Tweco Max 300 w-TD-750 - Manual (Page 49)

Manual 0-2557 43 APPENDIX
APPENDIX I: SEQUENCE OF OPERATION BLOCK
DIAGRAM
ACTION
ON/OFF switch
to OFF
RESULT
All indicators off.
ACTION
RUN/SET switch
to RUN.
RESULT
Gas flow stops.
GAS indicator off.
Power circuit ready.
Fan off.
ACTION
Torch moved within
transfer distance of workpiece.
RESULT
Main arc transfer.
Pilot arc off.
PILOT indicator off.
DC indicator still on.
ACTION
Torch deactivated (by torch switch
release or by remote device).
RESULT
Main arc stops. Pilot stops.
(Power supply enable signal removed.)
DC indicator off.
PILOT indicator off.
NOTE - If torch is activated during
post-flow, pilot arc will immediately restart.
If torch is within transfer distance (3/8 in) of
workpiece, main arc will transfer.
After post-flow:
Gas solenoid closes, gas flow stops.
GAS indicator off.
Fan off.
ACTION
Open external
disconnect.
RESULT
No power to system.
ACTION
Close external
disconnect switch.
RESULT
Power to system.
ACTION
RUN/SET switch
to SET.
RESULT
Gas solenoid open,
gas flows to set pressure.
GAS indicator on.
Fan on.
ACTION
Torch moved away
from work (while
still activated).
RESULT
Main arc stops.
Pilot arc auto-
matically restarts.
PILOT indicator on.
PILOT ARC
ACTION
ON/OFF switch
to ON.
RESULT
AC, TEMP, PIP
indicators on.
Pilot disabled during
pre-flow.
ACTION
Protect eyes and
activate torch
RESULT
Gas flows
GAS indicator on
Fan on
After gas pre-flow:
DC indicator on.
Power supply enabled.
HF relay closes.
Pilot arc established
PILOT indicator on.
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