RMS measurement vs window size and waveform phase offset.

Sample Windows in Asynchronous Efficiency Measurements

In modern power systems, analysis often requires the efficiency measurement between two
asynchronous, periodic waveforms. For example, a variable-frequency drive with mains input generates a secondary AC output with selectable frequency for controlling the speed of an AC motor.

To establish system efficiency, both swiftly and accurately, the input and output waveforms need to be identified in the correct sampling window.

Despite this, synchronising each waveform independently is not typical. You will learn why minimising error in efficiency measurements for power analysers and data acquisition systems, plus why it is important to establish independent frequency detection and associated windows when measuring asynchronous waveforms.

In the whitepaper Sample Windows in Asynchronous Efficiency MeasurementsNewtons 4th (N4L) analyse:

  • Sample window size, measurement error and the limitations of using a finite window to measure a Root Mean Square (RMS).
  • Strategies for minimising sine wave form errors.
  • Extending “windowing” to an efficiency measurement in
    asynchronous systems.

Tackling the common assumption that the optimum efficiency of an electrical system is an analysis of results taken at the same time, N4L look at correct frequency synchronisation and establishing a measurement window. The result is quicker and more accurate efficiency measurement for electrical engineers. Read the whitepaper Sample Windows in Asynchronous Efficiency Measurements. [1,663k PDF]


Caltest Instruments Ltd.Establishing the right measurement window yields speedier and more accurate efficiency measurements.

Caltest Instruments are experts in the field of power instrumentation. Call us on 01483 302 700 and speak with our experts to create a system that’s ideal for your power project.