Tweco PAK 44G - Manual (Page 40)

APPENDIX 34 Manual 0-2686
APPENDIX II: SEQUENCE OF OPERATION BLOCK
DIAGRAM
ACTION
1. Close external disconnect switch.
Red AC POWER indicator ON.
2. ON/OFF switch to ON.
RESULT
1. Amber ready indicator ON.
2. Coolant pressure switch closes.
3. Gases flow.
After two seconds:
4. Gas flow stops.
ACTION
1. RUN/SET switch to SET.
RESULT
1. Gas valves open, gases flow to
purge system and allow setting
of pressures.
2. Power circuits disabled.
ACTION
1. RUN/SET switch to RUN.
2. Select cutting amps with
CURRENT knob.
RESULT
1. Gas flow stops.
2. Power circuits ready.
System OFF
System READY
ACTION
1. Lower helmet and close control switch on torch (or remote
control assembly).
RESULT
1. Gases flow and gas pressure switches close.
2. Main contactor closes. Red DC indicator ON.
After two seconds:
3. High frequency ON
4. Pilot arc relay closes.
5. Pilot arc comes ON.
PILOT ARC
ACTION
1. Torch moved away from workpiece,
or workpiece burns away under
torch.
RESULT
1. Gouging Arc stops.
2. Current sensing circuit turns ON high
frequency and pilot arc.
ACTION
1. Torch brought close (within 1/2 inch)
to workpiece.
RESULT
1. Arc transfers to workpiece to
establish Gouging Arc.
2. Current sensing circuit turns OFF
pilot arc and high frequency.
ACTION
1. Open control switch on torch (or
remote control assembly)
RESULT
1. Red DC power indicator OFF.
2. Pilot arc stops.
After two seconds:
3. Gas flow stops.
System READY Gouging Arc
NOTE:
To shut down system, allow fan and pump to run for
five minutes and then move On/OFF switch to OFF. Be
sure to open external disconnect switch.
A-02105