Hobart 6921 Series Operation And Maintenance Manual page 113

OM-2040 / Operation and Maintenance Manual
90D20 / Generator Sets
Generator and Excitation Circuit (cont.)
Trouble, Symptom & Condition
Load contactor (K1) will close
when control switch (20, Fig. 1
is held in momentary CLOSE
position. Opens immediately
when switch is released to
center ON position. (cont.)
5. Load contactor opens during
power delivery. NO fault
indicating lights on.
February 28/94 Revised
Test or Inspection
d. "Blown" fuse (F2) (1-1; 17,
Fig. 9) in protective relay
tray.
e. Defective plug-interlock
relay (K2).
f. Small contacts in load
contactor (K1) defective.
g. Defective fuse interlock
relay (K 17) or resistor
(R46).
a. Fuse (F1 or F2) blown.
b. A fault has developed in the
load contactor holding
circuit.
c. Cable accidentally
disconnected from aircraft.
Corrective Action
Press lamp test switch (8, Fig.
1). If lamps do not glow, replace
fuse (F2).
Place test-bank switch (S2) (34,
Fig. 1) in ON position. If load
contactor will now remain
closed, replace the
plug-interlock relay (K2) (Sect.
1-1; 1, Fig. 9) or the complete
protective relay tray.
Connect a jumper lead between
small terminals N.O. and C on
the load contactor. If the load
contactor will now remain
closed, replace the complete
load contactor (K1).
Open protective relay tray and
connect a jumper across the
resistor (R46) (Sect. 1-1; 21
Fig. 9). If the contactor will now
remain closed, replace fuse
interlock relay (K17) (Sect. 1-1;
2, Fig 9) or replace the
protective relay tray assembly.
Remove and inspect fuses (1-1;
16 and 17, Fig. 9.) Replace as
required.
If the load contactor cannot be
closed by operation of the
control switch (S5) (20, Fig. 1),
check the circuit in accordance
with instructions in Trouble 1,
above under LOAD
CONTACTOR OPERATING
CIRCUIT. If the load contactor
can be closed but opens as
soon as control switch (S5) is
released, check for trouble
under Trouble 2, above.
Reconnect cable.
Chapter 3-1
Page 21