Effect of Transformer Winding Reactance on Performance of Three Phase Uncontrolled Rectifier

 Effect of Transformer Winding Reactance

• The effect of transformer winding reactance on the performance of output voltage / current is explained here. 
• The conduction of diode D1, D2 and D3 and resulting flow of current is shown in the figure A. 
• It should be noted that the load current flows in the diode D1 decreases instantly from I_dc to zero. 
• Similarly the current in diode D2 rise instantly from zero to I_dc. 
• This sudden change of current is prevented by the inductance of the transformer winding.

• Due to inductive reactance of the transformer winding, self induced emf L_R (di_R/dt) and L_Y (di_Y/dt) induced in the respective transformer winding. 
• This induced emf prevents any rise or decrease of current instantly. 
• The anode voltages of the diodes are same and total current remains constant during overlapping period. 
• Therefore one diode pickups load and other drops it.

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