A Practical Guide to Maximizing Machine Uptime

Transcription

1 A Practical Guide to Maximizing Machine Uptime Every day, maintenance professionals across the world face the challenge of pushing maximum machine potential while at the same time, keeping repairs at a minimum a challenge that is difficult to accomplish. Thankfully, there is a solution that opens the door to reliability predictive maintenance technology.

2 E very day, maintenance professionals across the world face the challenge to maintain maximum machine uptime while reducing costly downtime a challenge that is difficult to accomplish. Predictive maintenance programs can accomplish this predicament with low investment requirements. Predictive maintenance services help determine the condition of in-service equipment in order to predict when maintenance should be performed. This approach offers savings over routine maintenance since tasks are only performed when needed. The main value of predictive maintenance is to allow the convenience of scheduling corrective maintenance ahead of time. Additionally, this allows one to prevent unexpected equipment failures. Benefits may include: Increased equipment lifetime Increased plant safety Optimized spare parts handling Lower maintenance costs Reduced machinery downtime Increased production There are three types of machinery maintenance: 1. Reactive 2. Preventative 3. Predictive Reactive maintenance is really no maintenance at all run your equipment until you experience a total failure. The problem with this technique is that failures are often untimely and more expensive to deal with. Not to mention, some failures can result in a complete disaster to your business. That s where preventative maintenance comes in. Preventative maintenance involves periodic disassembly, full inspection and replacement of worn parts to prevent a future disaster from occurring. By doing so, you ll experience a lower frequency in breakdown repairs and shutdowns. Furthermore, this leads into predictive maintenance which involves the trending and analysis of a machine s current condition to detect and identify developing problems before experiencing equipment failure. Predictive programs help get the maximum performance out of a machine before end of life. By monitoring and diagnosing problems ahead of time, you can significantly increase the life and productivity of your equipment before a catastrophic failure may occur.

3 The ultimate goal of predictive maintenance is to perform maintenance at a scheduled point in time when the maintenance activity is most cost-effective; prior to performance loss. The predictive component derives from the goal of predicting the future trend of the equipment s condition. In order to achieve maximum productivity and minimize disruption of normal operations, predictive maintenance inspections are performed while equipment is in use. An integral part of predictive maintenance is analysis and reporting. It s important to be able to track equipment performance factors to fully utilize predictive maintenance for what it s worth. Predictive Maintenance Technologies To evaluate equipment condition, predictive maintenance utilizes nondestructive testing technologies such as: Infrared Thermography Oil Analysis Vibration Analysis Dry-ice Blasting Motor Circuit Testing Predictive Maintenance Services Offered through ACT/Whelco: Turnkey services Vibration Analysis Motor Circuit Testing Online Analyzer Laser Alignment Coupling Inspections Belt Tensioning Field Balancing Cryogenic Dry Ice Cleaning On-sit Winding Analysis DC Brush Maintenance Oil Sampling Infrared Thermography On-site Installation/Removal Bearing Replacement- Sleeve and Rolling Elements Infrared Thermography Infrared monitoring and analysis can be used from low-speed equipment to high-speed equipment, and can be effective for spotting both electrical and mechanical failures. Oftentimes, infrared has been said to be the most cost-effective technology available. Infrared technology can be defined as the process of generating visual images that represent variations of IR radiance of surfaces of objects. IR radiation falls outside that of visible light and therefore, it s invisible to the naked eye. However, an IR camera or similar device allows us to escape the visible light spectrum and view an object based on temperature. Why is this important? Similar to other predictive maintenance technologies, IR attempts to detect the presence of stressors or conditions that will decrease the life of your equipment.

4 For example, rotating equipment problems are normally the result of frictional changes that can be detected in the thermal profile. The following list contains just a few of the possible : Transmission lines Splices Shoes/end bells Inductive heating problems Insulators Cracked or damaged/tracking Distribution lines/systems Splices Line clamps Disconnects Oil switches/breakers Capacitors Pole-mounted transformers Lightning arrestors Imbalances Substations Disconnects, cutouts, air switches Oil-illed switches/breakers (external and internal faults) Capacitors Transformers Internal problems Bushings Oil levels Cooling tubes Lightning arrestors Bus connections Generator Facilities Generator Bearings Brushes Windings Coolant/oil lines: blockage Motors Connections Winding/cooling patterns Motor Control Center Imbalances In-Plant Electrical Systems Switchgear Bus Cable trays Batteries and charging circuits Power/Lighting distribution panels The following list provides a few Steam Systems Environmental Boilers Water discharge patterns Refractory Air discharge patterns examples: Tubes Motors and rotating equipment

5 Traps Bearings Valves Mechanical failure Lines Improper lubrication Heaters and furnaces Coupling and alignment problems Refractory inspections Electrical connections on motors Tube restrictions Air cooling of motors Fluids Vessel levels Pipeline blockages Oil Analysis One of the oldest predictive maintenance technologies still used today is that of oil analysis. Oil analysis is used to define three basic machine conditions related to the lubrication system: 1. The condition of the oil test the viscosity, acidity, etc. 2. The condition of the lubrication system test for water content, silicon, or other contaminants 3. The condition of the machine itself analyze wear particles existing in the lubricant Taking samples from your active, low-pressure line ahead of any filtration devices is a good way to indicate the condition of the oil, lubrication system and machine. For consistent results and accurate trending, be sure to take samples from the same place in the system each and every time. A full analysis will help determine the condition of the lubricant, excessive wearing of oilwetted parts and the presence of contamination.

