Measurement of techniques used in the study of variable speed drives

The popularity of AC variable speed drives is increasing very rapidly. Measurement techniques that are used to investigate sinusoidally supplied motors are not always satisfactory-many instruments do not have the necessary frequency range to measure parameters such as voltage, current and power accurately. There is often a need to correlate many different parameters, for example to investigate the effect that the output waveforms of various different types of convertors have on noise and vibration. In many cases, particularly when measurements have to be made on site, there is limited time and access available for testing. Understanding is also helped by presenting the data in a clear and readable form. Signal conditioning, recording and signal processing equipment is described which enables signals to be recorded onto multichannel instrumentation tape recorders for later analysis