Miller Electric Miller DU-OP Circuit Protection, Thermostats TP3 And TP4 Internal − Not Shown

8-11. Circuit Protection

1 2

5

Tools Needed:

3 4

7

8

6

9

YStop engine.

.When a circuit breaker or fuse opens,

it usually indicates a more serious problem exists. Contact Factory Au- thorized Service Agent.

1Fuse F1

2Fuse F2

3Fuse F3

4Fuse 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.

5Circuit Breaker CB5

6Circuit Breaker CB6

7Circuit Breaker CB7

8Circuit 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

Ref. 802 300 / Ref. 802 292-A

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.

10Thermostats 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.

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