 10 POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA

11 PowlVac Type PVDST Circuit Breaker IB A projection of the left lever engages a shock absorber dashpot (fig 4 [f]), which controls the rebound of the interrupter contacts on opening operations. With the standard electrical control scheme, as soon as the closing springs are discharged on a closing operation, the motor is switched on to recharge the springs. This leaves the main closing cam in a position where the tripped linkage can reset under the action of the reset spring (fig 4 [z]), and the primary and secondary trip props can fall into the reset position. The reset spring stretches between an extension of the main cam roller pin and a spring support pin located on the left mechanism side sheet. The trip latch check switch (fig 4 [q]), operated by a lever on the trip shaft, will now close. C. ROLLOUT TRUCK The rollout truck of the PVDST circuit breaker is welded steel construction and is mounted on four wheels. This truck is equivalent to the truck of a type DST air-magnetic power circuit breaker and will fit in the cells designed for that circuit breaker. The truck is equipped with four steel wheels. These wheels are not made to swivel, so movement of the circuit breaker can be guided by steering the circuit breaker with the fifth wheel accessory, which is furnished with the original switchgear. D. SECONDARY CONTACTS The circuit breaker control wiring is arranged for a drawout disconnection by means of a 18 point male plug (fig 1 [p]). It is designed so that it connects to the corresponding cell mounted female receptacle. The secondary disconnect plug is mounted on a moveable bracket on the lower left rear side of the circuit breaker, which permits it to be extended to the rear while the circuit breaker is in the test position which makes contact with the stationary receptacle in the cell so that the control circuits are completed. Note that when the circuit breaker is withdrawn, the secondary disconnect automatically disengages. Normally, the secondary contacts are held stationary relative to the circuit breaker chassis. This is accomplished by a notch in the bar connecting the secondary contact hand operating rod to the secondary contact mounting bracket, which acts on the edge of the mechanism panel to hold the assembly in position. To engage the secondary contacts while the circuit breaker is in the test position, lift the secondary disconnect hand operating rod (fig 1 [f]) enough to release it from the mechanism panel and push to the rear until the secondary contacts engage. E. GROUND CONTACT The ground contact (fig 1 [r]) is an assembly of a busbar, which provides a disconnected means of grounding the circuit breaker chassis after it has been inserted into a switchgear cell. The ground connection is located on the underside of the chassis next to the left-hand rear wheel of the circuit breaker. An extension of the switchgear s ground bus is secured on the cell s rear wall, which engages with the ground contact when the circuit breaker is in the fully connected position. F. LEVERING-IN DEVICE Caution: Operating the levering-in mechanism will trip the circuit breaker if it is closed. The levering-in device is the mechanical assembly that moves the circuit breaker between the test position and the connected position in the cell. The device has a levering-in shaft that is supported by the frame, and it has a worm gear at one end, and a hex racking shaft at the other end. The cam rollers that are attached to the shaft will engage the horizontal slots in the cell structure, and rotation of the cam rollers will allow the interlock assembly to engage, and the circuit breaker will move in and out of the cell. POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 11

12 IB PowlVac Type PVDST Circuit Breaker o a b g aj c d e i k j h l q p f s r t ah m n af ae u v f ag ad ac w x y ai a. Blank Panel b. Handle c. Nameplate d. Manual Charging Crank e. Operations Counter f. Secondary Disconnect Hand Operating Rod g. Cover Attachment Bolts h. Spring Charge Indicator i. Manual Trip Paddle j. Breaker Open/Closed Indicator k. Manual Close Paddle l. Primary Disconnect m. Shutter Lift n. Wheel o. Levering-in Device p. Secondary Disconnect Plug q. Cell Interlocks r. Ground Contact s. Adapter Bus t. Main Insulating Support (Wishbone) u. Strut kit v. Vacuum Interrupter w. Sliding Contact Finger Assembly x. Operating Pin y. Contact Loading Spring ab aa z. Operating Pushrod aa. Spring Yoke ab. Insulating Pole Support ac. Bell Crank Lever ad. Horizontal Connector Bar ae. Bus Boot af. Vertical Connector Bar ag. Lift-to-Trip Lever ah. Racking Shaft ai. Turning Dolly aj. Lift Point z See section on Recommended Renewal Parts and Repair Procedures for part number identification and replacement procedures. Figure 1. Exterior Components 12 POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA

13 PowlVac Type PVDST Circuit Breaker IB a 2b 2c 2d Figure 2. Cam and Fundamental Linkage Positions a. Secondary Trip Latch Adjusting Screw b. Trip Bar c. Secondary Trip Prop d. Secondary Linkage Roller e. Main Cam Roller f. Reset Spring g. Camshaft h. Main Drive Cam j. Center Phase Operating Lever k. Main Jackshaft l. Primary Trip Prop Roller m. Primary Trip Latch Adjusting Screw n. Primary Trip Prop Figure 3. Mechanism and Trip Linkages POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 13

14 IB PowlVac Type PVDST Circuit Breaker a a b f c e d i p q c p o n ad m l g h v y ae j u k r t s ad ac l m aa ab k z w x Figure 4. Interior Components j y 14 POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA

15 PowlVac Type PVDST Circuit Breaker IB a. Opening Spring b. Main Closing Spring c. Connecting Rod d. Auxiliary Switch e. Primary Shunt Trip Coil f. Shock Absorber (Dashpot) g. Secondary Trip Latch Adjusting Screw h. Holding Pawl (Support Arm) i. Holding Pawl Adjusting Eccentric j. Main Operating Cam k. Closing Coil l. Drive Pawl m. Pawl Support Arm n. Crank Arm o. Crank Pin p. Jackshaft q. Latch Check Switch r. Breaker Closing Release Interlock Arm s. Motor Limit Switch t. Charging Motor u. Motor Cutoff Switch v. Motor Cutoff Cam w. Secondary Trip Prop x. Main Cam Roller y. Camshaft z. Mechanism Reset Spring aa. Rachet Wheel ab. Close Latch Shaft ac. Close Latch Arm ad. Pawl Lift Plate ae. Close Bar Adjusting Screw See section on Recommended Renewal Parts and Repair Procedures for part number identification and replacement procedures. The interlock is activated by a levering-in shaft that supports a worm at the center rear of the circuit breaker frame. The worm gear is rotated by the worm on a worm shaft, which then rotates the upper an lower cam rollers. As the lower cam roller (fig 5 [b]) rotates, the bolt (fig 5 [g]) assembled to the cam on the cam roller rotates, depressing the interlock link arms (fig 5 [d]). When the interlock link arms are depressed, f the interlock assembly rotates forward, allowing the circuit breaker to discharge and g move between the test position and the connected position. d The main components of the levering-in device and cell interlocks are shown in figures 5. Figure 4 Interior Components a b G. SHUTTER LIFT The shutter lift (fig 1 [m]) is located on the right side of the circuit breaker chassis. The shutter lift function is to engage the shutter operating lever in the cell to raise the shutter over the stationary primary disconnects as the circuit breaker is levered into the cell. e d a. Upper roller cam b. Lower roller cam c. Trip shaft d. Interlock link arm e. Trip interlock shaft f. Trip interlock shaft adjusting nuts g. Bolt c Figure 5. Levering-in Device and Cell Interlocks POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 15

16 IB PowlVac Type PVDST Circuit Breaker H. INTERLOCKING The PowlVac PVDST circuit breaker is provided with several interlocks, which operate in conjunction with the switchgear cell to insure the proper operation of the circuit breaker. These interlocks function in the same manner as the interlocks provided on the Type DST circuit breaker which the PVDST circuit breaker replaces. Do not attempt to modify or bypass these interlocks, as they are necessary for the safe operation of the circuit breaker. The interlocks provided are: 1. Levering-in Interlock a b c The levering-in interlock is designed to prevent moving the circuit breaker in or out of the connected position if the circuit breaker contacts are closed. The levering in interlock consist of an interlock bar (fig 6 [d]) that prevents the insertion of the racking handle, unless the interlock bar is raised. When the circuit breaker is in the test position, and the interlock bar is raised by lifting the lift-to-trip lever (fig 6 [c]), the racking handle can then be inserted onto the hex racking shaft (fig 6 [a]). This action will trip the circuit breaker, thus allowing movement of the circuit breaker from the test position to the connected position. d a. Racking Shaft b. Trip Shaft Arm Lift Assembly c. Lift-to-Trip Lever d. Interlock Bar Lifting the lift-to-trip lever will allow for the racking Figure 6. Levering-in Interlock handle to be inserted onto the hex racking shaft. When the circuit breaker is in the connected position, and the interlock bar is raised by lifting the lift-to-trip lever, the circuit breaker is then released from the bottom of the cell. The circuit breaker can then be moved from the fully connected position to the test position. 16 POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA

17 PowlVac Type PVDST Circuit Breaker IB Cell Interlocks The cell interlocks operate to trip the circuit breaker and discharge the main closing spring when the circuit breaker is inserted into the cell to the test position or removed from the cell. The cam plates on the cell floor will lift the trip/close assembly levers on the underside of the circuit breaker which trips the circuit breaker and/or discharge the main closing spring. The circuit breaker is held trip free by a shaft that has a cam which keeps the trip linkage from returning to its normal position, holding the circuit breaker in the tripped position until it reaches either the fully connected position or test position. The cell interlock levers on the underside of the circuit breaker are coupled to a trip/close link assemblies located in the mechanism housing of the circuit breaker which operate to engage the circuit breaker tripping and closing mechanisms. See figures 5 and 6. I. OPERATING SOLENOIDS The closing coil (fig 4 [k]) is an operating solenoid that is located center and beneath the mechanism, and attached to the circuit breaker floor pan by two screws, which are accessible from underneath the circuit breaker. The primary shunt trip coil (fig 4 [e]) is to the left of the mechanism and is supported from the lower frame channel. Either a secondary shunt trip coil or an undervoltage trip device may be furnished as an option. When furnished, either of these devices can be located to the right of the mechanism and is supported from the lower frame channel. Only one of these two auxiliary trip devices may be furnished on any one circuit breaker, as both types are located in the same space. J. MOTOR CUTOFF SWITCH The motor cutoff switch (fig 4 [u]), located at the right side of the mechanism, is attached to a bracket, which is bolted to the circuit breaker floor pan. K. VACUUM INTERRUPTERS For a listing of the vacuum interrupters used in PowlVac PVDST circuit breakers, see Table II. Each vacuum interrupter bears a label that indicates its part number. Vacuum interrupters must be replaced only with new interrupters of the same part number. Refer to the circuit breaker supplemental instructions for the applicable vacuum interrupter description and maintenance procedures. L. CONTROL CIRCUIT A Typical DC control scheme is shown in figure 7. The control scheme of any particular circuit breaker may differ from this scheme, depending on the user s requirements and the auxiliary devices furnished with that circuit breaker. Check the wiring diagram supplied with the actual circuit breaker for its wiring. The sequence of the operation for all control schemes is shown in figure 8. POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 17

18 IB PowlVac Type PVDST Circuit Breaker M. ANTI-PUMP RELAY Type PVDST circuit breakers do not include an anti-pump relay, as the existing 52X-Y relay in the switchgear cell performs this function. When required, the anti-pump will be located on the circuit breaker s left upper frame, right of the opening spring. Figure 7. Typical DC Control Scheme 18 POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA

19 PowlVac Type PVDST Circuit Breaker IB Figure 8. Operation Sequence POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 19

20 IB PowlVac Type PVDST Circuit Breaker IV. INSTALLATION A. RECEIVING When the circuit breaker is received, check for signs of damage. If damage is found or suspected, file claims as soon as possible with the transportation company, and notify the nearest representative at Powell Electrical Manufacturing Company. B. HANDLING The circuit breaker is equipped with four large wheels so that it may be rolled easily on level floors. A turning dolly may be used to facilitate handling. When used with outdoor switchgear, the circuit breaker may be handled using the transfer truck supplied with the original switchgear. The circuit breaker must not be lifted from beneath the frame with a forklift or similar device, as components beneath the circuit breaker could be damaged. C. STORAGE It is recommended that the circuit breaker be placed into service immediately in its permanent location. If this is not possible, the following precautions must be taken to assure the proper storage of the circuit breaker: 1. The circuit breaker should be carefully protected against condensation, preferably by storing it in a warm dry room of moderate temperature, such as F, since dampness has an adverse effect on the insulating parts. Circuit breakers for outdoor metal-clad switchgear should be stored in the equipment only when power is available and the heaters are in operation to prevent condensation. 2. The circuit breaker should be stored in a clean location free from corrosive gases or fumes. Particular care should be taken to protect the equipment from moisture and cement dust, as this combination has a very corrosive effect on many parts. If the circuit breaker is stored for any length of time, it should be inspected periodically to see that rusting has not started and to insure good mechanical condition. Should the circuit breaker be stored under unfavorable atmospheric conditions, it should be cleaned and dried out before being placed in service. 20 POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA

21 PowlVac Type PVDST Circuit Breaker IB CAUTION HIGH VOLTAGES ACROSS THE OPEN GAPS OF THE VACUUM INTERRUPTER CAN PRODUCE RADIATION. PERSON- NEL SHOULD STAND AT LEAST ONE METER AWAY FROM THE CIRCUIT BREAKER, WITH THE COVERS IN PLACE, WHEN CONDUCTING HIGH VOLTAGE TEST. TEST VOLTAGE SHOULD NOT EXCEED 36kVAC, 50 OR 60Hz, OR 50kVDC. CAUTION WHEN TESTING WITH DC, USE A DC HIGH POTENTIAL TEST (Hipot) SET WITH FULL WAVE RECTIFICATION. MANY DC HIGH POTENTIAL TEST SETS USE HALF- WAVE RECTIFICATION. DO NOT USE THESE HALF-WAVE RECTIFIERS. THE CAPACITANCE OF THE VACUUM INTER- RUPTER IN COMBINATION WITH THE LEAKAGE CURRENTS IN THE RECTIFI- ERS AND ITS DC VOLTAGE MEASURING EQUIPMENT MAY RESULT IN APPLYING PEAK VOLTAGES AS MUCH AS THREE TIMES THE MEASURED VOLTAGE. THESE ABNORMALLY HIGH VOLTAGES MAY GIVE A FALSE INDICATION OF A DEFECTIVE INTERRUPTER, AND MAY PRODUCE ABNORMAL X-RADIATION. CAUTION APPLYING ABNORMALLY HIGH VOLTAGE ACROSS A PAIR OF CONTACTS IN VACUUM MAY PRODUCE X-RADIATION. THE RADIATION MAY INCREASE WITH THE INCREASED VOLTAGE AND/OR DECREASE IN CONTACT SPACING. X-RADIATION PRODUCED DURING THIS TEST WITH THE RECOMMENDED VOLT- AGE AND NORMAL CONTACT SPACING IS EXTREMELY LOW AND WELL BELOW MAXIMUM PERMITTED BY STANDARDS. HOWEVER, AS A PRECAUTIONARY MEASURE AGAINST POSSIBILITY OF APPLICATION OF HIGHER THAN RECOMMENDED VOLTAGE AND/OR BELOW CONTACT SPACING, IT IS RECOMMENDED THAT ALL OPERATING PERSONNEL STAND AT LEAST ONE METER AWAY IN FRONT ON THE CIRCUIT BREAKER. DO NOT APPLY VOLTAGE THAT IS HIGHER THAN THE RECOMMENDED VALUE. DO NOT USE CONTACT SEPARA- TION THAT IS LESS THAN THE NORMAL OPEN POSITION SEPARATION OF THE BREAKER CONTACTS. CAUTION CAUTION Remove all grounding conductors applied for this test before placing the circuit breaker back into service. If DC high potential testing (Hipot) is required, the DC high potential test machine must not produce instantaneous peak voltages exceeding 50kV. POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 21

22 IB PowlVac Type PVDST Circuit Breaker D. PUTTING INTO SERVICE Before shipment from our factory, all circuit breaker functions will have been thoroughly checked. The user must recheck the operation, Powell Electrical manufacturing company recommends that the check be performed in sequence listed below: 1. Commissioning 2. High voltage insulation integrity 3. Vacuum integrity 4. Control voltage insulation integrity 5. Mechanical operation check 6. Electrical operation check 7. Dimensional check 1. Commissioning Refer to the original equipment s instruction book, and use the Annex section in this instruction bulletin as a general guide. 2. High Voltage Insulation Integrity The circuit breaker s high voltage insulation system, which consists of the pushrods and conductor supports assemblies, should be hipot tested prior to initially putting the circuit breaker in service or following the interruption of a fault. The circuit breaker primary phase-to-phase and phase-to-ground insulation should be tested with the circuit breaker in the closed position. Test each pole of the circuit breaker separately, with the other two poles and the circuit breaker frame grounded. Field maintenance insulation resistance testing can be conducted with either AC or DC high potential testing (Hipot). DC testing is very common due to the availability of the equipment. Consistent and historical readings are more important than predetermined values. A clean dry circuit breaker will help yield accurate and consistent readings. Recommended maintenance test voltages for PowlVac circuit breakers are: 15kV circuit 27kVAC or 37kVDC for one minute. 3. Vacuum Integrity Powell recommends AC testing for reliable verification of vacuum integrity. Presently, all PowlVac 5kV and 15kV circuit breakers should be tested with a minimum of 25kVAC applied across fully open contacts for 10 to 15 seconds. No dielectric breakdown during the test period constitutes a successful test. Note, this test does not replace the AC high potential testing (Hipot) used to determine high voltage insulation integrity. See the high voltage insulation integrity section. Powell offers a compact and lightweight AC vacuum interrupter integrity test set, designed specifically for PowlVac circuit breakers, which provides the appropriate 25kVAC voltage for the prescribed time. This test set eliminates the element of leakage interpretation. Two high voltage leads are connected across a fully open vacuum interrupter and the test is initiated. A red neon lamp indicates the test is in progress. The test is automatically timed and terminated with a green LED for pass, or a red LED for fail. Contact Powell Apparatus Service Division (PASD) for more information. 22 POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA

