ASSEMBLY - TM-10-3930-607-150100

ELECTRICAL

frame, connect one of the ohmmeter leads to the

CAUTION: Do not use 110-volt test lamps to check

end frame, and the other ohmmeter lead to the

diodes.

diode lead and note the reading. (Fig. 14) Then

reverse the ohmmeter lead connections, and note

F. ASSEMBLY

the reading. If both readings are very low, or if

both readings are very high, the diode is

1. If diodes have been removed, press new ones

defective. A good diode will give one low reading

into place, using a tool which fits over the outer edge of

and one high reading. Check the other two diodes

the diode. Support the frame end and heat sink at the

in the end frame in the same manner.

same time.

CAUTION: Do not tap the diode into place, as the

shock may damage it and the other diodes.

2. If removed during disassembly, replace by

pressing the bearing into the drive end frame, using a

collar that just fits over the bearing outer race. Attach

the retainer plate.

3. Secure the rotor in a soft-jawed vise with the

drive end up. Tighten the vise only enough to permit

tightening the shaft nut to the correct torque.

CAUTION: Excessive pressure will distort the rotor.

4. Slide the drive end assembly over the rotor shaft.

5. Install the collar, fan and pulley. Secure the

assembly with the nut tightened to 50-60 pounds-feet.

Remove the assembly from the vise.

6. To install a new slip ring end bearing, place a flat

plate over the bearing and press in from the outside

towards the inside of the frame until the bearing is flush

with the outside of the end frame. Support the inside of

the frame with a hollow cylinder to prevent breakage of

Figure 14.

the end frame. Use extreme care to avoid misalignment

or otherwise placing undue stress on the bearing.

c. An alternate method of checking the diodes is

to use a test lamp of not more than 12 volts in

7. Saturate the felt seal with SAE 20 oil, and then

place of the ohmmeter.

With the stator

install the felt seal and steel retainer.

disconnected, connect the test lamp leads across

each diode as described in item b. first in one

direction and then in the other. If the lamp lights

in both checks, or fails to light in both checks, the

diode is defective. When checking a good diode,

the lamp will light in only one of the two checks.

B-63