Instructional Booklet
Page
30
Effective: March 2021
Operation and Maintenance Manual,
Automatic Transfer Switch Controller, ATC-900
For more information visit: www.eaton.com
IB140012EN
6.3.1 Transfer Switch Appears Inoperative
Step 1:
Verify that all plugs and sockets are properly intercon-
nected.
Step 2:
If the source available LED is not on or the display shows
the wrong voltage, make sure the controller setpoints
match the system voltage. Verify that the correct system
voltage is at the switch.
Step 3:
Verify that the voltage selection plug on the transformer
is in the proper position to match the system voltage.
Step 4:
Look for any obviously burned components. Determine
the cause and rectify, if possible. Replace defective com-
ponents after the cause is determined.
Step 5:
Is switch closed on source 1? Verify whether or not the
system voltage now appears on the load terminals.
If YES: Proceed to check logic for problems in respective
logic instruction book.
If NO: Check all power connections and the switching
mechanism. What does the controller show for
voltages on the main screen?
6.3.2
Transfer Switch Will Not Automatically Transfer to Normal
Step 1:
Is Option 29G installed? If so, there is a switch on the
door Labeled Auto Manual with either push buttons for
S1 close, Trip, S2 Close or a three position switch with
the same. The Auto Manual selector-switch must be in
Auto for it to run with the controller.
Step 2:
Is Option 9B installed? If so, there is a selector switch
labeled “Maintenance”(or "Monitor Mode" for contactor-
based switches.
If YES: Verify selector switch is in the “Operate”
position.
If NO: Proceed to Step 3.
Step 3:
Are the correct line voltage and frequency available at ter-
minals N1, N2, and N3? Record the readings.
If YES: Proceed to Step 4.
If NO: Check Preferred source.
Step 4:
Is the transformer voltage selector plug in the correct
position?
If YES: Proceed to Step 5.
If NO: Position plug correctly.
Step 5:
Check the voltage on transformer NT1 by measuring volt-
age between voting relay KV-1 and GND. Is the voltage
measured 120 Vac (+/- 10 volts)? Record the reading.
If YES: Proceed to Step 6.
If NO: Check voltage transformer NT1.
Note:
For contactor Bypass type switches, the doors need to be closed and
latched for Normal Operation
Step 6:
Is the Preferred power source available?
If YES:Proceed to Step 8.
If NO: Apply the correct system voltage to Preferred
Source
connections. or change the setpoints on the
controller to match the system voltage
Step 7:
Is the switch connected to the Non-preferred source?
If YES:Proceed to Step 8.
If NO: Proceed to Step 9.
Step 8:
If a problem persists, contact Eaton.
6.3.3 Transfer Switch Will Not Automatically Transfer To the
Non-Preferred Source
Step 1:
If the alternate source is a generator, is it running?
If YES: Proceed to Step 2.
If NO: Check the generator. Check the engine start
contacts.
Step 2:
Is the correct line voltage and frequency available at the
Non-preferred source terminals? Record the readings.
If YES: Proceed to Step 3.
If NO: Verify that there is output voltage from the
generator.
Step 3:
Is the voltage selector plug in the correct position?
If YES: Proceed to Step 4.
If NO: Position plug correctly.
Step 4:
Is the Preferred source available?
If YES: Proceed to Step 5.
If NO: Proceed to Step 6.
Step 5:
Is a test Engine Test or Plant Exerciser being run, or is
the "Go to Emergency" input energized?
If YES: Proceed to step 6.
If NO: STOP! The transfer switch should not transfer to
the Non-preferred source if the preferred source is avail-
able and connected.
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