6 Vibration Analysis Abnormal levels of vibration can cause equipment failure without proper analysis. Vibration, as defined in the dictionary a periodic motion of the particles of an elastic body or medium in alternately opposite directions from the position of equilibrium when that equilibrium has been disturbed or the state of being vibrated or in vibratory motion as in oscillation or a quivering or trembling motion. The important factor in this definition is that vibration is motion. As this motion continues to build up, the level of frequency can change and is undetectable by human touch. In order to obtain valuable data about equipment vibration, we use vibration detection instruments and signature analysis software. We use sensors to quantify the magnitude of vibration and convey them in the following three ways: 1. Displacement 2. Velocity 3. Acceleration With a good understanding of machine design and operation, we can interpret the information received from testing to define the machine s problem. Once the information is retrieved, an easy-to-follow report is generated for anyone with basic knowledge to read. Vibration monitoring and analysis can be performed on these types of equipment: Unbalance Eccentric rotors Misalignment Resonance problems Mechanical looseness/weakness Rotor rub Sleeve-bearing problems Rolling element bearing problems Flow-induced vibration problems Gear problems Electrical problems Belt drive problems Analyzing this equipment to determine the presence of bad vibration is not a simple task. Properly performed and evaluated tests require highly trained and skilled individuals.

7 Dry-ice blasting Dry-ice blasting is a form of abrasive blasting where dry ice is accelerated in a pressurized air stream and directed at a surface in order to clean it. Why use dry-ice? Dry-ice leaves no chemical residue as it sublimates at room temperature. Essentially, the sublimation process absorbs a large portion of heat from the surface which produces shear stress due to thermal shock. This is claimed to improve cleaning as the top layer of dirt is expected to transfer heat and flake off very easily. Dry ice cleaning removes the following: Paint/varnish Oil Grease Tar Bitumen Dirt Ink Resin Adhesives Wax Binders and solvents Silicon/rubber residues Chewing gum Graffiti And much more Motor Circuit Testing If you re looking for a full analysis of your motor condition, infrared and vibration will not provide all the answers required to properly diagnose the condition of your motor. Over time, motor circuit testing techniques have become more and more sophisticated. Motor faults such as winding short-circuits, improper torque settings, open coils, etc. can be easily evaluated with professional motor circuit testing. Motor analysis equipment remains fairly expensive and requires a degree of skill and technique. There are two commonly used tests: 1.) Electrical Surge Comparison a. One of the primary concerns of motor condition is winding insulation. Surge comparison testing can be used to properly identify turn-to-turn and phase-tophase insulation deterioration. Due to differences in insulation thickness, motor winding insulation tends to be more susceptible to failure from stress. Surge comparison testing allows us to quickly identify where the deterioration exists by applying a high frequency transient surge to the winding and compare the resulting voltage waveforms. When differences in waveforms exist, this indicates

8 insulation or coil deterioration. 2.) Motor Current Signature Analysis a. Another worthwhile tool in motor circuit testing is motor current signature analysis (MCSA). The benefit of MCSA is that it uses a non-intrusive method for detecting mechanical and electrical problems. The technology is based on the idea that a conventional electric motor driving a mechanical load acts as a transducer. The motor senses the mechanical load variations and then converts them into an electrical current that moves along the motor power cables. These particular currents are reflective of a machine s condition. Motor Circuit Testing Applications: Stem packing degradation Incorrect torque switch settings Degraded stem Worn gear tooth wear Restricted valve stem travel Improper seal installation Inaccurate shaft alignment or rotor balancing Improper bearing or gear installation Obstructions in the valve seat area Disengagement of the motor pinion gear Insulation deterioration Turn-to-turn shorting Phase-to-phase shorting Reversed or open coils Short circuit

9 Conclusion As with most predictive maintenance services, the greatest saving opportunity does not come from preventing a catastrophic failure, but rather the less tangible cost savings benefits. It s important to understand that one, unplanned motor failure can cost more than one year of predictive maintenance services. Reduced downtimes, increased productivity, ability to schedule maintenance, decreased inventory cost and decreased overtime are just a few of the advantages of predictive maintenance services. ACT is first and foremost a service company. We measure our business and success every day on three variables: the quality of our work, our turnaround time, and cost-effective pricing. Our team takes pride in providing excellent customer service to our customers. We understand we are only as good as the service we provide TODAY. When we build a relationship with our customers, we consider it a partnership. Consider ACT when looking for a partner to assist with you industrial repair needs. When your motor or equipment fails, your line goes down and you are losing money, you need a trusted partner who is experienced, diverse and able to address your needs on your schedule. Whether your situation involves critical production downtime and/or a unique technology or process, Whelco is the shoulder you can lean on. For a FREE evaluation and quote on your equipment, contact us via one of the methods below: Phone: sales@act-repair.com Fax: