Hobart JET-EX 4 Operation And Maintenance Manual page 80

OM-2049
TROUBLESYMPTOM
AND CONDITION
GENERATOR AND CONTROLS
1. Generator will
not build up
voltage at all
when push-to-
build-up volt-
age switch
(S407) is
operated.
Engine running
normally.
(Cont'd)
2. Generator builds
up to only a low
voltage while
push-to-build-
up voltage
switch is
depressed.
3-1
Page 18
PROBABLE CAUSE
C. Generator revolving
field (L406) defective.
D. Defective generator
armature (G402)
A. Generator voltage
regulator fuse (F403)
blown.
B. Defective control
winding rectifier
C. Generator voltage
regulator (VR402)
defective.
TEST, CHECK, AND/OR
REMEDY
C. Locate yellow and red-orange
wires on terminal strip that is
just beneath base of voltage
sensing relay (at rear of
control panel). Disconnect the
yellow and red-orange wires
which go down to the generator.
(Refer to connection diagram
488860 in Chapter 5). Measure
resistance between these two
wires. Should be 6 to 8 ohms.
If reading indicates an open,
short or lower than normal
resistance, proceed to Step D.
D. If check of the generator
revolving field (Step C above)
revealed no trouble, the gen-
erator armature is defective.
Send unit to overhaul.
A. Replace voltage regulator
fuse (4, Fig. 3). Resume
operation of generator set to
see if problem is corrected.
If not, proceed to Step B.
B. Check control winding rec-
tifiers (3, Fig. 3) with an
ohmmeter to see if they are
good. If either rectifier
is defective, replace it. If
both rectifiers are good,
proceed to Step C.
C. Replace voltage regulator
(1, Fig. 3).
May 20/89