Facility equipment — especially industrial motors — naturally wear down throughout operation, sometimes to the point of failure.
In order to avoid costly unplanned downtime, plant managers should administer scheduled shutdowns at least once a year. Annual motor maintenance not only lengthens equipment life — it also decreases energy consumption.
These planned shutdowns allow for comprehensive testing and tune-ups for all motors and machinery, identifying potential issues and replacing parts as needed.
At Renown Electric, our experts are heavily involved in planned shutdowns, many of which occur during the summer months. We regularly visit plants during their planned shutdowns as part of scheduled preventative maintenance (PM) programs to run an array of sophisticated tests that reduce or eliminate motor failures.
Below are some of the most common issues associated with equipment failure that should be on your maintenance checklist.
1. Vibration Analysis
Vibration analysis is the most common technology used for testing the health of a motor. Advanced equipment analyzes the vibration signals (or signatures) that generate from rotating equipment.
Experts examine the patterns of these signals and compare them to baseline data taken at initial machine start-up. Excessive vibration generally indicates a problem exists, with some of the most common sources being bearing failure, imbalance, and misalignment, among others.
2. Bearing Malfunction
More than half of all motor failures originate in problems with bearings. A worn, over-lubricated, or under-lubricated bearing will vibrate excessively — especially before an equipment failure.
After detecting a potential bearing issue, maintenance professionals can determine and treat the exact source of the problem. Solutions include rotating motors to avoid denting bearings, ensuring proper installment and fit, and providing proper lubrication and effective seals.
3. Unbalanced or Overload Voltage
Handheld infrared devices help detect hotter-than-average motor temperatures and capture two-dimensional images. Increased temperatures often signify unbalanced or overloaded voltages. Thermal images and temperatures taken during normal operating conditions should be compared to readings taken while testing.
When necessary, a researcher can identify and correct the potential causes of unbalanced or overloaded voltages. Some of these include hotspots in winding connects, short circuits in a coil, or possibly a broken or cracked motor shaft or rotor.
4. Motor Drive Alignment
Misalignment occurs when motor shafts and their respective pumps, generators, or other plant systems are not properly aligned. This condition creates excessive and rapid wear on bearings and harsh effects on belt drives. Misaligned motors also increase friction on a shaft, making it difficult to turn and wasting energy.
The overall impact of misalignment ranges from downtime and lost production to fire safety hazards. Advanced laser measuring equipment can easily detect misalignment and should be regularly checked to ensure smooth motor operation.
5. Motor Winding Analysis
Problems in electrical equipment often cause unscheduled shutdowns and sometimes catastrophic failures. Electrical motor winding analysis (MWA) is a non-destructive testing technique that enables early detection of difficulties in electrical equipment.
MWA covers windings in motors, transformers, generators — virtually any electrical component. It can be applied to AC, DC, and synchronous motors while the equipment is out of operation, ensuring the strength of winding insulation and indicating where repairs are needed.
6. Motor Balancing
Out-of-balance motors are generally easy to detect: upon start-up, motors with balancing issues cause excessive vibration and noise that tends to increase with the speed of the motor’s operation.
If not dealt with quickly, off-balance motors can precipitate bearing wear, structural damage, and possible equipment failure.
While some plant operators send motors to manufacturers to correct this problem, on-site dynamic balancing has many advantages. It is faster, less expensive, and allows for compensation in its surrounding components during and after repairs.
Examining the content and contamination of oil provides excellent information about the state of the motor itself. The wear from a motor’s moving parts emits particles into the oil. Measuring the oil’s contamination, oxidation, and viscosity on a regular basis reveals the rate of wear the motor is undergoing and can highlight issues like current running through the bearings.
Oil sampling should be part of every company’s testing during scheduled maintenance, allowing for the health of the machine to be effectively monitored at minimal costs.
Physical contamination can also be a major problem. Motors that run in environments where airborne contaminants fall on motors will create an unwanted insulation layer. This layer of waste does not allow the motor to vent heat properly leading to motors overheating and failing prematurely. Consider dry-ice cleaning or other methods to eliminate the layer of built up materials on motors to allow for effective heat transfer and longer operating life.
Ongoing Preventative Maintenance Tips
In addition to scheduled shutdowns, the following represent a few preventative maintenance steps that can help maximize the safety and efficiency of your equipment’s operation.
– Lubricate equipment regularly
– Inspect bearings at a predetermined schedule
– For heavy duty motors, check bearings regularly
– Check belt tension
– Inspect DC motors’ brushes and commutators
– Check contacts for pitting and indications of overheating
– Keep accurate records
Performing an annual shutdown for diagnostics and preventative maintenance can have a profound impact on the safe and efficient operation of your plant. At Renown Electric, we have the experience and expertise to ensure your maintenance is completed comprehensively and at the highest levels of accuracy. We also have spare motor parts for any replacements you require.
For further questions or to schedule one of our experts for your shutdown, contact us today.