3-62. TRACTION MOTOR ASSEMBLY (cont)
43. 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. Record reading on multimeter. Contact each
successive bar around the commutator and record each reading.
c. If the test indicates resistance readings of 10 percent or more above the average recorded readings on 20 or
more connections, tig weld all coil leads to commutator neck convections. If test indicates resistance readings of
1/2 percent below the average or a full-scale meter deflection of the multimeter, there is a shorted coil to the
Procedures specify the heating and cooling of parts to aid in disassembly and assembly. Heated and
cooled 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° (110°C).
e. Cool at room temperature and repeat step (b).
f. If readings are still low, replace armature.