Starting/Charging Systems (H6DO): Starter: Inspection: Armature: Notes

Check the commutator for any sign of burns of rough surfaces or stepped wear. If it has minor wear, correct it by using sand paper (#300).
Run-out test
Check the commutator for run-out, and then replace if it exceeds the limit.

Commutator run-out:

Standard

3.1 mm (0.1220 in)

Service limit

Less than 3.8 mm (0.1496 in)

Fig 1: Checking Commutator For Run-Out
Courtesy of SUBARU OF AMERICA, INC.
Armature short-circuit test
Check the armature for short circuit by placing it on growler tester. Hold an iron sheet (thickness gauge, etc.) against the armature core while slowly rotating the armature. A short-circuited armature will cause the iron sheet to vibrate and to be attracted to core. If the iron sheet is attracted or vibrates, the armature, which is short-circuited, must be replaced or repaired.

Fig 2: Identifying Armature Short-Circuit Test
Courtesy of SUBARU OF AMERICA, INC.
Armature discontinuity test
Using a circuit tester, touch one probe to the Armature and the other to commutator. No continuity is normal. If there is continuity, the armature is grounded.

Replace the armature if it is grounded.

Fig 3: Identifying Armature, Commutator And Circuit Tester

Courtesy of SUBARU OF AMERICA, INC.