Transformer Utilization Factor (TUF) of single phase half wave rectifier

Transformer Utilization Factor (TUF)While designing any power supply, it is necessary to determine the rating or the transformer. It can be done provided TUF is known. The value of TUF depends on the amount of power to be delivered to the load and the type of rectifier circuit to be used.

TUF = dc power delivered to the load /ac rating of transformer secondary


= Pdc/Pin.rated

At first sight it might appear as if the above ratio is the same as the conversion efficiency. Actually, it is not so because the rating of the transformer secondary is different from the actual power delivered by the secondary.

Pdc = VL(dc).IL(dc)

= VLM/π . VLM/RL

= VLM2 /πRL

= Vsm2 /πRL     - if drop over R0 is neglected

Now, the rated voltage of transformer secondary is Vsm/√2 but actual current flowing through the secondary is IL = ILM/2 (and not ILM /√2) since it is a Half-Wave rectifier current.

Pac.rated = Vsm/√2 .ILM/2

= Vsm/√2 . VLM/2RL

= Vsm/2√2RL

TUF = (Vsm 2/πRL)/(Vsm2/2√2RL)

= 2√2/π

= 0.287

However, due to saturation effects produced by the flow of direct current through the transformer secondary, the value of TUF is further reduce to 0.2.

Obviously, dc power deliver to the load = ac transformer rating × TUF




Related Topic 

  1. Single-phase half-wave rectifier
  3. Efficiency of single-phase half-wave rectifier
  4. Frequency Component of Half-Wave Rectifier Voltage and Current
  5. Ripple Factor of single phase Half-Wave rectifier
  6. Peak Inverse Voltage (PIV) of single phase half wave rectifier
  7. Peak current of single phase half wave rectifier
  8. Advantage and Disadvantage of single-phase half-wave rectifier

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