Troubleshooting; Tuning Chart - Miller Electric Intellifire 250 Owner's Manual

5-9. Troubleshooting

Trouble
No heat output.
No heat output; fan motor continues to run.
Low heat output.
Current Source Fault LED (red) on.
Over Frequency Fault LED (red) on.
Under Frequency Fault LED (red) on.
Current Fault LED (red) on.
Tank Voltage Fault LED (red) on.
Line Voltage Fault LED (red) on.
Ground Fault LED (red) on.
Load Fault LED (red) on.
Over Temperature Fault LED (yellow) on.
Current Source Limit LED (yellow) on.
Over Frequency Limit LED (yellow) on.
Under Frequency Limit LED (yellow) on.
Current Limit LED (yellow) on.
Tank Voltage LED (yellow) on.

5-10. Tuning Chart

Voltage* Current (Amperage)*
High Low
High Low
High Low
Low High
Low High
Low High
*High voltage > 650 V rms; Low voltage < 450 V rms; Operating current range: 0 to 750 A rms
The power source is factory set for 4.5 mfd, but is capable of being set for 6 mfd. If a certain application requires the higher capacitance setting, remove
insulator from front capacitor and connect with supplied hardware.
OM-184 227 Page 16
Replace building line fuse or reset circuit breaker.
Secure head/coil connecting plate to power source connecting block (see Section 3-2).
Check and replace Power switch if necessary.
Connect power source to proper input voltage or check for low line voltage.
Safety interlock switch open. Reinstall wrapper (see Section 5-4).
Thermostat(s) TP1, TP2, and/or TP3 open (overheating). Allow fan to run; the thermostat(s) will close
when the unit has cooled (see Section 5-2).
Check tuning of induction heating output system.
Turn power off and back on again to power source one time. If fault does not clear, contact authorized
Factory Service Agent.
Check for shorted coil or blanket.
Check for open circuit coil or blanket.
Check for shorted turn(s) in coil or blanket.
Check for unloaded (empty) coil.
Check for arcing between turns.
Check input line voltage.
Check for output path to ground.
Check for human path to ground.
Check for loose coupling between coil or blanket and workpiece or pipe.
Check door switch.
Check for fan operation.
Clean unit.
Check coupling between coil and load.
Check for correct tank capacitance.
Check for shorted turns.
Check for correct tank capacitance.
Check tank capacitance.
Check tuning of system (see Section 5-10).
Y Energizing contactor without at least 1 tuning capacitor in output circuit will damage power
source.
DO NOT operate power source without at least 1 tuning capacitor in output circuit.
Frequency (KHz)
Low
High
Mid-Range
Low
High
Mid-Range
Remedy
Corrective Action
Lower inductance or decrease matching transformer turns ratio
Add capacitance
Decrease matching transformer turns ratio and add capacitance
Lower capacitance
Increase matching transformer turns ratio, or lower capacitance and
increase inductance
Increase matching transformer turns ratio and lower capacitance