Alpha Technologies AlphaGen 5.0kW Auxiliary Power Unit - Manual (Page 33)

2. Turn-Up and Test
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031-132-B0-001 Rev. A TM ©2000
2.3 Generator System Sensor Verification, continued
2.3.2 AC and DC line Sense Verification
The ECM monitors AC line and DC bus status to determine when to start and
stop the APU. In the event of an extended power outage or low battery bus
voltage the ECM will start the APU. The following test will verify these
functions.
1. Verify the ECM is in the Auto position, the APU is not running, and there are
no major or minor alarms reported other than “Tamper”. Remove the DC
sense cable from the front of the ECM (see figure 1-5). Verify the APU
starts running and the ECM reports a minor “DC Bus Fault” alarm. Replace
the DC sense cable and verify the alarm clears.
NOTE: As the ECM will continue to run the APU for 30 minutes
after the “DC Bus Fault” alarm clears, the technican
may move the RAS switch to the STOP position after 4
to 5 minutes
2. Verify the RAS switch is in the Auto position, the APU has run for 1 minute.
Remove the AC Utility Line sense cable from the front of the ECM (see Fig.
1-5). Verify the ECM reports a “line Failure” notification and the APU starts
running after a 3 minute time delay. Replace the AC Utility Line sense cable
and Verify the notification clears. Verify the APU will continue to run for a 12
minute “cool down” period after the “Line Failure” notification clears.