Service Manual — COATS Models 950/950 ProRacer/1025/1050/1055 • 15
Does the Balancer trip a circuit
breaker on the electrical panel
when it starts the brake cycle?
CONTINUED FROM
LAST PAGE
Manually close the brake
contactor. Is there 220VDC on
between terminals 13 & 54 on
the forward contactor?
Manually close the brake
contactor. Is there 220VAC
between terminals 3 & 5 on
the lower contactor?
Check the bridge rectifiers.
See Checking Procedure.
Turn the power switch OFF and unplug
the balancer from the power source.
Manually close the brake contactor. Use
an Ohmmeter to check between termi-
nals 53 & 54 and between terminals 83
and 84 on the brake contactor. Is there
less than 1 Ohm on both checks?
Replace the auxiliary
brake contactor. See
Replacement Procedure.
Turn the power switch OFF. Manually close the brake contac-
tor. Use an Ohmmeter to check these connections for conti-
nuity on the brake contactor, 63 to 64 & 73 to 74. If your meter
fails to read 0.0 ohms, replace the auxiliary (piggy back)
contactor on the brake contactor. While the contactor is closed
also check terminals 1 to 2 on the brake contactor. If your meter
fails to register any resistance, replace the primary contactor.
Use an Ohmmeter to check the following connections. If your
meter fails to register 0.0 ohms, repair or replace the defective
wire or connection(s) associated with the terminals just checked.
Forward contactor terminal 1 to brake contactor terminal 2.
Forward contactor terminal 5 to brake contactor terminal 1.
Forward contactor terminal 3 to brake contactor terminal 63.
Forward contactor terminal 73 to brake contactor terminal 64.
Forward contactor terminal 53 to brake contactor terminal 74.
Forward contactor terminal 83 to brake contactor terminal 73.
Yes
No
Yes
No
No
Yes
No
Yes
Replace the contactor. See
Replace Procedure.
After verifying the integrity of
the motor connections to the
contactor, replace the motor
assembly. See Replacement
Procedure.
Use an Ohmmeter to check for continuity on the following
connections. If your meter fails to register any resistance,
repair or replace the defective wire or connection(s) associ-
ated with the terminals just checked.
Forward contactor terminal 13 to brake contactor terminal 84.
Forward contactor terminal 54 to brake contactor terminal 54.
Brake contactor terminal 83 to both rectifiers terminal “+”.
Brake contactor terminal 53 to both rectifiers terminal “-”.
Brake contactor terminal 5 to all 4 rectifier terminals “~”.
(Only one terminal on each contactor will give a reading.)
Brake contactor terminal 13 to 2 rectifier terminals “~” that did
not render a reading in the previous check.
Direct Drive
Manually closing the contactor to check voltage
may cause the wheel to spin at high speeds. To
avoid this from happening disconnect the wires
going from the contactor to the motor.
CAUTION
