3-16. Before connecting the power cable to the aircraft, start the APU. With the
APU at operating speed, move the ac power CLOSE-TRIP switch to the center posi-
tion. Check the voltages on all three phases using the ac selector switch.
3-17. Connect the power cable to the aircraft receptacle, and move the ac power
CLOSE-TRIP switch to CLOSE. CB CLOSED lamp will illuminate. An AC FRE-
QUENCY meter is provided on the instrument panel. AC volts and amperes may be
read on the AC VOLTS and AC AMPERES meters provided on the instrument panel by
selecting the phase desired with the AC selector switch.
if an overvoltage condition exists. The CB CLOSED lamp will extinguish. An engine
malfunction shutdown will also cause the ac generator to go off the line.
3-19. Move the AC power CLOSE-TRIP switch to TRIP before stopping the APU after
an ac power utilization run. The CB CLOSED lamp will extinguish.
3-20. APU STOPPING.
Move AC power CLOSE-TRIP switch to TRIP.
a.
Pull VOLTAGE REG circuit breaker.
b.
c.
Move START-RUN-OFF switch to OFF.
Move BOOST PUMP switch to OFF.
d.
3-21. APU REMOVAL.
3-22. Removal of the APU from the mobile check stand is the reverse of the installa-
tion procedures given in paragraph 3-4. Perform the following steps after removal of
the APU from the check stand.
Disconnect the battery.
a.
Reinstall the metal cover on the rear pad of the speed increaser.
Secure the
b.
cover to prevent the loss of the spline drive adapter.
c.
Remove the tachometer generator from the APU speed switch, and stow in
receiver inside the control console door. Place the nuts, washers, and drive
coupling adapter in a cloth bag and stow with the tachometer generator for
future use.
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