Which of the following systems would be most likely to produce a power waveform that would require a true RMS meter to accurately measure?
A. A shaded-pole motor controlled by a relay
B. An electric strip heater controlled by a contactor
C. A three-phase motor controlled by a variable-frequency drive
D. An incandescent light controlled by a toggle switch
Answer (2)
The most accurate option is C, as a three-phase motor controlled by a variable-frequency drive produces a complex waveform that requires true RMS measurement. Other options generally operate with simple sinusoidal waveforms, suitable for standard measurements. True RMS meters are vital for ensuring precision in non-sinusoidal applications.
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The correct answer is C, a three-phase motor controlled by a variable-frequency drive, as this system produces a complex waveform that requires a true RMS meter for accurate measurement. Other options typically produce sinusoidal waveforms suitable for standard meters. Hence, the true RMS meter is crucial for non-sinusoidal applications. ;
