ESAB ESP-150 Manuel D'instruction page 149

SECTION 4
Do NOT operate the unit with the
cover removed.
Do NOT apply power to the unit while
holding or carrying the unit.
Do NOT touch any torch parts with
power switch on.
Position the ESP-150 at least 10 feet
(3 meters) from the cutting area.
Sparks and hot slag from the cutting
operation can damage the unit.
6. The cutting arc will extinguish at the end of the cut; however, the torch switch
should be released to keep the pilot arc from reigniting.
7. When cutting operation is completed, wait a few minutes before placing the
POWER switch to the OFF position so that the cooling fan has time to
remove the heat from the unit. Then shut off the primary power at the main
disconnect switch.
correct
With a positive cut angle, the top dimension is slightly less than the bottom
dimension. With a negative cut angle, the top dimension is slightly greater than
the bottom dimension. The cut angle is controlled by the standoff (arc voltage),
cutting speed and cutting current. If the cutting speed and the cutting current are
correct and the part has an excessive positive angle, then the standoff is too
high. Begin lowering the arc voltage in increments of 5 volts, observing cut
squareness. There will always be slight top edge rounding of the part when using
Nitrogen.
The optimum torch height is a point just before the part begins to develop a
negative cut angle. To expand upon the other two variables; with the correct torch
standoff, excessive cutting speed will result in a positive cut angle; insufficient
cutting speed will produce a negative cut angle. If the cutting current is too high or
low a positive cut angle will be produced.
Arc Voltage/Standoff - Interactive parameters that are proportional. The higher the
torch above the plate (standoff), the higher the operating voltage required and vice
versa.
Lag Lines - These lines appear on the cut surface. They are of assistance in
determining if your process parameters are correct.
143
too fast
Fig. 16 - Effect of Cutting Speed
OPERATION
too slow