It may not happen often but electric motor failure can have serious consequences when it does occur. In fact, it can be difficult to know just what to do. As business downtime and losses mount, it’s very easy to make a panicked decision over whether to rewind and repair or replace your motor.
What should motor owners do? With new high-efficiency motors available, do they take the plunge and invest in a whole new motor altogether that promises higher efficiency levels but with significantly greater costs? Or, do they commit to an electric motor rewind or repair? While the cost is often lower, many are concerned about the potential inefficiencies that an electric motor rewind can bring — yet are these worries grounded in fiction?
This way of thinking has been commonly attributed to a small number of studies surrounding smaller motors. It is claimed that carrying out a rewind can drop efficiency by between 1% and 5% each time it is rewound. Considering the associated expense and sheer volume of energy these motors use, this is naturally concerning. However, more recent research has countered these findings.
Involving 22 new motors ranging from 50 to 300 hp, EASA and AEMT conducted a study with Nottingham University. Overall, the results found that when electric motors were rewound using good practice, there was no significant change in the efficiency of the motors. However, in some instances, efficiency actually increased. This clearly dispels the belief that a rewind is actually detrimental to a motor’s performance.
Areas of consideration
This suggests that purchasing an expensive electric motor may not be required. Of course, in cases of catastrophic failure, this may be your only option. However, it’s very important to fully evaluate your options to make sure you make the right choice in terms of operation, cost and efficiency. This can be done by asking a number of key questions, as explained by Houghton International.
Is your electric motor still suitable for its original purpose?
It is possible that your electric motor may no longer be suited to your operational needs. Review the scale of the damage alongside the requirements for the motor’s processes and duty cycles. If the motor is no longer suitable or too damaged, your option is to replace the motor.
Are the stator core and rotor in a good condition?
It’s important to check the stator core and rotor of your motor. If significant damage is present, it may be more beneficial to purchase a new motor, as depending on the extent of the damage, repairs can be costly.
If you are considering making the investment, fully weigh up your options. For example, if the lead times for the motor you need are long, you may to decide to repair rather than replace to minimise downtime.
Has any damage occurred to other mechanical parts?
A result of motor failure, damage may occur to the shaft, frame, bearing housing, and other mechanical parts. Examine the extent of the damage; you may be able to replace the affected parts at a lower cost than replacing the entire motor.
Is it an EPAct or Nema Premium motor?
If your motor has failed, it could be the opportunity you have been looking for to upgrade to a more efficient model. If you are considering making the investment, make sure you fully understand the return you’ll receive from doing so. Consider the energy savings you’ll make alongside the expected life of the motor and its hours of operation. Always consider your overall budget too, to make sure the replacement aligns with your current financial position.
Remember that if you are happy with the existing efficiency of your motor, a repair by a qualified service centre may be all you need. It will not lead to a dramatic drop in efficiency, as we have discussed.
Consider the above in-depth to ensure you make the right choice in the event of motor failure occurring.