Idramat motor testing 1

[sprout000]

Does anyone have the correct setup and testing procedure for MKE047B indramat motors speed feed back units.The motor involved has been reassembled after a mechanical repair.It drives for a short period of time(backwards)then faults with a velocity feedback error?

 

[rawelk]

This could happen if motor power phasing is wrong. Verify it is correct (check the drive controller documentation).

I haven't used the MKE047B motor, but Indramat motors that I have store various information about the motor, including the commutation offset angle, in memory storage built into the encoder. When the drive amplifier powers up it checks whether the motor has changed by querying encoder memory, and, if it has, "marries" the motor/encoder to the amp.

I'm not sure of the details, but, when a qualified Indramat motor shop repairs one of their motors they'll need to use a special software program to communicate with the encoder, and set it's commutation angle offset. They need to associate the encoder's 0° position to the motor's 0° angle.

One way to do this is drive a DC current through two of the motor phase coils (which will rotate it to a fixed point, and hold it there - we'll call this 0° motor shaft position), then adjust the encoder's commutation offset value until encoder feedback represents a 0° angle.

If physical orientation between the encoder to motor shaft changed during your repair then the commutation angle will almost certainly be wrong.

The bottom line is the drive amplifier will no longer know where the rotor shaft is in relation to the windings, won't be able to switch on it's output transistors correctly, and all manner of odd operation (running backwards, throwing velocity error faults, pulling abnormally high current, etc.) will result.