Has anyone been successful testing high speed spindle motors (10,000 rpm) with motor circuit analysis? We have a PDMA EMAX tester.

I've tested many high speed motors for grinding applications & found faults correctly in them. I use an All-Test IV. Typically found variations in the I/F values across the phases.

Regards,

Aditya

Aditya and Kapt

The reason for the variations in test results has to do with the magnetic rotor in most servo motors. With the ALL-TEST IV PRO, you have to either trend the difference in I/F or Fi, which will remain constant regardless of rotor position. The Impedance and inductive pattern comparison is still accurate for detecting winding contamination, even though the phase to phase unbalance will be significant.

When troubleshooting, you have to either perform a rotor test or adjust for rotor position. If you are unable to accurately position the servo motor, then moving the servo motor into a second position and re-testing. The unbalance should move from one phase to another, if it remains constant in one phase, then there is a winding problem.

Note: this will happen in only a few types of servo motors.

The power of low voltage testing such as the ALL-TEST Pro or PdMA, is that the low voltage, higher frequency tests do not have a negative impact on the windings or magnetic rotor. However, higher voltage testing will have the undesired effect of re-aligning the domains of the rotor, causing a cogging problem.

Howard