Understanding RMS Voltage & Current in Automotive Systems #
Ever wondered how to get the true value of an AC signal? The answer is RMS. While a simple peak-to-peak measurement can be misleading, the RMS value gives you a definitive, consistent measurement of a waveform’s voltage or current. This is essential for accurately analyzing everything from alternator outputs to 3-phase electric motors.
The power of maths certainly adds a new dimension to post-capture analysis, and I’d like to thank you for following this article series.
I would like to include two additional forum posts here that I find helpful when examining RMS values of AC signals.
While the Math can be challenging, once you have the math channel loaded into your library, it will always be there, ready for use.
The first post looks at graphing the RMS voltage of an AC Signal.
To calculate the RMS voltage of a single AC Signal: sqrt(integral((A)^2)/T)
The following .psdata file contains the math channel above:
The second post looks at graphing the RMS current of a 3-phase electric motor under acceleration from rest.
To calculate the RMS current, we use the following math channel formula:
sqrt(integral(A^2)/T)+sqrt(integral(B^2)/T)+sqrt(integral(C^2)/T)
The following .psdata file contains the math channel above.