Hobart 60PL20 Operation And Maintenance Manual page 93

TROUBLE, SYMPTOM
AND CONDITION
LOAD CONTACTOR OPERATING CIRCUIT
1. Load contactor (K1)
will not close when
control switch (20,
Fig. 1) is held in
ON position. Gener-
ator running at
normal voltage. No
fault lights on.
December 31/91 Revised
PROBABLE CAUSE
A. In addition to de-
fective wiring and
connections in the AC
and DC load contactor
actuating circuits,
the load contactor
may be prevented from
closing for any one
of the following
reasons:
(1) Blown fuse (F1)
(1-1; 16, Fig. 8)
(2) Defective (open)
relay in protec-
tive module (1-1;
4, Fig. 8)
(3) Defective load
contactor control
switch (S5) (20,
Fig. 1)
(4) Defective recti-
fier (CR6) (1-1;
5, Fig. 11)
(5) Defective load
contactor coil
(K1) (1-1; 6,
Fig. 11)
TEST, CHECK, AND/OR
REMEDY
A. After checking fuse (F1) in
step (1) below, check all
wiring and connections in
the load contactor circuits.
Then check components as
follows:
(1) Remove and inspect fuse.
Replace if blown.
(2) Replace protective
module with a module
known to be operating
properly. If contactor still
doesn't close,proceed to step (3).
(3) Set Regulated/Diagnos-
tic switch (S1) in
REGULATED position.
Check AC voltage input
to contactor rectifier
(CR6). If voltage isn't
approximately 115-V AC,
contactor control
switch is defective and
must be replaced.
(4) After making certain
that contactor switch
(S5) is providing 115-V
AC to the rectifier
(CR6), measure DC out-
put voltage between
positive (+) and nega-
tive (-) terminals of
rectifier. If voltage
measured isn't approxi-
mately 90-V DC, replace rectifier.
(5) Disconnect leads at load
contactor terminals X1 and X2.
Check coil resistance between
these terminals. Resistance
should be approximately 600
ohms. If coil is defective, replace
the complete load contactor.
OM-2053
3-1
Page 15