Hobart JET-EX 4 Operation And Maintenance Manual page 81

TROUBLESYMPTOM
AND CONDITION
GENERATOR AND CONTROLS
3. Generator volt-
age builds too
high a voltage.
4. Load contactor
will not close
when contactor
close switch
(S408) is
operated. Engine
running normally
voltage normal,
no load applied
to output cable.
May 20/89
PROBABLE CAUSE
A. Voltage sensing relay
(K404) defective.
Relay coil is open or
contacts 1-7 and 3-9
stuck in closed
position.
B. Defective voltage
regulator (VR402).
CAUTION: DO NOT OPERATE THE GENERATOR SET TO
DELIVER POWER TO AN AIRCRAFT WHEN ANY PROTEC-
TIVE DEVICE OR OTHER COMPONENT IS JUMPERED.
A. Defective contactor
close switch (S408).
B. Defective load
contactor (K402).
C. Overvoltage relay
(K403) defective.
TEST, CHECK, AND/OR
REMEDY
A. Remove voltage sensing relay
(5, Fig. 3) from its socket
and apply 24V DC to the coil
(terminals A and B). Using
an ohmmeter, check to see that
contacts open and close
properly. If voltage sensing
relay is defective, replace it
If not, proceed to Step B.
B. Replace voltage regulator
(2, Fig. 3) 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.
A. Momentarily connect a jumper
lead between terminals 4 and 5
(red and yellow-red wires) on
the contactor close switch (11,
Fig. 2). If the load contactor
closes momentarily, replace
contactor close switch.
B. If load contactor (22, Fig. 1)
will not close when contactor
close switch is jumpered, it
is likely that the contactor is
defective. Replace contactor.
C. Connect a jumper lead between
terminals T and P on the
overvoltage relay (2, Fig. 3).
If contactor will now close,
replace overvoltage relay.
OM-2049
3-1
Page 19