Siemens Spindle Motor Repair

Description – Siemens Spindle Motor Repair

Make – Siemens

Model – 1PA6133-4HF03-0BB3

This Siemens AC Spindle motor was sent to us for a repair after it started to trip on site with an earth fault. The motor was brought to our works and assessed in our spindle motor workshop. The spindle motor was stripped down and we found oil ingress in the windings and encoder. The stator was washed out and stoved, afterwards it was checked for integrity using resistance, megger, HI-POT and Baker surge testing methods.

The rotor and end-shields were cleaned and checked for size. Both bearing housings were oversize, these were bored out, sleeved and machined back to size. The rotor was balanced to G1.0. New bearings were supplied and the motor was built up. The encoder had suffered damage beyond repair so a new OEM unit was ordered. This was fitted and set to the motor. The special thing about these motors is the speed they operate at. A normal 50Hz supply is not a good test for these motors especially when the maximum operational speed is 8000rpm. A 50Hz supply will only run these motors to 1500rpm.

We have designed and built a High Frequency Spindle Drive Test Rig that tests these motors to their maximum operating speeds. This motor was run at 265Hz where the maximum operational speed of 8000rpm was reached. The bearings were checked at this speed and we ran the motor until bearing temperature plateau. Mechanical checks were carried out and we then tested the encoder was operating correctly by running the motor in closed loop mode.

Spindle Motor as we received it

Spindle Motor as we received it

Oil ingress in the motor windings

Oil ingress in the motor windings

Repaired and fully tested motor

Repaired and fully tested motor