Power transformers are designed to have maximum efficiency at

A. nearly full load
B. 70% full load
C. 50% full load
D. no load

Answer: A

Explanation:
  • Power transformers have maximum efficiency at full load. Power transformers are intended to be as efficient as possible under full load since they are used at full load. The transformer's output power is 0 when the load is not connected across the transformer's secondary. Power transformers step up or down the applied input power (Voltage). The efficiency of the power transformer is always greater than 90%. So it is considered a highly efficient electrical device.
  • From many experiments, power transformers perform with maximum efficiency at full load. When the load increases, then the output of the power transformer also increases. When the bag is null, the output power will be zero.
Facts About Power Transformers:
  • Power transformer efficiency is the ratio of output power to input power.
  • When the load is low, the power transformer experiences hysteresis and eddy current loss. So the efficiency of the power transformer became less.
  • When the load of the transformer increases, then the efficiency increases. Both are directly proportional to each other.
  • When the load of the power transformer is zero, then the output voltage is zero, and efficiency also becomes zero.
  • The efficiency of transformer= V1/V2=P1/P2=I2/I1.
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