Measurement of Input Power of DC Motors Operated Using Rectifier Power Supplies and Choppers

The significance of measurements of the ac and dc components of input power of shunt-and series-wound dc motors operated from rectifiers is presented. Suggestions are given to check and improve the degree of accuracy of power measurements using conventional moving-coil wattmeters. A newly developed electronic wattmeter is described which has been found to provide improved accuracy in rectifier applications. Test results are presented.