| Problem |
Possible Cause |
Solution |
| Circuit breaker trips when start/stop switch is energized |
Shorted DC bus |
With power removed, ohm check across wires 6 and 28. Should read 20kOhms in one direction and 50-100Ohms in the opposite direction. If not correct, proceed to the next step. |
| Shorted rectifier |
Check rectifier with VOM. Replace rectifier if shorted. Otherwise proceed to next step. |
| Inverter fault |
Make sure that output power control is turned fully counter-clockwise. Proceed to next step. |
| Shorted filter capacitor |
Replace defective filter capacitor |
| Defective SCR |
Ohm check SCRs. Replace if defective. |
| Start button is pushed but nothing happens |
Interlock circuit open |
Check to be sure that interlock circuit is connected from the treater station to the power supply. Place a temporary jumper on the interlock terminals and try to energize start button. If okay, remove jumper and locate defective interlock |
| Loose wire or connection |
With the power off, lightly tug on interlock wiring at the power supply and treater station. Ensure a good connection. |
| No control voltage |
Check for blown control transformer fuse. |
| Circuit breaker trips when start button is energized and output is adjusted clockwise |
Short circuit at treater station |
Disconnect power. Disconnect high voltage secondary lead from transformer. If unit runs, check for short circuit in output cable, or treater station. If unit still trips, proceed to next step. |
| Defective high voltage transformer |
Replace high voltage transformer. |
| Incorrect tap setting on high voltage transformer |
Change tap to X4 and try again. |
| Shorted SCRs or diodes in power supply |
Disconnect output leads of power supply to high voltage transformer and start unit. If unit trips measure DC bus voltage wires 6 to 28. Should be approx 175VDC for power supplies less than 2.5 kW and 355VDC for power supplies 2.5kW and larger. Measure DC voltage from wires 6 to 26 and 28 to 27. Approx 1/2 the DC bus voltage should be read between these wires. |
| Defective control board |
Replace control board and restart power supply. |
| Defective watt meter board |
Replace watt meter board and restart power supply. |
| Output power is adjusted clockwise, but nothing happens. |
Defective control board |
Replace control board and restart power supply. |
| Defective watt meter board |
Replace watt meter board and restart power supply. |
| No meter reading with unit operating. |
Defective panel meter |
If power supply can be heard, check for good connections to meter. If okay replace meter. |
| Defective watt meter board |
Replace watt meter board and restart power supply. |
| Voltage limit |
Power supply is operating at maximum safe output voltage. |
If unable to achieve full power, change high voltage transformer tap and check again. Check for proper electrode gap and alignment. |
| Current trip |
Impedance mismatch |
Check electrode gap. Retap output transformer. See impedance matching section of your manual |
| High voltage failure at treater |
With power off, remove high voltage wire from output transformer secondary. Re-tap the transformer to X0-X4. Start the power supply. Power supply should go into a frequency limit with no current trip. |
| High voltage transformer failure |
With power off, remove output wires from the terminal strip in the power supply. Start the power supply. Power supply should go into a volt limit with no current trip. |
| Defective SCR |
Ohm check SCRs. Replace if defective. |
| Defective control board |
Replace control board and restart power supply. |
| Defective watt meter board |
Replace watt meter board and restart power supply. |
| Power supply stops intermittently |
Zero speed fault |
Make sure roll is turning freely and is not slipping when the web material is running though it. All it takes is a momentary opening of the interlocks to shut the power supply down |
| Intermittent or bad interlock or switch |
See interlock circuit open above. |