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THEORY OF OPERATION
PROTECTIVE CIRCUITS
Protective circuits are designed into the Square Wave TIG 355 to sense trouble and shut down the machine before the trouble damages the internal machine com- ponents. Both thermal protection and current over- load are included.
THERMAL PROTECTION
Thermostats protect the machine from excessive operating temperatures. Excessive operating temper- atures may be caused by a lack of cooling air or by operating the machine beyond the duty cycle and out- put rating. If excessive operating temperature should occur, causing the secondary thermostat to open, the input contactor will shut the machine off. If the prima- ry thermostat opens, the machine will stay on (pilot light, meters and fans running), but output current will be limited to no more than 5 amps.
Once the machine cools sufficiently the thermostats are
OVERLOAD PROTECTION
The machine is electronically protected from produc- ing excessively high output currents. Should the out- put current exceed approximately 400 amps, an elec- tronic circuit will reduce and limit the output current. The machine will continue to limit the output current until the overload is removed.
SQUARE WAVE TIG 355