23 PowlVac Type PVDST Circuit Breaker IB Powell recognizes the widespread use of DC hipot equipment in the field and the desire to use this equipment to verify vacuum integrity. However, the capacitive component of the vacuum interrupter during DC testing may yield false negative test results, which are often misinterpreted as vacuum interrupter failure. Several testing companies and customers insist on the use of DC testing. When DC testing is preferred, a test set providing a full wave rectified 50kV DC hipot voltage can be applied for 5 seconds as a go - no go test. Recording the leakage readings is not necessary, as a dielectric breakdown will trip all portable DC hipot test sets. If a DC test breakdown occurs, the test must be repeated after reversing the DC polarity across the vacuum interrupter. A vacuum interrupter should be questioned only if it has failed both DC polarity tests. 4. Control Voltage Insulation Integrity If the user wishes to check the insulation integrity of the control circuit, it may be done with a 500-volt or 1000 volt insulation tester or with an AC hipot tester. The AC hipot test should be made at 1125 volts, 60Hz, for one minute. The charging motor must be disconnected at its connection plug prior to testing the control circuit. The motor itself may be similarly tested at a voltage not to exceed 675 volts, 60Hz. Be sure to remove any test jumpers and reconnect the charging motor when the tests are complete. 5. Mechanical Operation Check To check the mechanical operation of the circuit breaker, insert the manual charging handle into the manual charging crank (fig 1 [d]) and push down until a metallic click is heard. This indicates that the holding pawl has dropped into place on the ratchet wheel. Lift the handle until it is horizontal and then depress. The procedure is repeated until the spring charge flag indicates that the main close spring is now charged. This requires about 60 operations of the handle. Remove the handle. Push the round blue push to close plate (fig 1 [k]) and the circuit breaker will close. The flag located above the push to close plate will now read closed. Push the round red trip plate (fig 1 [i]) located at the top of the escutcheon and the circuit breaker will open as indicated by the circuit breaker condition flag. 6. Electrical Operation Check To check the electrical operation of the circuit breaker, the circuit breaker must be moved to the test position. A test box or test plug may be used to verify the electrical operation check. See the section, Inserting the Circuit Breaker into the Switchgear Equipment. 7. Dimensional Check When inserting the circuit breaker into the switchgear equipment, it may be necessary to shim the circuit breaker wheels to ensure proper alignment. When the circuit breaker has been inserted and fully levered into the cell, there may be a gap or binding between the circuit breaker front cover, and the cell gas barrier. Shims may be used on the front cover to give a correct fit and finish between the front cover and the cell gas barrier. POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 23

24 IB PowlVac Type PVDST Circuit Breaker E. INSERTING CIRCUIT BREAKER INTO SWITCHGEAR EQUIPMENT Refer to the instruction bulletin provided with the original switchgear equipment for instructions covering insertion of the circuit breaker into the switchgear equipment. 1. Examine the Primary Disconnecting Fingers Examine the primary disconnecting fingers for any signs of damage. See that they are properly positioned and that the retaining bolts are in place in the end of the circuit breaker studs. Clean off any dirt, paper, etc.. Check the secondary contacts to see that none are bent out of alignment. Make sure that the cell is clean and clear of anything that might interfere with circuit breaker travel. NOTE: THE CIRCUIT BREAKER MUST BE TRIPPED OPENED BY LIFTING THE LIFT TO TRIP LEVER BEFORE MOVING THE CIRCUIT BREAKER BETWEEN THE TEST AND CONNECTED POSITION. 2. Lever the Circuit Breaker into the Test Position in the Cell Lift the lift to trip lever, and insert the racking handle and rotate counterclockwise until the levering-in assembly is against its stop, and then remove the racking handle. This assembly is in the rear of the circuit breaker, and the racking-in lever should protrude outside the frame before putting the circuit breaker in the cell. Line up the circuit breaker s two rear wheels with the guide rails on the bottom left and right hand side of the floor cell. Push the circuit breaker towards the rear wall of the cell until the levering-in assembly makes contact with the horizontal racking-in hook of the cell. Then lift the lift to trip lever, insert the racking handle, and rotate clockwise. The circuit breaker will initially back out of the cell, and then move forward to the test position as seen by the indicator on the right-hand side of the cell. Remove the racking handle. KEEP HANDS OFF TOP EDGE OF FRONT STEEL BARRIER WHEN PUSHING CIRCUIT BREAKER INTO CELL. The circuit breaker is now in TEST POSITION. 3. Engage the Secondary Contacts Lift the handle on the left-hand side of the chassis front to a horizontal position. Lift further to disengage the notch in the rod from the top edge of panel and push towards the rear of the circuit breaker. The small horizontal pin in the handle will engage the two slots in the lever, which is pivoted immediately above the handle. Push down on the curved end of the lever as far as it will go. NOTE: AS SOON AS THE SECONDARY CONTACTS CONNECT, THE CHARGING MOTOR WILL CHARGE THE CLOSING SPRING IF THE CONTROL CIRCUIT IS ENERGIZED. 24 POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA

25 PowlVac Type PVDST Circuit Breaker IB Operate the Circuit Breaker as Required The circuit breaker may now be electrically closed and tripped several times to assure that all control circuit connections and contacts are satisfactory. This should be done on a dead bus if possible, if operating on a live bus, close and fasten the cell door and practice the safety precaution before preforming this operation. The control of the circuit breaker is arranged so that the closing spring will recharge immediately after each closing operation. 5. Trip the Circuit Breaker Open Trip the circuit breaker open by manually pushing the push to trip, control switch on the cell, or by lifting the lift to trip lever of the circuit breaker. 6. Lever the Circuit Breaker into the Connected Position A mechanical interlock prevents levering circuit breaker into or out of the cell if circuit breaker is closed. Lift the lift to trip lever, insert the racking handle on the racking shaft and turn clockwise. The shutters in the cell will open, allowing the contacts, and primary disconnects to make contact. The secondary disconnect will automatically push forward and lock in place as the circuit breaker reaches the connected position. The indicator on the cell s right-hand wall will read the connected position. Remove the racking handle. 7. Operate the Circuit Breaker as Required Operate the circuit breaker as required, the racking handle must be removed. The circuit breaker may now be electrically closed and tripped several times to assure that all control circuit connections and contacts are satisfactory. This should be done on a dead bus if possible, if operating on a live bus, close and fasten the cell door and practice the safety precaution before preforming this operation. The control of the circuit breaker is arranged so that the closing spring will recharge immediately after each closing operation. 8. Trip the Circuit Breaker Open Trip the circuit breaker open by manually pushing the push to trip, control switch on the cell, or by lifting the lift to trip lever of the circuit breaker. Caution The pole unit parts are alive at full circuit voltage when the circuit breaker is in the fully engaged position. Before moving the circuit breaker into that position, make sure the main barrier assembly has been properly fastened in place. Failure to do this may cause serious damage or injury. 9. Remove the Circuit Breaker from the Connected Position Lift the lift to trip lever to trip the circuit breaker open. Insert the racking handle onto the racking shaft and turn counterclockwise until the racking handle rotates to a stop, and then remove the racking handle. The circuit breaker is then secured in the Test position, and the cell s indicator will read Test position. 10. Remove the Circuit Breaker from the Cell Pull the circuit breaker completely out of cell using the handles on the front cover. NOTE: BEFORE INSERTING THE RACKING HANDLE, THE CIRCUIT BREAKER MUST BE TRIPPED. POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 25

