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PARALLEL OPERATION
The Invertec’s are operable in parallel. For best results, the currents of each machine should be rea- sonably well shared. As an example, with two machines set up in parallel for a 300 amp procedure, each machine should be set to deliver approximately 150 amps, not 200 amps from one and 100 amps from the other. This will minimize nuisance feedback conditions. In general, more than two machines in par- allel will not be effective due to the voltage require- ments of procedures in that power range.
To set machine outputs, start with output control pots and arc force pots in identical positions. Adjust out- puts and arc forces to maintain current sharing while establishing the proper output current.
OVERLOAD PROTECTION
The machine is electrically protected from producing high output currents. Should the output current exceed 290A, an electronic protection circuit will reduce the current to less than 200A. The machine will continue to produce this low current until the pro- tection circuit is reset. Reset occurs when the output load is removed.
THERMAL PROTECTION
Thermostats protect the machine from excessive operating temperatures. Excessive temperatures may be caused by a lack of cooling air or operating the machine beyond the duty cycle and output rating. If excessive operating temperature should occur, the thermostats will prevent output voltage or current.
Thermostats are
