Tweco Thermal Arc TA 500 User Manual
Page 39
Manual No 0-0470
4-5
Service
ACTION
1. Close all three external disconnect
switches (TA500, HE200,
Hi-Flow Water Shield)
RESULT
1. Red AC POWER light (LT3) on and
fan starts in TA500.
ACTION
1. ON/OFF switch (SW1) to ON.
RESULTS
1. HE200 starts to pump coolant to
torch via Supply Console
2. Coolant pressure reaches 100 psi.
3. Amber READY light (LT4) turns on.
4. Plasma gas and secondary gas
or water shield solenoids open
and gases (or water) flow.
After two seconds:
5. Gas (or water) flow stops.
ACTION
1. RUN/SET/PURGE switch
(SW6) to SET.
RESULTS
1. Plasma gas and secondary gas
or water solenoids open. Plasma
gas and secondary gas or water
flow so pressure can be set.
2. Power circuits disabled.
ACTION
1. RUN/SET/PURGE switch
(SW6) to PURGE.
RESULTS
1. Plasma gas solenoid only
opens allowing the plasma
line to be purged.
ACTION
1. RUN/SET/PURGE switch
(SW6) to RUN.
2. Select cutting amps with
CURRENT CONTROL knob.
RESULTS
1. Gas flow stops.
2. Power circuits ready.
ACTION
1. STOP button pressed.
RESULTS
1. Red DC POWER light off.
2. Pilot arc stops.
After two seconds:
3. Plasma gas and secondary
or water flow stops.
ACTION
1. Torch brought close (approximately
1/2 inch) to workpiece.
RESULTS
1. Arc transfers to workpiece to establish
CUTTING ARC.
2. Current sensing circuit turns off pilot arc.
3. Depending on the position of the PILOT
AUTO/MAN switch the arc starter will be
turned off by either relay CSR (AUTO) or
time delay relay (MAN).
4. 'Pre-start' saturating current turned on by relay CSR.
5. Standoff Control circuitry is energized by relay CSR.
6. Current regulating circuit is energized by relay CSR.
7. Hi-Flow Water Shield turned on by relay CSR.
ACTION
1. Protect eyes and press START
button.
RESULTS
1. Plasma gas and secondary gas
or water pressure switches close.
2. Main contactor closes. Red DC
POWER light on.
3. Reactor saturating current is
turned on. The amount of satur-
ating current depends on the
position of the NORMAL/SOFT
START/PIERCE switch (this
is for 'pre-start' only).
After two seconds:
4. Pilot arc relay closes.
5. Arc starter circuit energized.
6. Pilot arc turns on.
ACTION
1. Torch moved away from workpiece
or workpiece burns away
under torch.
RESULTS
1. CUTTING ARC stops.
2. Hi-Flow Water Shield shuts off
automatically.
PILOT AUTO/MAN switch in
AUTO position:
3. Pilot arc comes on until CUTTING
ARC is transferred or STOP
button is pushed.
PILOT AUTO/MAN switch in
MAN position:
3. No Pilot arc.
4. DC POWER light remains on,
gases continue to flow.
5. No cutting arc.
SYSTEM
READY
PILOT
SYSTEM READY