1. PERFORM VISUAL INSPECTIONS
A quick visual inspection can reveal some important details about the electric motor. Take a look at its physical condition and record your observations. If the electric motor operates in a rugged environment, you will see signs of corrosion and dirt buildup on individual components. Observe the motor’s windings to detect any hint of overheating, such as a burnt odor. Ensure relays and contacts are dust-free and aren’t rusted. All these factors may cause an internal problem as the debris may pose a threat to the efficient performance of the equipment.
2. PERFORM A BRUSH AND COMMUTATOR INSPECTION
Regular maintenance checks help ensure that electric motors won’t experience inconsistencies or stop working abruptly. Look for signs of wear and tear; any hint of excessive wear leads to commutation problems with the motor. This means you need to change the brush in order to regain the integrity of the equipment’s function. Also keep a check on the commutator to ensure it doesn’t have any dents, grooves, or scratches. These rough spots indicate brush sparking. Additionally, inspect the motor mount, rotor, stator and belts thoroughly. Replace all worn out parts.
3. CONDUCT A MOTOR WINDING TEST
Once you have inspected the various machine components, you need to test the motor’s windings. This test helps you identify any anomalies or failures in the windings. If you see any burn marks or cracks or smell a burning odor, conduct a mandatory motor winding test.The test involves disassembling the motor to determine the abnormalities of the motor. If the windings are overheated, the chance of serious damage is higher. Rewinding the motor and testing the wind insulation, which reveals information on the resistance level, are also critical parts of the test.
4. CHECK THE BEARINGS
Check the bearings for noise and vibration as they indicate potential problems, like poor lubrication, dirt buildup, and wear and tear. If the bearing’s housing is too hot to touch, it may mean the motor is getting overheated or there is an insufficient amount of grease. The maintenance requirements for bearings may vary, depending on where the equipment is situated. You need to be aware of the different kinds of bearings being used in the plant and what their repair requirements are.
5. PERFORM VIBRATION TESTS
Sometimes, excessive vibrations are difficult to detect manually. But, if not detected on time, vibration can reduce the life span of an electric motor, which then eventually leads to motor bearing failure or failure of windings. In most cases, the cause of vibration is mechanical in nature, such as a faulty sleeve or ball bearings, too much belt tension, or improper balance. The electric motor can be tested by removing the belts or by disconnecting the load and then operating the motor. Sometimes, even electrical problems can give rise to vibrations. A few tests, such as field vibration analysis that is conducted by mobile instruments that measure exact frequency and amplitude of vibrations, can help in detecting the exact cause of vibrations.
6. USE INFRARED THERMOGRAPHY IN PREDICTIVE MAINTENANCE
Recently, this method of inspection has become popular with predictive maintenance due to its desired outcome. With infrared thermography, an infrared camera is used to capture thermal images without interfering with the motor’s operation. These images provide a temperature profile of the electric motor by giving heat patterns at several points throughout the motor simultaneously. All mechanical systems produce a particular amount of thermal energy, therefore, they have normal thermal patterns along with a maximal temperature at which the motor can work. In case any problem exists, such as insufficient air flow,insulation failure, or degradation in the stator, the infrared camera will immediately detect the unstable voltage in the form of a thermal image, helping you find its cause and solution.
7. DOCUMENT EVERYTHING
Documentation is extremely important. Keep detailed records of all preventive maintenance schedules, tests performed and their results. Maintain records of all repairs and replacements, as well. Doing so allows you to have a better understanding of the equipment, identify which issues need to be addressed, or determine which parts have to be replaced or repaired. Your records also will be helpful for future audits and inspections.
DOCUMENTATION IS EXTREMELY IMPORTANT
Precautions to Take While
Performing Maintenance Checks
Only assign electric motor maintenance tasks to those individuals who are well-trained in handling electrical components. Those who perform this task need to be aware of hazardous situations.
Qualified personnel who perform maintenance checks should be equipped with protective gear, along with dielectric tested gloves and approved electrical test devices.