Tweco 300 XT Auto-Cut 400V - Manual (Page 125)

AUTO-CUT 300 XT
Manual 0-5290 APPENDIX A-43
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 CB4, 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
J58-7 & 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 J58 connector and internal har-
ness in the Arc Starter.
b. If 120 VAC is present proceed to the next step.
4. 120 VAC to J59 comes from the relay board J8-3 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 J8-3 & 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 40 pin ribbon cable on pin
16 to the Relay & Interface board. On the relay board RAS Control relay (K2) closes (RF ON LED, D23 on)
sending 120 VAC to J8-3 with return on J8-11. 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 16 of the 40 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 6. 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.