Tweco PWH-M 2A - Manual (Page 21)

Operation 3-3 Manual 0-2005
3) Turn the system on.
4) Set the gas supply pressure regulator at 30 psig.
Adjust the gas flow rates as required (see Table
3-A).
5) Purge for approximately 3 minutes by letting
the plasma gas run. This will remove any con-
densation of moisture that may have accumu-
lated in the torch while it was shut down.
NOTE
Only the plasma gas line needs to be purged.
6) Select the welding mode.
7) Set the current to the selected amperage level.
The torch is now ready for operation.
WARNING
Read and understand the precautions listed in
the front of this manual. Be sure the operator is
equipped with proper gloves, clothing and eye
protection and that proper ventilation is pro-
vided.
3.2. HAND TORCH OPERATION
1) Pick up the torch and set the welding system to
the operating mode.
CAUTION
The pilot arc is established at this time. Be care-
ful of the direction the torch tip is pointed in so
as not to get burned.
2.) Lower the welding helmet and position the
torch at the beginning of the weld zone. The
light from the pilot arc will help to find this
position. Hold the torch approximately 3/16
inch from the workpiece and activate the con-
trol switch. When the welding arc transfers,
adjust the torch standoff and amperage until the
desired penetration is achieved. Move the torch
along the line of weld at a speed to coincide
with the weld puddle to achieve the desired
weld quality.
3) Deactivate the control switch.
4) Switch the welding system to the standby mode
(post purge).
5) Wait 5 minutes before shutting the system down
to allow the torch to cool.
3.3. MACHINE TORCH
OPERATION
1) Locate the torch at the required starting posi-
tion for the weld. Adjust the height as required.
2) Activate control switch.
3) Rate of travel of the torch will depend on the
material and type of weld. This will have to be
determined by the operator.
4) After the weld is completed, deactivate the con-
trol switch.
5) Put the welding system in the standby mode
(post purge).
6) Wait 5 minutes before shutting the system down
to allow the torch to cool.