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SAFETY PRECAUTIONS
WARNING
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.
FUMES AND GASES can be danger-
ous.
• Keep your head out of fumes.
• Use ventilation or exhaust to remove
fumes from breathing zone.
WELDING SPARKS can cause fire or 
explosion.
•Keep flammable material away.
•Do not weld on closed containers.
ARC RAYS can burn eyes and skin.
•Wear eye, ear and body protection.
See additional warning information at front of this operator’s manual.
GENERAL DESCRIPTION
The
Primary input voltage taps are selected by a single movable link on the reconnect panel. Main trans- former auxiliary windings power the firing circuit and fan motor. The control auxiliary transformer has a sin- gle, wide range primary and is not reconnectable.
The Fan As Needed feature is activated by an output current of 20 Adc or a thermostat on the main trans- former iron.
An independent safety circuit on the Control board monitors the voltage peaks and opens the input con- tactor if the limit is exceeded. The green Safe Output light indicates when the machine output voltage is within the safe operating range.
Other indicator lights include the amber Thermal light that signals when the long term output current limit has been exceeded. This limit is determined by a ther- mostat sensing the temperature of the negative output lead from the secondary coils. The white Power light indicates when the Control board is energized. The three lights are high intensity LEDs for improved visi- bility in daylight.
The Output Power display uses high intensity LEDs to indicate the percentage of full rated output the machine is supplying.
Two additional thermostats protect the machine in the case of fan failure or blocked air flow. The SCR heat sink thermostat responds first to loss of air flow at nor- mal output loads. This thermostat will disable the machine output. The transformer iron rear thermostat senses that the lamination (and thus the coil insula- tion) is over heating (which can happen even if the output is disabled). This thermostat will interrupt power to the Control board causing the input contactor to open until the iron cools.
The only user controls are an
DESIGN FEATURES - ALL MODELS
SPECIFICATIONS, DESIGN FEATURES AND ADVANTAGES
Case parts are predominantly stainless steel, the PC boards are potted in trays, the controls are sealed, all machine coils are copper and the whole transformer is varnish dipped to maximize environmental withstand capability. The coils are all conservatively rated for long life.
The