Motor Brush Inspection; Electro-Mechanical Parking Brake Testing - Invacare Ranger II Basic Service Manual

PROCEDURE 2

MOTOR BRUSH INSPECTION

(FIGURE 4)
T
There are two (2) contact brushes on the motors located
R
under the brush caps on the motor housing. If these caps
O
are hard to remove they are either overtightened or the
U
motor has become very hot. Let motors cool. If caps still
B
cannot be removed, it is recommended that the motor be
L
sent to Invacare Technical Services for inspection/repair.
E
S
NOTE: It is very important to note which way the brush
H
comes out of the motor. The brush MUST be placed into
O
the motor exactly the same way to ensure good contact
O
with the commutator.
T
I
1. Once the motor brush caps have been removed, pull
N
the brushes out of the motor. The end of the brushes
G
should be smooth and shiny and the spring should
not be damaged or discolored. If one or both of the
brushes are damaged, only the damaged or worn
brushes need be replaced. It is very important that
any time a brush is replaced, it must be "burned in".
This is accomplished by running the motor for one
hour in each direction with a half hour break in-be-
tween. This should also be done with little or no load
on the motor, i.e., put the wheelchair up on blocks so
the drive (large) wheels do not contact the ground
and run the wheelchair. A motor with only one brush
replaced will only carry a small percentage of its rated
load capacity until the NEW brush is burned in.
Cap
4 Pin Motor Connector
FIGURE 4 - MOTOR BRUSH INSPECTION
ELECTRO-MECHANICAL PARKING
BRAKE TESTING (FIGURE 5)
1. On the four-pin motor connector, locate the side by
2. Set the digital multimeter to read ohms (Ω).
3. Measure the resistance between the two (2) brake
NOTE: A bad motor can damage the controller module
but a bad controller should NOT damage a motor.
Motor
14
side connectors in the black housings.
contacts. A normal reading is 100 ohms (Ω). A read-
ing of 0 ohms (Ω) or a very high reading; i.e., MEG
ohms or O.L. (out of limit) indicates a shorted brake
or an open connection respectively. If either condition
exists, send the motor to Invacare Technical Service
for inspection/repair.
CAUTION
A shorted electro-mechanical brake will
damage the brake output section in the con-
troller. DO NOT connect a shorted electro-
mechanical brake to a good controller mod-
ule. A shorted brake MUST be replaced.
Cap
4 Pin Motor Connector
FIGURE 5 - ELECTRO-MECHANICAL
PARKING BRAKE TESTING
TROUBLESHOOTING
Motor
Ohmmeter