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 5
c) Testing the No. 1 Output Circuit.
(1) Place the EF Bypass switch in “ BYPASS / OFF ” position and turn the EF signal “ ON ” on the load
bank. Then press the yellow No. 1 load contactor push button switch to close contactor, which is
indicated when its internal indicating light glows.
(2) Place the EF switch on the load bank in the “ OFF ” position. 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 3: Digital Control PC Board.
(3) 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 4) is correct.
(4) Place EF bypass switch (Figure 4) in “ BYPASS / ON ” position. Press the No. 1 load contactor
push button switch. The No. 1 contactor power indicating light within the push button switch
should glow and remain on when the push button switch is released. This indicates that EF
bypass switch is functioning correctly. The corresponding LED should also indicate the bypass
mode.