Stator motor

we first tested the starter on a machine to test and see that the starter is actually functioning before we start dismantling it. The voltage on the starter motor was 11.9V and 58.9 amps. Next we disassembled the starter motor and performed a visual check of the components for any damage, burning physical damage to the coil and poling. The brush on the motor was worn alot. Next we tested the ground test by putting the red lead on the segments of the commutator and black on the armature shaft.The reading was infinity, which is good. Next we tested for the continuity on the armature by placing one probe on the segment and another on another segment. It read 0.2ohms which meets the specs.

Next was to test the diameter and the mica undercut of the commutator with a vernier caliper. My results were 27mm for the diameter and 0.6mm for the undercut. Both met the specs. After that we tested the armature with a 48volt test light, putting the two probes on the segment and it lighted up.

Next we performed a visual check on the field coils and pole shoes and they were all in good shape. Then we tested for continuity in the coils and the grounding. Both met the specifications as they both had 0 ohms when it was not grounded. Now we had to measure the brushes with the vernier caliper. The minimum length was 5mm and my results were 13.94, 16.4, 13.1, 12.8mm so, all were in good shape.

We then tested the solenoid magnetic switch to see the current draw on the component and to check it pulls in when power is supplied and it is held there for atleast 10 seconds. Before reassembling the starter motor, we did a visual check of the pinion gear,brushes and the clutch to check for wear. All were fine.

We reassembled the starter and checked it on the machine to make sure it is working. The no load readings were 11.8V and 46A. The starter is all good.