Hobart 120CU20, Operation And Maintenance Manual With Illustrated Parts List

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OM-2228 / Operation and Maintenance Manual
120CU20 / Series 500120 / 400 Hz. Generator Set
October 15, 2013 Chapter 2-3
Page 6
(5) Place the No. 1 EF bypass switch to “ BYPASS / OFF ” position. The No. 1 load contactor should
open at once and the yellow indicating light within the No. 1 load contactor push button switch
should go off and the fault code display should also read “
EF 1 ”, indicating a EF warning. The
corresponding LED should also indicate the EF present mode. Reset the fault by pressing the
“
TEST/RESET ” push button.
(6) Proceed to step 12.
(Steps 7 - 11 are only required if EF interlock system is not available on a load bank.)
(7) Connect a source of 24 VDC power (two twelve-volt batteries connected in series) to terminals N,
F (or E) at the output terminal panel. Connection polarity is important. Connect plus (+) to
terminals E or F, and minus (-) to terminal N.
(8) Verify that when the EF Bypass switch is in the “ BYPASS / ON ” position or the “ BYPASS / OFF ”
position, that the appropriate LED indication on the control panel display (Figure 5) is correct
during the following steps 9 and 10.
(9) Place the No. 1 EF bypass switch to “ BYPASS / OFF ” position. Press the No. 1 Output
pushbutton switch. The No. 1 Output indicating light, within the push button switch, should glow
and remain on when the push button switch is released. This indicates that the load contactor is
closed and the plug interlock circuit is functioning properly.
(10) Disconnect the 24-VDC power source and the No. 1 load contactor should open immediately, and
the indicating light within the push button switch should go OFF. The fault code display should
also read “
EF 1 ”, indicating an EF warning. This is because the interlock circuit of the control PC
board is not receiving 28.5 VDC signal from an outside source. It indicates that the No. 1
interlock circuit is OPEN, as it should be when the interlock circuit is not receiving a 28 VDC
signal. Reset the fault by pressing the “
TEST/RESET ” push button.
Figure 4: EF Bypass Indication.
EF Bypass Indication