Hobart JET-EX 4 Operation And Maintenance Manual page 82

OM-2049
TROUBLESYMPTOM
AND CONDITION
GENERATOR AND CONTROLS
5. Load contactor
opens as soon
as contactor
close switch is
released from
its top (spring-
loaded) position
6. Load contactor
opens during
power delivery.
3-1
Page 20
PROBABLE CAUSE
A. Defective contactor
close switch (S408).
B. Defective resistor R406
(located in back of
control panel, on
terminal strip beneath
base of voltage sensing
relay. See connection
diagram 488860)
C. Defective diode CR402.
D. Load contactor (K402)
defective.
A. Contactor opening could
have been normal because
of an overvoltage
condition.
TEST, CHECK, AND/OR
REMEDY
A. Connect a jumper lead between
terminals 1 and 2 (orange-red
and yellow-red wires) on the
contactor close switch (11,
Fig. 2). If the load contactor
now remains closed, replace
contactor close switch.
B. Using an ohmmeter, check
resistor R406 for proper
resistance (7.5 ohms). If
an open circuit is indicated,
replace resistor.
C. This diode is also located on
the terminal strip beneath the
voltage sensing relay. Using
an ohmmeter, check this diode
for an open circuit. If diode
is defective, replace it.
D. If no fault was found in steps
4A, B, and C above, the load
contactor (22, Fig. 1) is
defective. Replace load
contactor.
A. Resume operation and closely
observe voltmeter (6, Fig. 2)
for evidence of overvoltage.
If contactor opens when no
overvoltage condition exists,
proceed to Step B.
May 20/89