26 IB PowlVac Type PVDST Circuit Breaker V. MAINTENANCE Contact Powell Apparatus Service Division for assistance in performing maintenance or setting up a maintenance program. The website is located at or call A. GENERAL 1. Introduction A regular maintenance schedule should be established to obtain the best service and reliability from the circuit breaker. PowlVac circuit breakers are designed to comply with industry standards requiring maintenance every 2000 operations or once in the first year, and then the interval can be extended depending on the environment. Actual inspection and maintenance will depend upon individual application conditions such as number of operations, magnitude of currents switched, desired overall system reliability, and operating environment. Any time the circuit breaker is known to have interrupted a fault current at or near its rating, it is recommended that the circuit breaker be inspected and necessary maintenance be performed as soon as practical. Some atmospheric conditions such as extremes of dust, moisture, or corrosive gases might indicate inspection and maintenance at more frequent intervals than 2000 operations. Very clean and dry conditions combined with low switching duty will justify longer times between inspection and maintenance operations. With experience, each user can set an inspection and maintenance schedule that is best suited for the particular use. A permanent record of all maintenance work should be kept, the degree of detail depends on the operating conditions. In any event, it will be a valuable reference for subsequent maintenance work and for station operation. It is recommended that the record include reports of tests made, the condition of circuit breakers, repairs, and adjustments that were made. This record should begin with any checks done at the time of installation. Because of extensive quality control checks made at the factory, the operations counter on a new circuit breaker will normally register over a hundred operations. The actual reading of the operations counter should be recorded when the circuit breaker is put into service and whenever any maintenance is performed. Before attempting any maintenance work, take note of safety practices outlines in Section II of this bulletin. CAUTION MAKE CERTAIN THAT THE CONTROL CIRCUITS ARE DE-ENERGIZED AND THE CIRCUIT BREAKER IS RESTING SECURELY OUTSIDE THE SWITCHGEAR HOUSING. DO NOT WORK ON A CLOSED CIRCUIT BREAKER OR A CIRCUIT BREAKER WITH THE CLOSING SPRING CHARGED. 26 POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA

27 PowlVac Type PVDST Circuit Breaker IB Inspection and Cleaning Give the circuit breaker a visual check for loose or damaged parts. Tighten or replace loose or missing hardware. Any part damaged to interfere with normal operation of the circuit breaker should be replaced. This inspection will be much easier if the front cover and interphase barrier assembly is removed. Clean the circuit breaker, removing loose dust, and dirt. Do not use an air hose to blow the circuit breaker out; this may result in loose dirt or grit being blown into bearings or other critical parts and causing excessive wear. Either use a vacuum cleaner or wipe with a dry lint-free cloth or an industrial-type wiper. Primary insulation, including the interrupter supports and the operating pushrods, should be cleaned also. Wipe clean with a dry lint-free cloth or an industrial type wiper. If dirt adheres and will not come off by wiping, remove it with distilled water or a mild solvent such as denatured alcohol. Be sure that the circuit breaker is dry before returning it to service. Do not use any type of detergent to wash the surface of the insulators, as detergent may leave an electrical conducting residue on the surface as it dries. Caution When cleaning the circuit breaker support insulators and bus insulation, use only denatured alcohol or isopropyl alcohol to remove foreign material. Failure to do so may damage the dielectric and/or the mechanical properties of the insulation. B. MECHANISM AREA 1. Mechanical Operation Remove the circuit breaker front cover, exposing the mechanism. Make a careful visual inspection of the mechanism for loose or excessively worn parts. Operate the circuit breaker several times manually. See the section headed Mechanical Operation Check under the heading Putting into Service for further information. 2. Lubrication Lubricate the mechanism and other specified parts in accordance with the lubrication chart, Table I. Powell offers a complete lubrication kit (Powlube-102) which contains all the lubricants required for maintaining 6-10 circuit breakers. The chart shows the location of all surfaces that should be lubricated together with the type of lubricant and method of application. The guiding rule in lubrication should be to lubricate regularly, use lubricant sparingly, and remove all excess lubricant. Rheolube-368A is interchangeable with Anderol 757 Grease and should be lightly applied to those bearing surfaces that are accessible. A light synthetic machine oil such as Anderol 456 should be used to penetrate the surfaces, which are inaccessible. Mobilgrease 28 should be applied to the contact surfaces. Before applying any type of lubrication to the circuit breaker, the mechanism should not be charged, and all springs should be discharged. There is no necessity to disassemble the mechanism for lubrication. Tilting the circuit breaker will facilitate the entry of the lubricant to the bearing surfaces. POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 27

28 IB PowlVac Type PVDST Circuit Breaker 3. Closing Spring Removal and Slow Closing of Mechanism Disassembly of the mechanism is not required for routine lubrication. However, for major overhaul, removal of the closing spring is necessary. Removal of the spring permits slow closing of the vacuum interrupter contacts. The procedure for spring removal is as follows: With closing spring discharged and circuit breaker contacts open, remove the screw at the top of the spring rod together with the flat washer and lock washer. Remove the right-angle bracket by unfastening the two attachment screws. Remove the spacer from below the bracket. Turn the bracket 90 and replace it on top of the spring yoke. Place the spacer on top of the bracket with the flat washer above it. Insert screw and screw down until tension is taken off the connecting rods (figure 9). The connecting rods are of a keyhole design and can now be unhooked from the spring yoke pins and the spring assembly removed with a slight rocking motion. Care should be taken during reassembly to insure correct location of the flat washer, lock washer, and spacer. See figure 10. With the main spring assembly removed, rotate the camshaft so that the crank arms are pointing downward. The main linkage will now move into the reset position. Push the manual close paddle and hold in while operating the hand charge lever to rotate the camshaft. Once the close release latch arm is past the close shaft latch plate, the manual close paddle may be released. As the main cam engages the main linkage roller, the jackshaft will commence to rotate. Continue to operate the hand charge lever until the crank arms point upward. The circuit breaker will now be closed and there will be a gap between the contact overtravel nuts and the contact spring yokes. c Figure 9. Main Closing Spring Assembly Compressed for Removal a. Connecting Rod b. Flat Washer c. Screw b a d Figure 10. Main Closing Spring Assembly Installed a. Bracket b. Spacer c. Flat Washer d. Screw e. Lock Washer e a c b 28 POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA

29 PowlVac Type PVDST Circuit Breaker IB Mechanism Adjustments Several factory adjustments in the mechanism are described below. No adjustment of these settings is required for routine maintenance, but they may need to be adjusted after major overhaul or removal of the mechanism. DO NOT ADJUST THESE SETTINGS UNNECESSARILY, AS MECHANICAL DAMAGE MAY OCCUR. a. Adjustment of Ratchet Wheel Holding Pawl The ratchet wheel holding pawl support arm (fig 4 [h]) is adjusted by an adjusting eccentric cam (fig 4 [i]). If the pawl is not properly adjusted, there will be a knocking noise when the ratcheting mechanism is operating, or the mechanism will not ratchet at all. To adjust the pawl, remove the escutcheon to gain access to the head of the bolt holding the eccentric cam. Loosen the bolt slightly. While charging the spring using the charging motor to drive the mechanism, grip the eccentric cam with a pair of slip-joint pliers or a similar tool and rotate the cam slightly until the ratcheting operation is smooth. This may require several charging cycles, as each charging cycle lasts only a few seconds. When the eccentric cam is properly set, retighten the mounting bolt and replace the escutcheon. Be sure that the escutcheon is reinstalled on the proper circuit breaker, since the escutcheon contains the nameplate with all the circuit breaker s rating and serial number information. b. Adjustment of Primary and Secondary Trip Latches and Latch Check Switch Adjust the secondary trip latch adjusting screw (fig 4 [g]) so that the overlap of the secondary trip prop on the primary trip prop roller is approximately inch. Adjust the primary trip latch adjusting screw (fig 11) so that with the main linkage in the reset position the clearance between the primary trip latch roller and the secondary trip prop is inch. The primary trip latch adjusting screw is accessible from the rear of the mechanism, between the legs of the lower center phase support insulator. With a inch wire gauge between the trip bar lever and the secondary trip latch adjusting screw, the latch check switch should be open. With no gap between the lever and the screw, the latch check switch should be closed. Figure 11. Primary Trip Latch Adjusting Screw c. Adjustment of Close Latch The close shaft passes through the side sheets of the mechanism frame at the front of and below the camshaft. The left end of the shaft is shaped to make a latch face and interferes with the latch arm (fig 4 [ac]), which is fixed to the camshaft. The other end of the close shaft is on the right side of the mechanism and a small lever attached to it is positioned by an adjusting screw. With the main closing spring charged, turn the latch adjusting screw inward toward the rear of the circuit breaker until the latch is released and the circuit breaker closes. Unscrew the adjustment screw 2 1/2 turns and lock in position with the locking nut. 5. Electrical Operation After any necessary mechanical maintenance and lubrication are done, operate the circuit breaker electrically several times to ensure that the electrical control system works properly. See section headed Electrical Operation under the Putting into Service heading in this instruction bulletin. POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 29

