Bench Testing: Armature

Measure the outer diameter of commutator, and replace with a new one if it is out of limit. See Fig 1. SeeSTARTER SPECIFICATIONS .
Check for continuity between segment and segment on the commutator. Replace commutator if there is no continuity. See Fig 2.
Check for continuity between commutator and shaft. Also, check for continuity between commutator and armature core, armature core and shaft. Replace commutator if there is continuity. See Fig 3. See STARTER SPECIFICATIONS .
Measure runout of the commutator with a dial gauge. SeeFig 4. Repair or replace, if it exceeds the limit. See STARTER SPECIFICATIONS .
Polish commutator surface with sandpaper #500 to #600 if it is rough. See Fig 5.
Measure the depth of insulator in commutator. Replace, if it is below the limit. See Fig 6. See STARTER SPECIFICATIONS .

Fig 1: Measuring Outer Diameter Of Commutator

Courtesy of ISUZU MOTOR CO.

Fig 2: Checking Continuity Between Segment & Commutator

Courtesy of ISUZU MOTOR CO.

Fig 3: Checking Continuity Between Commutator & Shaft

Courtesy of ISUZU MOTOR CO.

Fig 4: Checking Runout Of Commutator With Dial Gauge

Courtesy of ISUZU MOTOR CO.

Fig 5: Using Sandpaper To Polish Commutator Surface

Courtesy of ISUZU MOTOR CO.

Fig 6: Measuring Depth Of Insulator In Commutator

Courtesy of ISUZU MOTOR CO.