Tweco 400 XT Ultra-Cut Plasma Cutting System - Manual (Page 157)

ULTRA-CUT 400 XT
Manual 0-5275 APPENDIX A-�9
Arc starter without Spark Gap (Ultra-Cut)
1. Check for power to the RAS 1000XT’s Ignition Module during the 15 seconds following preflow (ignition phase). Arc
starter power comes through the rear panel circuit breaker CB�, make sure it isn’t tripped.
a. During the ignition phase, measure for 120 VAC at the input terminals marked 120 VAC on the Ignition module, a gray
rectangular box with screw terminals on one side.
WARNING!
Do not let the meter probes (or your hands) come in contact with the other terminals marked Hb and Ho or the other
end of the wires connected to them. These can have 10,000 volt pulses which can cause physical harm and will
damage your meter.
2. If 120 VAC is not present go to step 3.
a. If 120 VAC is present and still no spark, the Ignition Module may be bad.
3. 120 VAC to the remote Arc Starter comes from J59-7 & 9 on the power supply rear panel and connects to J5�-7 & 9 on
the RAS1000XT. Remove the cable from J59 and during the ignition phase measure for 120 VAC between pins 7 & 9.
a. If 120 VAC is present problem is in the cable to the RAS 1000 XT or the J5� connector and internal harness in the
Arc Starter.
b. If 120 VAC is present proceed to the next step.
�. 120 VAC to J59 comes from the relay board J�-3 with return on pin 11. On the Relay board, RF ON LED, D23, should be
on during the igniting phase. If it is not skip to the next step.
a. If D23 is on and there is not 120 VAC at J�-3 & 11 then the Relay board is bad.
Either Arc Starter
5. /RAS ON signal not on. CCM sends active low signal “ /RAS ON” over the �0 pin ribbon cable on pin 1� to the Relay &
Interface board. On the relay board RAS Control relay (K2) closes (RF ON LED, D23 on) sending 120 VAC to J�-3 with
return on J�-11. From here it either goes to the HF transformer T2 (AC200XT) or to J59 as described above.
a. Measure the signal “/RAS ON” on pin 1� of the �0 pin ribbon cable relative to TP1 on either the CCM I/O board or the
Relay board. If it is low (less than 1V) skip to step �. Otherwise continue this step.
NOTE
If the CCM thinks there is already a pilot it would not enable the HF. Pilot board has a current sensor
that sends a differential analog pilot current level signal to the Relay board which in turn passes that
signal to the CCM. On the Relay board D11 LED “Pilot Current Detected” or just “PILOT” lights if it sees
a signal from the pilot board.