30 IB PowlVac Type PVDST Circuit Breaker Table l. Lubrication L oca oitn R.fe Figure ulbricant Method E el Placirtc arts P rimary Disconnect Fig 1 [l] Mobilgrease 28 G round Contact Fig 1 [r] Mobilgrease 28 S liding Contact Blocks F ig 12 [ N] Mobilgrease 28 Secondary Disconnect Plug Mechanical Parts Fig 1 [p] Mobilgrease 28 Wipe clean. surface. Wipe clean. surface. Apply lubricant only to actual contact Apply lubricant only to actual contact With circuit breaker closed, wipe clean and apply thin smear of lubricant a bove sliding contact fingers. Wipe clean. surface. Apply lubricant only to actual contact C amshaft Needle Bearings F ig 12 [ T] C rank Pins F ig 12 [ G] S pring Yoke Pin F ig 12 [ A] R atchet Wheel F ig 12 [ K] P awls F ig 12 [ J] P awl Support Arms F ig 12 [ H] M ain Spring Guide Rod F ig 12 [ B] Motor Drive Shaft Support F ig 12 [ V] Bearings Motor Drive Shaft Roller F ig 12 [ M] Needle Bearings Motor Drive Shaft F ig 12 [ X] Coupling F lag Support Pin F ig 12 [ U] Close Shaft Support F ig 12 [ R] Bearing Close Latch Shaft F ace Fig 12 [L] P rimary Trip Prop F ig 12 [ Q] M ain Linkage F ig 12 [ S] F ixed Linkage Pin F ig 12 [ I] Trip Shaft Support F ig 12 [ F] Bearings Jackshaft Outer Bearings F ig 12 [ C] Support Jackshaft Supports at F ig 12 [ D] Mechanism Flag Drive Lever at F ig 12 [ Y] Jackshaft M otor Cutoff Cam F ig 12 [ W] Jackshaft Lever Pins F ig 12 [ E] Passing Through Pushrods Cell Interlock Trip Inner F ig 12 [ P] Shaft C ell Interlock Linkage F ig 12 [ O] Anderol 456 Oil Anderol 456 Oil Anderol 456 Oil Rheolube 368A Grease Anderol 456 Oil Anderol 456 Oil Anderol 456 Oil Anderol 456 Oil Anderol 456 Oil Anderol 456 Oil Anderol 456 Oil Anderol 456 Oil R heolube 368A Grease Apply a light coating of grease and remove all excess. Anderol 456 Oil A nderol 456 Oil Apply to penetrate where pins pass through lines. A nderol 456 Oil Apply to penetrate where pin passes through end link. Anderol 456 Oil Anderol 456 Oil Anderol 456 Oil Anderol 456 Oil R heolube 368A Grease Apply to peripheral surface only. A nderol 456 Oil Avoid lubricant on pushrods. Anderol 456 Oil Anderol 456 Oil Note: 1. Powlube-102 is a PowlVac lubrication kit that consist of: a. One 2-oz Anderol 456 needle applicator oil b. One 2-oz Rheolube 368A grease tube c. One Mobilgrease 28 tube 2. Rheolube 368A grease is interchangeable with Anderol 757 grease. 30 POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA

31 PowlVac Type PVDST Circuit Breaker IB A B A. Spring Yoke Pin B. Main Spring Guide Rod F D C E I H K L M M C. Jackshaft D. Jackshaft Outer Bearing Support G J E. Jackshaft Lever Pin F. Trip Shaft Support Bearing G. Crank Pin H. Pawl Support Arms I. Fixed Linkage Pin J. Pawl K. Rachet Wheel L. Close Latch Shaft Face M. Motor Drive Shaft Roller Needle Bearing Figure 12. Lubrication POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 31

32 IB PowlVac Type PVDST Circuit Breaker O P S T R N Q U Y W V N. Sliding Contact Block X O. Cell Interlock Linkage P. Cell Interlock Trip Inner Shaft Q. Primary Trip Prop R. Close Shaft Support Bearing S. Main Linkage T. Camshaft Needle Bearings U. Flag Support Pin V. Motor Drive Shaft Support Bearing W. Motor Cutoff X. Motor Drive Cam Shaft Coupling Y. Flag Drive Lever at Jackshaft Figure 12. Lubrication 32 POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA

33 PowlVac Type PVDST Circuit Breaker IB C. VACUUM INTERRUPTER AND CONTACT AREA 1. Vacuum Interrupter Contact Erosion At each inspection, the vacuum interrupters should be checked for contact erosion. The circuit breaker must be closed for this check. Each new vacuum interrupter is set with an overtravel gap about 7/16 to 5/8 inch between the contact loading spring yoke and the nut on the pushrod stud. As the contacts erode with use, this gap will decrease. Because the factory setting of the overtravel gap varies slightly for each interrupter, a label is provided on the lower part of each interrupter. The original factory setting of the overtravel gap and the end-of-life measurement of this gap are recorded on this label. When the overtravel gap measurement reaches the end-oflife value given on this label, the interrupter should be replace. Detailed instructions for this replacement are given in the supplementary instructions, which accompany this instruction bulletin, for each type of vacuum interrupter. 2. Sliding Contact Finger Wear Remove the four socket-head screws holding the sliding contact assemblies and pivot the assemblies down. Wipe the lubricant from the surfaces of the lower contact block, the fingers and the lower main horizontal primary disconnects and examine these surfaces. The finger locations should present a burnished silver contact without copper appearance at more than one location. If copper is visible at more than one location per pole, or the silver is torn on the lower contact block, the interrupter should be replaced. The sliding contact finger assemblies on the PowlVac circuit breaker are reversible. Since only the upper ends of the fingers experience any wiping action, the wear is normally confined to that end. If the upper ends of the fingers show noticeable wear, the finger assemblies should be reversed. Loosen the bolt holding the rear mounting clip and remove the finger assembly. Tighten the bolt holding the rear mounting clip. If copper is visible at more than one contact location on a finger assembly, that assembly should be replaced. Apply a light coat of Mobilgrease 28 contact lubricant to both sides of the contact blocks and to the contact areas of the lower primary disconnects, then reassemble the sliding contact fingers. 3. Vacuum Integrity Refer to section on vacuum integrity and testing interrupters. (Refer to section IV. D.3.) Vacuum interrupters used in PowlVac circuit breakers are highly reliable interrupting elements. Satisfactory performance of these devices is primarily dependent upon the integrity of the vacuum in the chamber and internal dielectric strength. Both these parameters can bereadily checked by a AC high potential test. There are several factory adjustments in the interrupter area, which are described in the supplemental instructions for each particular rating of circuit breaker. No adjustment of these settings is required for routine maintenance. The dimensions given in the supplements are for new interrupters, and all of them will change during the life of the interrupter. Adjustment of these settings will be required only after interrupter replacement. DO NOT ADJUST THESE SETTINGS UNNECESSARILY AS DAMAGE TO THE CIRCUIT BREAKER MAY RESULT. If major disassembly of the mechanism or the vacuum interrupters becomes necessary for any reason, all of the dimensions found in the supplemental directions must be measured and recorded prior to disassembly if interrupter replacement is not required. These dimensions must be restored to the as-found condition upon reassembly to insure proper timing and operation of the circuit breaker. POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 33

34 IB PowlVac Type PVDST Circuit Breaker D. OPTIONAL MAINTENANCE PROCEDURES 1. High Potential Tests These tests are not ordinarily required for routine maintenance, but should be performed after a heavy fault interruption or after the circuit breaker has been in storage for an extended time, especially in a damp location or other adverse environment. Both the High Voltage Insulation Integrity and Control Voltage Insulation Integrity tests should be performed. See the section of this instruction bulletin headed PUTTING INTO SERVICE for details of these procedures. 2. Primary Resistance Check This check is not required for routine maintenance, but it is recommended after any major maintenance, that requires disassembly of any part of the primary current path, except for the sliding contact finger assemblies. This check should be performed after the replacement of a vacuum interrupter assembly. To check the resistance, pass a minimum of 100A DC through the circuit breaker pole, with the circuit breaker closed. Measure the voltage drop across the primary contacts and calculate the resistance. The resistance shall not exceed the values provided for the specific class, type, and rating of the circuit breaker being measured. When making this test, be sure that the test current passes through both main horizontal primary disconnect devices of each pair, or the resistance measurement will be affected. This may be done by connecting the current source leads to two blocks of full round edge copper 1 inch thick by 3 or 4 inches wide by 4 inches long, and pressing these blocks into the upper and lower primary disconnect devices of the circuit breaker. The blocks should be silver- or tin-plated to simulate the primary disconnect devices in the circuit breaker compartment. The voltage drop measurement may be made between these two blocks. For the primary resistance, a data copy can be supplied upon request by notifying the nearest representative of Powell Electrical Manufacturing Company at Powell Apparatus Service Division (PASD). The website is or call POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA

