Pic. 7.23. Checking resistance between slip rings
Use an ohmmeter to measure the resistance between the slip rings (pic. 7.23).
Rated resistance (V «cold» able): 2.7-3.1 ohm.
If the resistance tends to infinity, i.e. circuit is open, replace the rotor.
Pic. 7.24. Checking the circuit of the field winding on «mass»
Check if there is a short circuit in the field winding «mass» (pic. 7.24).
Using an ohmmeter, measure the resistance between the rotor pole and the slip ring.
If resistance is 0 (circuit is closed), then replace the rotor.