Question

A dynamometer instrument is mainly used as
1. dc ammeter
2. wattmeter
3. dc voltmeter
4. ohmmeter

Answer 1

Correct Answer - Option 2 : wattmeter

• As the dynamometer instrument has Square Law response so can be used on both the DC as well as on AC.
• It is mainly used to measure both AC and DC power. Hence, used as a wattmeter. 
• These instruments are free from hysteresis and Eddy current errors. It is because of the absence of iron in the operating part of the instrument.
• Ammeter up to 10A and voltmeter up to 600V can be constructed with precision grade accuracy.
• Dynamo type voltmeter is useful for accurate measurement of RMS value of voltage irrespective of the waveform.
• Because of Precision grade accuracy and the same calibration for DC and AC measurement instruments are used as transfer and calibration instruments.