35 PowlVac Type PVDST Circuit Breaker IB VI. RECOMMENDED RENEWAL PARTS AND REPAIR PROCEDURES A. ORDERING INSTRUCTIONS 1. Order Renewal Parts from Powell Apparatus Service Division (PASD). The website is located at or call Always specify complete nameplate information, including: a. Type b. Serial Number c. Rated Voltage d. Rated Amps e. Impulse Withstand f. Control Voltage (for control devices and coils) 3. Specify the quantity and description of the part, and IB If the part is in the tables of recommended renewal parts, give its catalog number. If the part is not in the tables, the description should be accompanied by a marked illustration from this bulletin, a photo, or a sketch showing the part needed. 4. Standard hardware, such as screws, bolts, nuts, washers, etc., should be purchased locally. Hardware used in bolted joints of conductors must be SAE Grade 5 or better in order to insure proper clamping torque and prevent overheating of the joints. Hardware should be plated to deter corrosion. B. RECOMMENDED RENEWAL PARTS It is recommended that sufficient renewal parts be carried in stock to enable the prompt replacement of any worn broken or damaged parts. A stock of such parts minimizes service interruptions caused by breakdowns and saves time and expense. When continuous operation is a primary consideration, more renewal parts should be carried, the amount depending on the severity of the service and the time required to secure replacements. Spare or replacement parts that are furnished may not be identical to the original parts, since improvements are made from time to time. The parts which are furnished, however, will be interchangeable. Tables II, III and IV list the recommended spare parts to be carried in stock by the user. The recommended quantity is not specified. This must be determined by the user based on the application. As a minimum, it is recommended that one set of parts be stocked per ten circuit breakers or fraction thereof. Powell Electrical Manufacturing Company recommends that only qualified technicians perform maintenance on these units. If these circuit breakers are installed in a location where they are not maintained by a qualified technician, a spare circuit breaker should be on site ready for circuit breaker replacement. The malfunctioning unit can then be returned to the factory for reconditioning. POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 35

36 IB PowlVac Type PVDST Circuit Breaker Table II. Vacuum Interrupter and Sliding Contact Finger Assemblies Breaker Type Rated kv Rated Continuous Current RatedShort Circuit Current ka Vacuum Interrupter Assembly [3 per Bkr.] (1) Sliding ContactFinger Assembly [6 per Bkr.] 15PV36DST A G01 P 50952G01 P 15PV36DST A G01 P 50952G01 P Notes for Table ll. The numbers in ( ) indicate that there is a reference note from below. 1. When replacing a vacuum interrupter assembly, specify the part number located on the vacuum interrupter bottle, this will help determine the vacuum interrupter assembly for the circuit breaker. a. For the interrupter assembly 60500G01P, the part number on the vacuum interrupter bottle is Table lll. Control Devices (1) Control Closing Voltage Coil 24VDC N/ A 3 cycle or 5 cycle Primary Shunt Secondary Shunt UnderVoltage Charging Trip Coil(2) Trip Coil (3) Device (4) Motor 50041G05P 50042G06P 50028G08P N/ A Anti-Pump Relay N/ A 48VDC 50026G01P 50041G01P 50042G01P 50028G07P 50960G06P RR2BA-US-DC 48V 125VDC 50026G03P 50041G02P 50042G03P 50028G06P 50960G04P RR2BA-US-DC 110V 250VDC 50026G04P 50041G03P 50042G04P 50028G05P 50960G05P RR2BA-US-DC 110V 120VAC 50026G01P 50041G01P 50042G01P 50028G09P 50960G04P RR2BA-US-AC 120V 240VAC 50026G02P 50041G06P 50042G02P N/ A Capacitor Trip (6) N/A 50041G04P N/ A N/ A 50960G05P RR2BA-US-AC 240V N/ A N/ A Notes for Table III. The numbers in ( ) indicate that there is a reference note from below. 1. One required per circuit breaker, if the circuit breaker was originally equipped with this item. All circuit breakers have closing coil, primary shunt trip coil, charging motor, and anti-pump relay. Secondary shunt trip coils and undervoltage devices are optional. See note Primary shunt trip coil. 3. Secondary shunt trip coil cannot be furnished with undervoltage device, 4. Where furnished, cannot be present with secondary shunt trip coil. Consult factory for part numbers for secondary shunt trip coil devices. 5. For 250VDC applications, a dropping resistor, 50747G02, is required in series with this relay s coil. 6. For use with capacitor trip units with 240VAC input. Consult factory for other circuit breaker ratings. 36 POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA

37 PowlVac Type PVDST Circuit Breaker IB Table IV. Miscellaneous Parts Catalog No. Description Breaker Type Qty. per Brk. Illustration 15PV36DST 750MVA, 1200A 15PV36DST 750MVA, 2000A 1 Auxiliary Switch Assembly (LN: Ring Lugs) (LP: Slip-on Lugs) LN LP LN LP 1 2 Bus Boot 1579B 1579B 3 3 Insulating Pole Support 50642G G Latch Check Switch BA-2RV2-A2 BA-2RV2-A2 1 5 Main Closing Spring Assembly 60217G G Main Insulating Support (Wishbone) 50643G G Manual Charging Handle 50235P P Motor Cutoff Switch Assembly 50756G03P 50756G03P 1 POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 37

38 IB PowlVac Type PVDST Circuit Breaker Table IV. Miscellaneous Parts Catalog No. Description Breaker Type Qty. per Brk. Illustration 15PV36DST 750MVA, 1200A 15PV36DST 750MVA, 2000A 9 Motor Limit Switch BA-2RV-A2 BA-2RV-A PowlVac Hardware Kit 60500G G PowlVac Lubrication Kit Consisting of: (2 oz Anderol 456 Needle Application) (2 oz Rheolube 368A Tube) (2 oz Mobil 28 Tube) Powlube-102 Powlube Operating Pushrod Assembly 50934G G Racking Handle 50218G G Shock Absorber (Dashpot) 50735G G Vacuum Integrity Tester 60900G G Wheel POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA

39 PowlVac Type PVDST Circuit Breaker IB C. REPLACEMENT PROCEDURES This section includes instructions for replacing all the parts recommended as renewal parts. Before attempting any maintenance repair work, take note of safety practices outlined in Section II of this bulletin. MAKE CERTAIN THAT THE CONTROL CIRCUITS ARE DE-ENERGIZED AND THE CIRCUIT BREAKER IS RESTING SECURELY OUTSIDE THE SWITCHGEAR HOUSING. DO NOT START TO WORK ON A CLOSED CIRCUIT BREAKER OR A CIRCUIT BREAKER WITH THE CLOSING SPRING CHARGED. WHEN ANY MAINTENANCE PROCEDURE REQUIRES OPENING OR CLOSING OF THE CIRCUIT BREAKER OR CHARGING OF ANY OF THE MECHANISM SPRINGS, EXERCISE EXTREME CARE TO MAKE SURE THAT ALL PERSONNEL, TOOLS, AND OTHER OBJECTS ARE KEPT WELL CLEAR OF THE MOVING PARTS OR THE CHARGED SPRINGS. 1. Vacuum Interrupter Assembly Refer to the applicable Vacuum Interrupter addendum. 2. Sliding Contact Finger Assembly Instructions are given in the maintenance section of this instruction bulletin for removing and inverting the sliding contact finger assembly. Follow these instructions, but install the new finger assembly instead of reinstalling the old one. See figure 1 [w] to replace it. 3. Closing Coil Assembly The closing coil is located in the lower front center of the circuit breaker. See figure 4 [k] to replace it: a. Remove front cover of the circuit breaker. b. Disconnect the closing coil from the wire harness. c. Remove two bolts holding closing coil assembly to base pan and drop the closing coil out of the bottom of the circuit breaker. d. Insert new closing coil assembly into the circuit breaker from below, bolt it in place and connect into the wiring harness. No adjustment is required. e. Close circuit breaker several times electrically to insure that coil is functioning properly. f. Replace front cover. POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 39

