Tweco VA 4000S Ultra-Feed - Manual (Page 33)

ULTRAFEED VA 4000S
Manual No. 0-5135 4-7 OPERATION
4.07 Welding - 2 Step Operation
Refer to Figure 4-5.
Position the welding gun above the workpiece and de-
press the gun switch trigger. Depressing the gun switch
trigger enables the gas valve, wire feed motor, and power
source; the welding process begins. To end the weld, re-
lease the gun switch trigger which disables the gas valve,
wire feed motor, and power source.
NOTE
When the gun switch is released, gas will
continue to flow for approximately 0.5
seconds. This is a feature of the system and
is normal.
3. Push the PURGE switch of the feeder and adjust
the flow of shielding gas.
4. Push the INCH switch of the feeder and adjust
the wire feed speed to the desired value by means
of the wire feed speed control.
!
WARNING
If the gun switch is depressed, the electrode
(welding wire) is electrically “hot”. Do not
permit it to touch any metal or a welding arc
may be established which may be injurious to
someone’s eyes (flash) or skin (burn).
5. Adjust the voltage of the power source to the
desired value. The gun switch must be triggered
to close power source contactor.
WARNING
In semiautomatic or automatic wire welding, the
welding wire, wire reel (if used), input guide, feed
rolls, output guide, feedhead, and welding gun
metal parts are all ELECTRICALLY “HOT”.
Gun Trigger
Arc Established
Gas
Contactor
WireFeed
R
un
in
%
Postflow
Preflow
Ramp Rate
Art # A-09232
Figure 4-7: Welding - 2 Step Operation