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11.4 Blower
The motor blower is located to the right of the motor, and inside the motor
housing. It cools the motor during operation.
To verify power to the blower use the following procedure. It requires
operation of the unit with power applied and the front control panel removed.
Use caution to avoid electric shock (see Section 7.1, Cautions).
Remove the front control panel (see Section 8.1) and locate J4 (labeled
REFR/FAN on the board). At J4 use a voltmeter to measure the voltage
across pins 3 and 4 (both orange or black). Insert probes from the back of
the connector shell. The blower is active while the motor is running or
stopping. With a rotor properly installed, select an appropriate speed and
start the unit. Once the motor is turning, verify that the blower power should
be present by checking the FAN LED. If the LED is lit, approximately 120
Volts AC should be present. If voltage is present and the blower does not
operate, check the harness. If the harness is good, replace the blower. If
the voltage is not present when the LED is lit, replace the board.
Replacement of the blower is made easier if the unit can be placed between
two tables. This allows easy access to the bottom of the unit. The blower is
held in place by 4 screws. Remove the 4 screws and fan shroud from below.
Remove the drive assembly (see section 11.1). Slide the blower over and
remove it up through the guard bowl.
11.5 Brake
The Centra GP8 and GP8R feature six deceleration modes, max. brake (5
LEDs) through min. brake (1 LED), and coast (no brake, no LEDs).
The brake requires service if, with a fully loaded rotor and operating at that
rotor’s maximum allowable speed, the deceleration time in the brake mode is
not less than the deceleration time in coast (no brake).
The brake resistor is mounted to the base of the unit, and is surrounded by a
heat sink. The value of the resistor is 10 ý. The resistor is in the motor
circuit, so if the motor or brake do not work, check the resistor. To measure
the resistance, locate and disconnect J2 from the board. Measure across
pins 5 an 6 (both violet). Both leads should read open when measured to
ground.
Centra-GP8/GP8R Service Manual
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