40 IB PowlVac Type PVDST Circuit Breaker 4. Primary Shunt Trip Coil Assembly This assembly (fig 4 [e]) is located in the center part of the mechanism area, just to the left of the main closing spring. a. Remove front cover of circuit breaker. b. Disconnect the trip coil from the wiring harness. c. Remove the two bolts holding the trip coil assembly to the circuit breaker frame and remove the assembly. d. Bolt the new assembly in place and connect into the wiring harness. e. With the circuit breaker mechanism in the reset position, check the gap between the trip coil armature and the trip lever extending from the trip shaft. This gap should be between 1/4 inch and 5/16 inch. If necessary, bend the trip lever slightly to achieve this setting. f. Trip the circuit breaker electrically several times to insure that coil is functioning properly. g. Replace front cover. 5. Secondary Shunt Trip Coil Assembly This assembly is located in the center part of the mechanism area, just to the right of the main closing spring. The replacement procedure is identical to that of the primary shunt trip coil, with the following additional information: Note: It will be easier to remove the trip coil assembly if the right hand main operating spring connecting rod is removed. See section headed Closing Spring Removal and Slow Closing of Mechanism under Maintenance in this instruction bulletin for removing this connecting rod. 6. Undervoltage Device Assembly This assembly is located in the center part of the mechanism area, just to the right of the main closing spring. a. Remove front cover. b. Remove right hand main operating spring connecting rod. See section headed Closing Spring Removal and Slow Closing of Mechanism under Maintenance in this instruction bulletin for procedures for removing this rod. c. Disconnect the undervoltage device from the wiring harness. d. Remove the two bolts holding the undervoltage device assembly to the circuit breaker frame and remove the assembly. e. Bolt new assembly in place. f. Reassemble the main operating spring connecting rod. g. While the undervoltage device has been tested at the factory, it is necessary to check and possibly adjust its settings once it has been assembled to the circuit breaker. This will require a variable voltage DC source capable of output of from 40% to 100% of the DC rating of the undervoltage device. Connect this source to the terminals of the undervoltage device coil. Apply a DC voltage of 80% of the undervoltage coil rating. The undervoltage device should pick up and allow the circuit breaker to close. Close and trip the circuit breaker several times, using manual or shunt trip, to be sure that the vibration of circuit breaker operation does not cause the undervoltage device to drop out improperly. If the device does drop out during this test, rotate the screw at the bottom of the device to the right in 1/8-turn steps until proper operation is obtained. This adjustment may be fine turned by bending the tab at the base of the beam spring up in 1/8-inch steps. Check dropout of undervoltage device by reducing test voltage to 52-56%. The undervoltage device should drop out and cause the circuit breaker to trip in this voltage range. If dropout voltage is too low, bend the tab at the base of the beam spring down slightly to raise the voltage. h. Disconnect the test source and connect the undervoltage device into the wiring harness. i. Replace front cover. 40 POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA

41 PowlVac Type PVDST Circuit Breaker IB Charging Motor Assembly The charging motor assembly is located at the lower right hand side of the mechanism See figure 4 [t] to replace it: a. Remove front cover of the circuit breaker. b. Disconnect the motor from the wiring harness. c. Remove the two bolts holding the motor mounting bracket to the base pan and slide the motor to the right, disconnecting the motor shaft from the mechanism, and lift the motor out. d. Lubricate the end of the shaft of the new motor liberally with Rheolube 368A grease. e. Position the new motor assembly in the circuit breaker, being sure that the pin on the end of the drive shaft engages the slot in the mechanism shaft. f. Bolt the motor to the base pan and connect it into the wiring harness. g. Operate the circuit breaker several times to insure that the motor operates smoothly. h. Replace the front cover. 8. Anti-Pump Relay Assembly This relay is located near the top of the mechanism, to the right of the opening springs. a. Remove the front cover of circuit breaker. b. Disconnect the wires from anti-pump relay assembly, being careful to note which wires go to which terminal. c. Remove the mounting screws of the mounting bracket of the assembly and remove the assembly from the circuit breaker. d. Remove the anti-pump relay from the mounting bracket by removing the retaining clip from the anti-pump relay. e. Insert the new anti-pump relay back into the mounting bracket, and fasten the retaining clip to the anti-pump relay. f. Reconnect all wires to the proper terminals of the relay. g. Relays in 250VDC closing circuits are provided with dropping resistors to apply the proper voltage to the relay coil. The resistor is mounted adjacent to the relay. It may be replaced by disconnecting it from the relay and unscrewing the mounting feet from the circuit breaker frame, replacing the resistor and reassembling. h. Operate the circuit breaker several times to insure the relay functions properly. i. Replace the front cover. 9. Latch Check Switch Assembly The latch check switch is located on the left-hand side of the main mechanism frame, near the bottom of the main closing spring. See figure 4 [q] to replace it: a. Remove front cover of circuit breaker. b. Remove two screws holding switch to mechanism. Do not loosen the nut plate into which these screws are threaded. c. Disconnect wires from switch. d. Connect wires to new switch and fasten switch in place with screws and nut plate previously removed. e. Adjust switch see the instructions in section headed Adjustment of Primary and Secondary Trip Latches and Latch Check Switch under MAINTENANCE in this instruction bulletin. f. Operate circuit breaker electrically several times to insure that it is working. g. Replace front cover. POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 41

42 IB PowlVac Type PVDST Circuit Breaker 10. Motor Cutoff Switch Assembly The motor cutoff switch assembly is located of the floor pan of the mechanism area, just to the right if the main mechanism. See figure 4 [u] to replace it: a. Remove front cover of circuit breaker. b. Disconnect wires from switch, being careful to identify each wire by the terminal number from which it was removed. c. Remove the two bolts holding the assembly to the circuit breaker floor pan and remove assembly. d. Install new cutoff switch assembly; bolt it to the floor pan. Reconnect the wiring. No adjustments are needed. e. Operate the circuit breaker electrically several times to insure that it is working. f. Replace front cover. 11. Auxiliary Switch Assembly The auxiliary switch is located on the lower left front of the mechanism area. See figure 4 [d] to replace an auxiliary switch: a. Remove front cover of circuit breaker. b. Disconnect wires from switch, being careful to identify each wire by the terminal number from which it was removed. c. Remove the E ring securing the switch operating arm to the operations counter linkage. d. Remove the two screws holding the auxiliary switch to its mounting bracket, and remove the switch. e. Insert new switch and attach it to the mounting bracket with the two screws removed in step d. f. Insert the operating arm of the switch in to the hole in the end of the operations counter linkage and secure with the E ring removed in step c. g. Reconnect the wiring. Be sure wires are connected to the same terminals from which they were removed. h. Operate circuit breaker electrically several times to insure that it is working. i. Replace front cover. 42 POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA

43 PowlVac Type PVDST Circuit Breaker IB Vll. ANNEX A. COMMISSIONING FOR REPLACEMENT CIRCUIT BREAKERS It is essential that both classroom and hands-on equipment training accompany any installation of a new replacement, retrofill, or retrofit circuit breakers. The operator and maintenance technicians must be trained in all tasks, which they are expected to perform task relating to operation and maintenance of the equipment. They must also be trained in how the circuit breaker must properly interface with the existing metal-clad switchgear. In addition to training, a check out must be performed to confirm that the circuit breaker was not damaged in shipment, and is compatible with the existing cell. During this check out, adjustments may be required to match the two devices. A physical inspection and mechanical checkout of the circuit breaker and cell must be performed to confirm that the new circuit breaker s nameplate is consistent with the existing metal-clad switchgear rating, and that the circuit breaker and cell are functioning separately. Typically, these tests should include all tests recommended in the circuit breaker manufacturer s instruction bulletin. As a minimum, the circuit breaker should undergo an inspection, functional checks, a circuit breaker timing test, and a vacuum integrity test (with a vacuum integrity tester or an ac high potential tester). Moreover, a high potential test of the circuit breaker is required to assure phase to phase and phase to ground dielectric integrity. Once these checks are completed, confirm that the replacement breaker properly racks into and out of the cell. The replacement circuit breaker has been designed to be compatible with the existing cell, but checks must be made to fit the circuit breaker with the specific metal-clad switchgear compartment. For example, this may require the adjustment of the front cover to minimize gaps and overlaps. Once the replacement circuit breaker cover matches up to the existing equipment, the ground shoe (connection) and primary disconnects should be checked to confirm that the circuit breaker is engaging the metal-clad switchgear fully. To confirm the circuit breaker s engagement, apply a very thin layer of the manufacturers recommended stab grease to the circuit breaker s connections. De-energize the metal-clad switchgear and rack the replacement circuit breaker in and out of the cell without closing the circuit breaker. Inspect the primary stabs and the ground shoe (circuit breaker ground connection) for uniform distribution of the lubricant. If the metal-clad switchgear can remain deenergized for the time needed, the insertion test can be followed by a ductor test (dc resistance test) from the line side to load side of each cell. With the circuit breaker installed and closed, confirm resistance and assure that the primary disconnects are in good contact with the metal-clad switchgear compartment. This step is impossible if the metal-clad switchgear cannot be de-energized, but it is important to remember that the circuit breaker primary disconnects are only part of the total current path. Even though the circuit breaker may be in new condition, if the contact surfaces in the metal-clad switchgear are dirty or corroded the resulting connection between the circuit breaker and metal-clad switchgear may be highly resistive. Consequently, this will lead to the overheating of the connection, and a possible premature failure of the connection. Once the ground shoe connection and primary disconnects have been checked, the secondary control disconnect should be checked to confirm that the metal-clad switchgear secondary disconnect engages properly and that the metal-clad switchgear compartment wiring matches the replacement circuit breakers. The control wiring of some of the older solenoid operated circuit breakers and metal-clad switchgear may need modification in order for the new, stored-energy mechanism to operate properly. Some equipment designs and control schemes do not have a steady-state control voltage available at the secondary disconnect that is required for the stored energy feature to operate. This is predominately true for designs that have the closing, or X relay mounted in the metal-clad switchgear compartment. In the external closing relay designs, the closing power was POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 43

