Hobart 6T28-600CL Operation And Maintenance Manual page 39

OM-2244 / Operation and Maintenance Manual
DCS-600/ Series 500082 / Solid State Transformer-Rectifiers
2. Over-voltage/Overload trip
malfunction is in unit's internal
circuitry.
3. Fan not operating (also see
causes and remedies under
"Machine will not start")
Trouble, Symptom, Condition
Voltage on GPU Case
1. Operator gets shock when
machine case is touched
Output Current Varies Without Voltage Change
December 15, 2014
c. Ambient temperature too high
d. Ventilation blocked
e. Fan not operating
f. Shorted output
a. Control circuit board failure
b. Loose connections in voltage
control circuit
c. Starting current potentiometer
(R13) open
a. Blown fuse (F1)
b. Fan control thermostat defective Place a jumper wire across the
Note: A properly operating fan thermostat will turn on the fan at 100°F
and keep the fan running until 80° F is reached at heat sink.
c. Broken lead or connection to fan
motor
d. Fan motor defective
Probable Cause
a. Case of machine not grounded
Operate at reduced loads when
temperature exceeds 104° F (40°
C) or improve cooling ambient.
Check that air intake and exhaust
openings are not obstructed.
Check fuse F1 on the fan shroud. If
it is good, disconnect the fan motor
leads and apply 115 VAC directly
to fan motor. Replace fan motor if it
fails to operate or if its bearings are
defective.
Reset electronic overload.
Refer to detail troubleshooting
instructions.
Check for loose connections.
Tighten and secure as required.
Replace potentiometer.
Replace fuse.
overheated thermostat. If fan then
runs, replace thermostat.
Repair wiring as necessary.
Disconnect fan motor leads and
apply 115 VAC directly to fan
motor. If it fails to operate, replace
it.
Test, Check, and/or Remedy
Ground machine case to an earth-
type ground if utility ground is
already connected. Connect the
normal safety ground and recheck
if "utility" ground had not been
connected.
Chapter 2-1
Page 7