Long and unscheduled downtime in today’s industries is not only troublesome but also cuts deeply into the profits of the companies. Hence the need for effective Preventive Maintenance (PM) programs on electric motors arises. Regular and timely maintenance of electric motor ensures long- life and makes them resilient to many faults. Below are a few steps which must be included in the PM programs:
- Visual checks
The greatest tool at your disposal. Visual inspection, if performed accurately, can detect or predict most of the faults. Take a long and careful look at all parts of motors and record your observations. Look for corrosion, burnt parts, dirt build-up or any other physical condition that might hinder its performance. Make sure to house the equipment in an environment free of dirt and moisture.
- Inspection of commutator and brush:
Commutator is a split ring device used to keep the direction of magnetic field constant. Nowadays, spring-loaded brushes are used as opposed to copper brushes used earlier. Hence, maintenance of these parts is of immense importance.
Since, they are a rotating part of the electric motor, frequent wear and tear of these parts is quite common. The brush needs to be changed, once it has worn out, to avoid any commutation problems. Similarly, one should look for dents and scratches on the commutator which might indicate brush sparking and must replace it.
- Winding Test:
The next step should be to perform a winding test. This would give you a deep insight into the existing problems. The test involves dissembling the electric motor part by part and looking for any signs of damage that might have been caused by overheating. Burn marks, cracks or any burning odor from the windings must not be ignored. The motor windings must be changed and tested to ensure smooth functioning.
Lubrication in the right amount is of utmost importance, as both greasing above and below the stipulated amount would damage the bearings. Under greasing could lead to wear and tear due to overheating and over greasing causes tolerance stack up, both reducing the life of bearings.
Bearings can be lubricated using either oil or grease, depending on the type of bearing used. When installing a new bearing assembly, you should check whether they are pre-greased and must not over grease. Some of the motors with low horse power do not need lubrication at all. Hence proper knowledge of the type of bearing used is a pre-requisite to its maintenance.
- Infrared thermology:
This is technique has become extremely popular due to its excellent results. An infrared camera is used for thermal imaging the motor without interfering with its operation. This provides information about the temperature and heat patterns of the motor over a specific period of time. In case of any faults, the camera will immediately detect an unstable voltage and produce an image which can then be used to identify the fault.
- Maintenance of records:
It is essential to maintain records every time you perform any of the above tests so as to establish a pattern/ trend. Doing so also creates a better understanding and helps in future inspections.
A strict preventive management regime must be followed for better outputs both in terms of produce and finance.