Industry News Display
2016-10-25 Plant Engineering
Assessing the motor before repairs and a well thought-out preventive maintenance program can help reduce efficiency loss and keep operations running smoothly.
By: David Manney, L&S Electric
In many businesses, electric motors are representative of a substantial capital investment. They also result in some of the highest costs for the ongoing operation of the business. At times, the company may end up paying ten times as much in energy as they do for the initial cost of the motor. The motor's efficiency is a key aspect during the repair process and should be a major consideration.
Having a well thought out preventive maintenance program at the facility is one way to contribute to reducing problems with electric motors. Like any piece of equipment, however, motors will eventually break down, and repairs will need to be made. A motor rewind is common electrical motor repairs and can provide many benefits for users.
It is commonly believed that rewinds cause a motor to lose efficiency, but that is an outdated understanding. When the proper materials and methods are used for rewinding, it will not have a significant impact on the reliability or the efficiency of the motor. In fact, it might improve both the power and the reliability associated with an electric motor when the rewind is performed by a trained and qualified service provider.
The need to assess the motor
Before any repairs take place, the motor needs to be fully accessed to ensure best practices are being followed. This is also where choosing the proper service provider is going to make a difference. When they fix the motor, they can make the appropriate inspection of it before the rewind takes place. This includes recording any data from the nameplate and documenting the procedure that will be used.
There are also factors to consider before the motor is disassembled. These will help ensure that the repair will not affect the efficiency or operation of the motor in a negative way. Some of the components of the motor that will be inspected visually include:
- Bearing cap and end bracket
- Shaft rotation
- Bearing type, size, and clearance
- Checks for contamination
- Signs of bearing wear
- Signs of heat damage.
It will also be determined if the motor winding is at the original factory setting or if it has been rewound at some time in the past. Careful measurements will be taken so the winding can be replicated accurately.
There are opportunities to improve motor efficiency during motor rewinds. Numerous factors such as putting more copper into the stator slots or increasing the wire diameter can be considered.
There may also be times when it is a better decision to replace the motor rather than do a motor rewind. This may be the case if there is damage to the motor core. The decision on whether to rewind the motor or replace it can be determined by the service provider and then the appropriate action can be taken.