Miller Electric OM-494 Welding System User Manual


 
OM-494 Page 41
8-10. Circuit Protection
Ref. 802 300 / Ref. 802 292-A
Y Stop engine.
. When a circuit breaker or fuse opens,
it usually indicates a more serious
problem exists. Contact Factory Au-
thorized Service Agent.
1 Fuse F1
2 Fuse F2
3 Fuse F3
4 Fuse F4
Open front panel.
Fuse F1 protects the exciter excitation
winding. If F1 opens, there is no weld or
generator power output on both sides.
Fuse F2 protects the exciter main field ex-
citation winding. If F2 opens, there is no
weld output on both sides.
Fuse F3 protects Welder A (left) control
board PC1. If F3 opens, Welder A (left) weld
output stops.
Fuse F4 protects Welder B (right) control
board PC1. If F4 opens, Welder B (right)
weld output stops.
5 Circuit Breaker CB5
6 Circuit Breaker CB6
7 Circuit Breaker CB7
8 Circuit Breaker CB8
Circuit Breaker CB5 protects the 24 volt
and 115 volt ac output to Welder A (left) re-
mote receptacle RC9. If CB5 opens, Weld-
er A (left) RC9 24 and 115 volt ac output
stops.
Circuit Breaker CB6 protects the 24 volt
and 115 volt ac output to Welder B (right) re-
mote receptacle RC8. If CB6 opens, Weld-
er B (right) RC8 24 and 115 volt ac output
stops.
Circuit Breaker CB7 protects field current
regulator board PC4. If CB7 opens, weld
and generator power output on both sides
stops.
Circuit Breaker CB8 protects the generator
field flashing circuit. If CB8 opens, weld and
generator power output may continue if
generator maintains excitation. Weld and
generator power output stops if generator
requires field flashing circuit to restore ex-
citation.
Press button to reset circuit breaker.
9 Fuses F11, F12, F13, F21, F22, F23
These fuses protect the weld stator wind-
ings. If fuse F11, F12, or F13 opens, Welder
B (right) side output is erratic or low. If fuse
F21, F22, or F23 opens, Welder A (left) side
output is erratic or low.
10 Thermostats TP3 And TP4 (Internal
Not Shown)
Thermostat TP3 protects Welder A (left)
SR2 rectifier and TP4 protects Welder B
(right) SR3 rectifier from overheating. If
TP3 or TP4 opens, Welder A (left) or Welder
B (right) weld output stops and the High
Temp. Shutdown light goes on. Wait fifteen
minutes for module to cool and thermostat
to automatically reset. Reduce amperage,
voltage, or duty cycle before welding.
Tools Needed:
3
4
7
8
5
6
1
2
9