Replace vs. repair motor

Motor, AC motor, Motor repair

Individual organizations should consider developing their own customized Motor Management plan and policy. Some of the factors to consider are: extent of the repair - is it bearings or rewind, lead time for repair vs replace (special builds vs off the shelf), cost of new vs repair, single phase vs three phase, size (HP) of the product, efficiency of the failed motor vs efficiency of the replacement motor, warranty of the new vs repaired. Each organization's criteria and situation will factor into their individual decision tree.

Before you establish what %HP of the new motor value you will spend on repair, you need to know your repair facility. Your service center needs to be following the "EASA AR-100 Recommended Practices". Following these repair guidelines, you will not lose efficiency in the repair process, in fact on larger HP's, there maybe opportunities to gain efficiency if your EASA shop gets EASA engineering involved. Additionally, the repair center should have a recognized and accredited Quality Assurance Program, such as ISO 9000. Weighing in on your decision, compare the new motor to what you are going to get back. Typically a new Nema T frame motor will be insulation Class F (155' C), many EASA facilities will rewind with insulation Class H (180' C) and you will immediately have a 25' C advantage over new. Also, a qualified individual rewinding at an EASA repair facility is (highly) likely to produce greater quality than the factory cranking out "production". Balance standards are also typically better which will yield longer bearing life when the motor is back in service.

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It depends on the org or individual involved in the project.The guiding factor is the constraints which exist at the time.If constraint is cost,one should weigh the cost of rewinding, risks/benefits with a new one.Individuals/organizations risk acceptance level could be high/low.If high,rewinding can be embraced irrespective of the probable negative impact.If low, new motor could be best option.The part of the world you are also matters. If the cost of labour is high,the probability of rewinding will be low.If constraint is quality/time,then the benefits of rewinding has to be weighed objectively before a decision is made.One major factor is the size of the motor.For small motors,the tendency to rewind may vary from low to medium.But for high capacity motors,rewinding is first choice if a good company can do it.Replacement cost may be high and not in budget.Finally, org's/ individual's view of asset also matters. If the book value is low,replacement is the next option.In summary,it may or may not be a rule ,standard. It could just be individual's management decision.

<- - Comment made by: Chris Chin - ->

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