07/04/2017

Working of Six Phase Half Wave Uncontrolled Rectifier


  • The connection diagram for six phase half wave uncontrolled rectifier is shown in the figure A. 
  • The primary winding of the transformer is connected in delta whereas the secondary winding consists of center taped star winding. 
  • The point N is common point at which the center tap of each winding is connected. 
  • The voltage across R phase, Y phase and B phase are 120o phase displacement with each other whereas the voltage across R and R’, Y and Y’ and B and B’ is 180o.


six-phase-half-wave-uncontrolled rectifier.png


         










Working
  • The waveform of the six phase and conduction of diodes are shown in the figure B.

Point a 

  • The voltage of the phase Y’ becomes maximum with respect to other phases therefore the diode D6 conducts and current flows through path phase Y’ – D6 – Load – N.

Point B 

  • The voltage of the phase R becomes maximum with respect to other phases therefore the diode D1 conducts and current flows through path phase R – D1 – Load – N.

Point C 

  • The voltage of the phase B’ becomes maximum with respect to other phases therefore the diode D2 conducts and current flows through path phase B’ – D2 – Load – N. 
  • Similarly the diode D3, D4 and D5 conducts for specific time interval.

six-phase-half-wave-uncontrolled rectifier-waveform.png














Features

  • Each diode conducts only for positive half cycle.
  • Each diode conducts for 60o duration
  • Low ripple factor
  • The average DC output voltage and current suppy to the load is higher than that of three phase half wave rectifier.
  • The zig – zag connection in the secondary of the transformer is used in order to reduce DC saturation of the core.

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