Tweco Troubleshooting Power Supply - Manual (Page 18)

18
2-3 Power Supply Overheated.
Inverter module(s) and pilot regulator (chopper) module have sensors
monitoring their temperature. An over temperature in either inverter, chopper or
torch coolant will turn on the front panel TEMP indicator however the torch
coolant system over temperature sets a different code.
Because the unit is 100% duty cycle it should never see an over temperature in
normal operation.
Causes for 2-3 code:
• Harness for CN12 on PCB5 plugged into CN17
• Failed fan
• Defective inverter or chopper module
• Defective power supply PCB
• Defective CCM
CN12
CN17 not used is some units. It is the same size and is right next to CN12. If
PCB5 has been replaced it can be plugged into CN17 by mistake.
This will show
2-3 code immediately at power on before the unit has been operated.
Inverter Fans
Power supplies have one (100A) two (150/200A) or three (300A) inverters.
Each inverter has a 24 VDC fan powered from a supply local to that inverter.
Inverter fans come on a few seconds after input power is applied. The delay is to
allow system to verify correct input voltage. Once on, the fans will run until there
has been no activity, no Start applied, no pilot or cut, for 7-8 minutes then the fan
control circuit will shut them off. Applying Start will turn fans back on. When
troubleshooting, turn power off then back on to be sure fan control circuit has not
timed out.
Check for air flow out the front panel louvers (left side) in front each inverter.
INV #1
INV #2
INV #3