THREE PHASE WELDING RECTIFIER CIRCUIT WITH WORKING PRICIPLE

Three phase welding rectifier circuit working 

Introduction:- A three phase welding rectifier is used in places where very smooth and perfect welding work is required. It consist of three phase step down transformer, rectifier and current controlling saturable reactor.

Circuit description:- A three phase  transformer is used for step down three phase 400 volt to 3 phase 100 v ac for welding rectifier. In a three phase transformer there are three winding in primary connected in star/delta connection and three secondary winding also connected in star / delta connection. A three phase bridge configuration is used, as shown in diagram for ac to dc conversion.

for output current contolling saturable reactor is used.saturable reactor has two winding one is used in series with output dc line and other winding is connected dc power source with variable resistance to control output current.

A  MCB, Contactor and Over Load relay is used  in control circuit to switch on power to welding transformer and protection from over load. one cooling fan is also used for cooling of transformer not shown in diagram. Start and stop button is provided for on/off contactor.

Controlling Current:- When controlling current is less saturable reactor reactance is more causing low output current. As control current trough reactor is increases the reactor reactance decreases causing more output current.


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