44 IB PowlVac Type PVDST Circuit Breaker only applied momentarily to the circuit breaker, simply long enough for the circuit breaker to close and latch. Normally the power is removed upon completion of the closing operation by the action of a circuit breaker s mounted cutoff switch that deenergizes the X directly, or energizes the anti-pump, or Y relay which in turn deenergizes the X. The preferred method for supplying the required charging power to the circuit breaker is the use of unused spare auxiliary contact secondary disconnects. The ultimate goal in a multi unit replacement is to identify a common terminal in all circuit breaker compartments in order to maintain interchangeability between the replacement circuit breakers themselves, and also between the old circuit breakers if interchangeability with the existing circuit breaker is required. If this cannot be achieved, a blocking or rejection feature must be added or modified to prevent interchange of the circuit breakers. It has also been a field practice to install a jumper around the normally open X contact to supply steady state power to the circuit breaker. If this is done, inserting the original circuit breaker into the modified compartment may result in the unintentional closing of the circuit breaker. This presents a hazardous condition that must be avoided by modifying the blocking or rejection features to prevent insertion of the old circuit breaker into the modified compartments. It should also be noted that most of the old solenoid operated circuit breakers requires substantially higher current to operate than that of the requirements of a replacement circuit breaker. This means that the control fuses in the closing circuit were normally 60 amps or greater. It is also prudent to protect the charging motor circuit with fuses appropriate for this load. These fuses can either be integral to the replacement circuit breaker, or located upstream in the metal-clad switchgear cubicle. The original circuit breaker may also have tripping current requirements far above the requirement of the replacement circuit breaker. These trip coils were normally wound with larger wire in order to accommodate the higher current. Due to the higher thermal capability of these coils, fairly high trickle currents flowing in these coils for healthy coil monitoring could be tolerated without damage to the coil or any negative impact on circuit breaker operation. This may not be the case with the replacement circuit breaker. In a worst case, excessive current flowing through the trip coil may overheat the coil or cause partial operation of the coil. Either of these may negatively affect proper circuit breaker operation. Control circuit coordination of the new replacement circuit breaker and the old circuit breaker must be carefully considered in cooperation with the user and manufacturer in order to assure long-term proper operation of the replacement circuit breakers. Also, relay target setting should be reviewed to insure that the targets will operate by the reduced trip current of the new circuit breaker. The last step is to verify that the insertion and withdrawal interlock functions must be verified. Although these interlocks are normally adjusted and checked at the factory, the existing compartment may not be within originally specified tolerances. Deviation from originally specified dimensions may be due to wear, original installation deviations to specification, or field modifications made throughout the service life of the equipment. Adjustments may be required to the circuit breaker and/or the compartment to ensure proper operation of these critical interlocks. For further details, contact Powell Electrical Manufacturing Company. 44 POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA

45 PowlVac Type PVDST Circuit Breaker IB Table V. Trouble Shooting Topics Problem Possible Cause Reason & Remedy Mechanism does automatically Breaker will not Breaker will not Breaker opens not charge close trip closes and instantly N o Control Voltage Improper wiring or missing fuses in control circuit. Replace fuses or correct wiring and verify control voltage at secondary disconnect. S econdary disconnect Secondary disconnect not seated properly. Ensure proper connection of secondary disconnect. C ircuit breaker internal control Circuit breaker internal control circuitry not completed. Refer to the circuit breaker's control schematic to verify proper operation of all internal components. Verify the integrity of the control wiring. No control power at closing Control power not present at closing coil. coil Verify operation and integrity of all control devices and wiring.repair and replace defective control devices and wiring as necessary. C lose latch Close latch not properly adjusted or lubricated. Adjust closed latch properly and lubricate. See Mech. Adj., section No control power at closing Control power not present at closing coil. coil Verify operation and integrity of all control devices and wiring. Repair and replace defective control devices and wiring as necessary. Lubrication Circuit breaker lacks lubrication within the mechanis m area. Lubricate the circuit breaker as needed. See the maintenance section for proper lubrication methods shown in your instruction bulletin. Protective devices Fault in HV power circuit and protective relay functions tripping breaker. Check circuit and remove fault.nuisance tripping from protective relays.adjust protective device parameters. Manual trip linkage Manual trip linkage binding and not allowing opening cam to fully reset. Check opening cam for free movement and travel. Cam should reset and seat on roll pins against opening cam housing. POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 45

46 Index A, B Adjustments close latch 29 latch check switch 29 primary and secondary trip latches 29 ratchet wheel holding pawl 29 Annex commissioning 43 Anti-pump relay 18 C, D Cam and fundamental linkage positions 13 Circuit breaker inserting into switchgear 24 Control circuit operation sequence 19 typical DC control scheme 18 E, F Electrical operation 29 G, H Ground contact 11 I, J, K Installation handling 20 receiving 20 storage 20 Instruction bulletin conflict with other documents 5 other items of caution 5 purpose 5 scope 5 website information 6 Interlocking cell interlocks 17 levering-in interlock 16 L Levering-in device 11 Levering-in interlock 16 Lubrication description 27 illustrations 31, 32 M, N Maintenance description 26 inspection and cleaning 27 Maintenance schedule 26 Mechanism and trip linkages 13 Mechanism area adjustments 29 description 27 electrical operation 29 lubrication 27 main closing spring installed 28 main closing spring removed 28 mechanical operation 27 slow closing of mechanism 28 Miscellaneous parts replacement assemblies 37, 38 Motor cutoff switch 17 O Operating solenoids 17 Optional maintenance procedures high potential tests 34 primary resistance check 34 P, Q Placing into service control voltage insulation integrity 23 description 22 high voltage insulation integrity 22 vacuum integrity 22 Powell Apparatus Service Division 6, 26, 35 information 22 Powell Electrical Manufacturing Company 6 Primary resistance check 34 Putting into service commissioning 22 control voltage insulation integrity 23 description 22 dimensional check 23 electrical operation 23 high voltage insulation integrity 22 mechanical operation check 23 vacuum integrity 22 PVDST description 9 exterior component illustrations 12 interior components illustrations 14 R Renewal parts control devices 36 description 35 miscellaneous parts 37, 38 ordering instructions 35 sliding contact finger assembly 36 vacuum interrupter assembly 36 Replacement procedures anti-pump relay assembly 41 charging motor assembly 41 closing coil assembly 39 latch check switch assembly 41 motor cutoff switch assembly 42 primary shunt trip coil assembly 40 secondary shunt trip coil assembly 40 sliding contact finger assembly 39 undervoltage device assembly 40 vacuum interrupter assembly 39 Rollout truck 11 S Safety 6 Safety labels 8 Secondary contacts 24 Shutter lift 15 Stored energy mechanism 9 T, U Testing AC or DC high potential test (hipot) 22, 23 Trouble shooting topics 45 V Vacuum interrupter and contact area sliding contact finger wear 33 vacuum integrity 33 vacuum interrupter contact erosion 33 Vacuum interrupters 17 W Website 6, 35 X X relay 43 X-rays 7 Y, Z Y relay POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA

47 Notes POWELL ELECTRICAL MANUFACTURING COMPANY, HOUSTON, TEXAS, USA 47

48 November 2001 POWELL ELECTRICAL MANUFACTURING COMPANY 8550 MOSLEY DRIVE HOUSTON, TEXAS USA PHONE (713) FAX (713) POWELL ELECTRICAL MANUFACTURING CO. All Rights Reserved.