PlantServices.com brings up an important aspect of motor repair – losing motor efficiency from having your motor repaired.
There are four types of losses — frictional losses, resistive rotor losses, iron losses and resistive stator losses. Stator and rotor winding losses are the most significant, followed by iron losses, with frictional losses accounting for less than 10 per cent of the total. These losses are the result of magnetic flux created as the motor is running. Under the old efficiency testing standard, additional load losses were estimated at 0.5% of the input power at rated load. This improvement is largely due to the absence of electrical and friction losses due to brushes. The enhanced efficiency is greatest in the no-load and low-load region of the motor’s performance curve.
To eliminate the core loss problem, repair shops should perform a core loss test before and after the repair to verify no increased losses. The tolerance must be within the core loss tester’s tolerance. Any variation should be reported to and agreed to by the machine’s owner. It’s important to understand, as well, that previous damage is difficult to mitigate and that increases in core losses by any practice following the first improper repair can be expected.
Electric motors are the single largest electric technology deployed in terms of energy use, which is why the DOE creates Minimum Efficiency Performance Standards (MEPS) in regulations like EISA. Electric motors convert an estimated 40 to 60 percent of all electricity generated in the world into mechanical energy.
Our services centers are thorough in their procedures when it comes to repairing, or rebuilding your motor, generator, or other rotating apparatus. We adhere to ISO specifications and are certified to 9000:2008. Does your repair center?