Motor Test
WARNING
INJECTION HAZARD
To reduce the risk of serious injury, whenever you are instructed to relieve pressure, follow the Pressure Relief
Procedure on page 9.
For checking armature, motor winding and brush electrical continuity.
Setup
Remove the drive housing. See page 24. This is to ensure that any resistance you notice in the armature test is due to the motor and not to worn gears in the drive housing.
Remove the motor brush inspection covers (A). See Fig. 12.
Remove the junction box screws (56). Lower the junction box. Disconnect the two leads (C) from the motor to the board (47). See Fig. 13.
Armature Short Circuit Test
Remove the fan cover (B). See Fig. 12.
Spin the motor fan by hand. If there are no shorts, the motor will coast two or three revolutions before coming to a complete stop. If the motor does not spin freely, the armature is shorted and the motor must be re- placed. See page 22.
Armature, Brushes, and Motor Wiring Open Circuit Test (Continuity)
Connect the two black motor leads together with a test lead. Turn the motor fan by hand at about two revolu- tions per second.
When turning the fan on a DC motor, normally you sense an even, pulsing resistance. If there is irregular turning resistance, or no turning resistance, check and repair the following as needed: broken brush springs, brush leads, motor leads; loose brush terminal screws or motor lead terminals; worn brushes. See page 19.
If there is still uneven or no turning resistance, replace the motor. See page 22.
B
A
06975
Model 231580 shown
Fig. 12
MOTOR
|
| 89 |
| BLACK/ |
|
| WHITE |
|
| BLACK |
|
59 | C |
|
|
| |
58 | RED | |
| ||
|
| 56 |
|
| 47 |
Fig. 13 | 04720 | |
| ||
3875 7