Blower Motor Assembly

6-4. Blower Motor Assembly

stator winding is defective. Follow the instruc-

a. On-Equipment Testing. Prior to removing

tions in c following and disassemble the motor

the blower motor assembly, test for open wind-

for further testing.

ings or shorts as follows:

b. Removal. Refer to paragraph 322 and re-

(1) Disconnect the receptacle connector from

move the blower motor assembly.

the control box. Test for continuity across each

c. Disassembly. Refer to figure 65 and disas-

combination of two motor terminals. Lack of con-

semble the blower motor assembly as required.

tinuity indicates an open winding.

d. Testing Procedure.

(2) Place one contact of tester against motor

(1) Overload protector. Disconnect the

housing and the other on one of the terminals,

electrical leads from the overload protector. Test

continuity will indicate a grounded motor.

the protector with a multimeter set on the ohm

(3) Test the motor stator for insulation re-

scale. If continuity does not exist, replace the ov-

sistance as instructed in TM 5764. The insulation

erload protector.

resistance should measure not less than 0.5 meg-

(2) Motor bench test. Perform the growler

ohms.

tests on the stator as instructed in TM 5-764. Re-

place defective stator.

Note. The resistance measurement should be used

e. Cleaning, Inspection, and Repair.

only as a guide, taking into consideration the accuracy of

the instrument used, test lead resistance, and ambient

(1) Clean all parts with a cloth dampened in

temperature at time of test. If more precise measurement

an approved solvent,

is required, an instrument such as a Kevin or Wheatstone

(2) Inspect the stator housing for cracks,

bridge should be used, or comparative measurements be-

breaks, or defects.

tween the suspected component and a like item known to

(3) Inspect bearings for pits, scoring, wear,

be in good condition. In all cases where a megometer is

used for testing, make certain that the unit is thoroughly

or out-of-round condition.

dry. Wet condemnation tolerances should be considered.

(4) Inspect the rotor shaft for cracks, wear,

misalinement, gouges, pits, or other damage.

(4) Connect the motor leads to a proper

(5) Inspect the rotor for cracks, breaks, and

source of power. Use a hook type ammeter and

damaged laminations.

read the amperage flowing in each of the motor

(6) Inspect all threaded parts for damage.

leads. On model 4V20 the ammeter should read

(7) Replace any damaged or worn part.

between 1.45 and 2.2 amperes at no load. On

f. Reassembly. Reassemble the motor assembly

model 6V20 the ammeter should read between

by reversing the order of disassembly.

1.75 and 2.5 amperes at no load. Start the unit

g. Installation. Refer to paragraph 322 and

and check the ammeter reading. If the readings

install the motor assembly.

are not equal, the motor bearings are worn or the

6-7