Calibration of single phase energy meter by direct loading


To calibrate the energy meter by direct loading.


  1. Voltmeter
  2. Ammeter 
  3. Wattmeter
  4. Lamp load 
  5. Energy meter


The process of comparing of an instrument with standard or absolute instrument is called calibration. The energy meter records the energy consumed in KWH. Let RX be the number of revolutions of the disc. KX Is the revolution per KWH (meter constant). 


  1. Connections are made as per the circuit diagram 
  2. Keep the autotransformer at minimum position and switch on the supply 
  3. Adjust the autotransformer to the rated voltage of the energy meter
  4. Adjust the load to a suitable value and note the corresponding w/m reading and time taken for 5 revolution of energy meter disc 
  5. Repeat the step no 4 after increasing the load 
  6. Tabulate the readings and calculate the %error



Sl.Nov/m in VoltA/m in AmpsNo. of revolutionsw/m in WattsTime in secTrue EnergyActual Energy% error


Thus the given single phase energy meter is calibrated by direct loading.

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