Hobart Jet-Ex 5D Operation And Maintenance Manual page 65

OM-2094 / Operation and Maintenance Manual
Jet-Ex 5D / Series 500285 / Generator Set
Generator and Controls
See section 2-4 for all figures referenced in this section.
Trouble, Symptom and Condition
1. Generator will not build up
voltage when SPEED
CONTROL toggle switch S406
(10, Figure 4) is placed in
RATED RPM position.
November 1, 2000
Revised 03/01
Probable Cause
a. Voltage build-up fuse F405
is blown.
b. Defective excitation rectifier
CR417 and/or CR418.
c. Defective capacitor C403.
d. Defective flyback diode
CR419.
e. Generator revolving field
L406 defective.
f. Defective generator
armature G402.
g. Voltage regulator fuse F403
is blown.
Test, Check, and Remedy
Replace voltage build-up fuse
(5, Figure 5). Proceed to Step b
to determine cause of blown
fuse.
Check excitation rectifiers ( 3,
Figure 5) 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.
Check capacitor (12, Figure 5)
with an ohmmeter to see if it is
good. If defective, replace it;
otherwise proceed to Step d.
Check diode, on brushholder
mounting bracket, with an
ohmmeter to see if it is good. If
defective, replace it; otherwise
proceed to Step e.
Locate yellow and red-orange
wires on the right terminal strip
at lower rear of control panel.
Disconnect the yellow and
red-orange wires which go down
to the generator. Refer to
connection diagrams in Chapter
5.
Measure resistance between
these two wires. It should be 10
to 11 ohms. If reading indicates
an open, short or lower than
normal resistance, proceed to
Step f.
If check of the generator
revolving field (Step e. above)
revealed no trouble, the
generator stator is defective.
Send unit to overhaul.
Replace voltage regulator fuse
(6, Figure 5). Proceed to Step
h. to determine reason for blown
fuse.
Chapter 2-5
Page 5