Inspection and Repair

Repair or replace necessary parts if extreme wear or damage is found during inspection.

Armature




Check for continuity between commutator and segment. Replace commutator if there is no continuity (i. e. , disconnected).




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 (i. e. , internally grounded).

Brush
Measure the length of brush.
Replace with a new one, it it is below the limit.




Brush Holder
Check for continuity between brush holder (+) (4) and base (-). Replace, if there is continuity (i. e. , insulation is broken).




Magnetic Switch
Check for continuity of shunt coil between terminals S and M.
Replace, if there is no continuity (i. e. , coil is disconnected).




Continuity of Series Coil
Check for continuity between terminals S and M.
Replace, if there is no continuity (i. e. , coil is disconnected).




Continuity of Contacts
With the plunger faced downward, push down the magnetic switch. In this state, check for continuity between terminals B and M. Replace, if there is no continuity (i. e. , contacts are faulty).




Pinion
Check if the pinion rotates smoothly in drive direction by hand, or if it is locked when it is rotated in reverse. If not, replace the pinion.