The Voltage Reducing Device for Engine Driven AC Arc Welder

Abstract

Newly developed voltage reducing devices are described for engine driven AC arc welders of both self and separate excitations.
Output voltage of the welder is regulated by changing the field current electronically with semiconductor elements.
Difficulty of rapid arc starting due to large field inductance is eliminated by using a condenser discharge circuit connected to the field winding. Thus, field current can rise very fast to shorten the arc starting time, that is, the buildup time of output voltage of welder. This buildup time is as small as 0.06 seconds which satisfies the Japanese Industrial Standard of voltage reducing device for transformer type AC arc welder.
Efforts are also made to protect the devices from the damage caused by the vibration of engine. As a result, high reliability and good performance are obtained.