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