TM 55-2210-224-34
3-64. TRACTION MOTOR ASSEMBLY (cont)
TEST (cont)
37. Perform a Bar-to-Bar resistance test by the following:
a. Place lead (1) of multimeter (2) on the shaft or core of the armature.
b. Place lead (3) of multimeter (2) on one of the commutator bars. Note and record indication on multimeter.
Contact each successive bar around the commutator and record each indication.
c. If the test shows resistance indication are 10 percent or more above the average recorded indication on 20 or
more connections, TIG weld all coil leads to commutator neck connections. Resistance indications of 1/2 percent
below the average or a full-scale meter deflection of the multimeter indicates a shorted coil to the armature.
WARNING
Heated parts may cause injury to personnel if hand protection is not worn when handling. Wear
protective gloves for maximum protection.
d.
Below-average readings could indicate the presence of water in the coils. If below-average readings are
obtained, bake armature in a convection oven for 4 hours at 230
°F (110°C).
e.
Cool at room temperature and repeat step b.
f.
If readings are still low, replace armature.
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