Motor Test - Graco A Series Instructions-Parts List Manual

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
1. Remove the drive housing. See page 28. This is to
ensure that any resistance you notice in the arma-
ture test is due to the motor and not to worn gears
in the drive housing.
2. Remove the junction box screws (56). Lower the
junction box. Disconnect the two leads (C) from
the motor to the board (47). See Fig. 15.
Armature Short Circuit Test
1. Remove the fan cover (B). See Fig. 14.
2. 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 replaced. See page 26.
Armature, Brushes, and Motor Wiring
Open Circuit Test (Continuity)
1. Connect the two black motor leads together with a
test lead. Turn the motor fan by hand at about two
revolutions per second.
2. When turning the fan on a DC motor, normally you
sense an even, pulsing resistance. If there is
irregular turning resistance, or no turning resis-
tance, remove the motor brush inspection covers
(A). See Fig. 14. Check and repair the following as
needed: broken brush springs, brush leads, motor
leads; loose brush terminal screws, motor lead
terminals; worn brushes. See page 20.
3. If there is still uneven or no turning resistance,
replace the motor. See page 26.

Motor Test

Fig. 14
RED
GREEN/
YELLOW
BLACK
BLACK/
WHITE
C
59
Fig. 15
A
MOTOR
WHITE
BLACK
47
10
B
54
03177