Lincoln Electric IDEALARC IM402-B - Manual (Page 12)

OPERATION
Safety Precautions
Be sure the Idealarc 250 is properly installed, and that
all accessories are properly hooked up before
attempting operation.
DUTY CYCLE
This machine is rated at a 30% duty cycle at 250
amps or 50% duty cycle at 200 amp output. Duty
cycle is based on a 10 minute period. Therefore,
the welder can be loaded at 200 amperes for 5
minutes out of each 10 minute period. Higher duty
cycles can be used at lower currents; see rating
plate information.
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CONTROL OPERATION
A. Current Control Handle
Rotating the hand wheel raises and lowers the
output current allowing the operator to dial the
desired current. Clockwise rotation reduces
the current while counter-clockwise rotation
increases the current. Turning the current
control handle also drives the output pointer at
the bottom of the nameplate which indicates
the stick welding current at NEMA arc volts.
B. Polarity Switch
Turn the arc polarity switch in the upper right
hand corner of the case front to AC, DC(-) or
DC(+) as required for the particular application.
DO NOT CHANGE POLARITY SWITCH
WHILE WELDING. Doing this can seriously
damage the switch.
C. TIG Welding
The Idealarc 250 with the optional Hi-Freq is an
inexpensive equipment combination for part-
time production or repair TIG welding of alu-
minum, magnesium, thin stainless steel and
many space-age metals. The Idealarc 250 can
be used for normal stick electrode welding with
the Hi-Freq attached.
Reduce the Idealarc 250 duty cycle by 50%
when AC TIG welding, i.e., the welder should be
operated for only two and one half minutes out
of every ten at rated current of 200 amperes.
The Hi-Freq includes high frequency generator,
gas valve and needed controls. It operates on
115V, 50/60 Hz AC power.
NOTE: The Hi-Freq unit includes an R.F.
bypass capacitor kit for power source protec-
tion. Installation instructions are in the kit.
(When using the Idealarc 250 with any other
high frequency equipment, an R.F. bypass
capacitor must be installed. Order Kit T12246.)
To provide protection, the welder grounding
stud or frame must be connected to ground
(see instructions on grounding in Machine
Installation section). Also follow the grounding
instructions given in the Hi-Freq Instruction
manual.
ELECTRIC SHOCK can kill.
• Do not touch electrically live parts or
electrode with skin or wet clothing.
• Insulate yourself from work and
ground.
• Always wear dry insulating gloves.
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FUMES AND GASES can be dangerous.
• Keep your head out of fumes.
• Use ventilation or exhaust to remove
fumes from breathing zone.
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WELDING SPARKS can cause fire or
explosion.
• Keep flammable material away.
• Do not weld on closed containers.
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ARC RAYS can burn eyes and skin.
• Wear eye, ear and body
protection.
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See additional warning information at the
front of this operatorʼs manual.
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WARNING
CAUTION