Inside a repaired electric motor there are many original components as well as those that have been replaced or repaired and not only is the quality of those being replaced important, so too is the handling and processing of the original components otherwise you might be getting back a bomb. You can’t judge by looking at the outside of a machine as to how it has been processed or handled so the culture and expertise of the repair company is paramount if any confidence is to be had in the quality of the returned asset. If you could see and judge all the components involved after a repair has been carried out, what would be their sum value and will it cost you more power to operate this machine in the future?
The core of the problem is often just that, the laminated core that is, as it is this component which is particularly vulnerable because it relies on a thin layer of insulation (between individual laminations) to minimize the circulating currents that would otherwise flow when the machine is in operation. If this insulation is damaged during the repair process then higher operating temperatures and running costs due to loss of efficiency will result. It is by the use of appropriate equipment and techniques that risk of damage to these components is minimized, but unfortunately due to cost cutting and often ignorance these are not always available. You will not physically see this type of damage, though it will certainly manifest itself as described above as well as reducing the life expectancy so this poses some important questions for clients when considering repairs!
Does the supplier have a culture of quality? Do they have qualified and quantifiable expertise, appropriate equipment and facilities, levels of supervision and commitment to training? Are they working to a quality management program and are they audited and certified? Do they belong to an industry association relevant to the activities they carry out? Are they insured?
There are many good and competent service organizations presently operating so it is simply a matter of investigation and questioning; what are you really paying for?