Three Phase Full Wave Rectifier Using Six Diodes
In this circuit six diodes, Q3 transformer whose primary delta winding and secondary is star winding is used. The rectifier consist on D4, D5 and D6 are conducts during +ve half cycle of 3 phase - i/p supply, the diodes D1,D2 and D3 are conducts during the –ve half cycle. The upper three diodes D1,D2,D3 are produce –ve o/p while the diodes D4,D5 and D6 produce +ve o/p.
As clear from the figure that the +ve terminal of load is connected to the cathode of D4,D5 & D6 while the anode of these diodes are connected with i/p supply. The –ve terminal of load is connected with the anode of D1, D2 & D3, while the cathodes are connected with i/p supply. It may be seen that each secondary terminal is connected to the anode of one diode and cathode of the other diode. Thus diode D1 & D4 are connected to faze “A” of the secondary. However the diodes D1& D4 are connected to the same phase but do not conduct at the same time because the phase have +ve and –ve peaks at the same time.
The figure also shows the o/p wave from of 3 phase. Full wave form of voltage at anode D1,D2 & D3 while the curve 4,5, 6 shows the wave form of diodes D4,D5& D6 respectively.