Hobart Jet-Ex 5D Operation And Maintenance Manual page 66

OM-2094 / Operation and Maintenance Manual
Jet-Ex 5D / Series 500285 / Generator Set
Generator and Controls (continued)
See section 2-4 for all figures referenced in this section.
Trouble, Symptom and Condition
Generator will not build up
voltage when SPEED
CONTROL toggle switch S406
(10, Figure 4) is placed in
RATED RPM position
(continued)
2. Generator builds up to only a
low voltage when SPEED
CONTROL toggle switch S406
(10, Figure 4) is place in
RATED RPM position
3. Generator builds too high a
voltage.
4. Load contactor will not close
when CONTACTOR
CONTROL toggle switch S408
(7, Figure 4) is placed in closed
position. Engine running
normally, voltage normal, no
load applied to output cable.
Chapter 2-5
Page 6
Probable Cause
h. Defective rectifier CR401.
i. Generator voltage regulator
VR402 defective.
a. Defective excitation rectifier
CR417 and/or CR418.
b. Generator voltage regulator
VR402 defective.
a. Defective SPEED
CONTROL toggle switch
S406 (10, Figure 4).
b. Defective blocking rectifier
CR401.
c. Generator voltage regulator
VR402 defective.
a. Defective CONTACTOR
CONTROL toggle switch.
b. Defective load contactor
K402.
Test, Check, and Remedy
Use ohmmeter to check rectifier
CR401 (11, Figure 5). Replace
rectifier if defective.
Replace voltage regulator (2,
Figure 5).
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 b.
Replace voltage regulator (2,
Figure 5).
Use ohmmeter to check SPEED
CONTROL toggle switch.
Replace switch if defective.
Use ohmmeter to check
blocking rectifier (11, Figure 5)
Replace rectifier if defective.
Replace voltage regulator (2,
Figure 5) with a voltage
regulator known to be good, and
resume operation of generator
set. If new voltage regulator
produces normal operating
voltage, send old voltage
regulator to factory for service.
Momentarily connect a jumper
lead between terminals with red
and yellow wires on the
CONTACTOR CONTROL
toggle switch. If the load
contactor closes momentarily,
replace switch.
If load contactor (10, Figure 1)
will not close when contactor
close switch is jumpered, it is
likely that the contactor is
defective. Replace contactor.
November 1, 2000
Revised 03/01