Tweco Thermal Arc TA 500 - Manual (Page 30)

Operation 3-4 Manual No 0-0470
Figure 3-F Using a Square to set up the M200 Torch
2. To start a cut at the edge of the plate, line up the
torch away from the plate and press the START
button on the Control Panel. The pilot arc char-
acteristics will depend on which PILOT mode
is selected (see 3.1.12) and the position of the
SURFACE/UNDERWATER Switch (3.1.13).
The cutting arc will be established at the plate
edge as the torch approaches the plate.
3. Adjust the cutting speed for good cutting perfor-
mance, as indicated by a trailing arc of approximately
5 degrees (Fig. 3-G).
5 o Approx.
Figure 3-G Proper Cutting Speed Produces a Trailing
Arc of Approximately 5 Degrees
4. In some cutting operations, it may be desirable to
start the cut within the plate area rather than at the
plate edge. Piercing is not recommended in over 2-
inch (50 mm) thick material when using Water Shield.
When a lot of piercing is required, a special tip (Cat.
No. 8-6047) and end cap (Cat. No. 8-6057) should be
used. To pierce, set the NORMAL/SOFT START/
PIERCE switch to the PIERCE position (see 3.1.8).
NOTE:
The suggestions listed below should be followed
in all cutting operations:
1. At shut down wait five minutes before moving
the ON/OFF switch to OFF and opening the
main disconnect switch. This allows the Power
Supply and torch to cool down.
2. For maximum parts life, do not operate the pi-
lot arc any longer than necessary.
3. Remember that cutting current can be adjusted
at any time (see Instruction Manual for Stand-
off Control). Learn to change the current out-
put to provide a comfortable working speed
for the particular material being cut.
4. Use care in handling torch leads and protect
them from damage.