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[on:]

I'm researching a home power meter project, and despite all that I've read on Open Energy Monitor [http://openenergymonitor.org/emon/] and a nice if difficult-to-read Instructable [http://www.instructables.com/id/Make-a-Rogowski-coil/], I haven't seen anybody put Rogowski coils forward as a viable alternative to other current sensors. For my version of the power meter, I'm planning on using the Analog Devices ADE7753, which has the integrator on the current input that would be necessary to get the correct value from the Rogowski coil, perhaps it's that folks are looking to use a simpler (if ultimately more expensive) way to measure current directly with an Arduino.

So, the question is: is anybody else using Rogowski coils for current sensing? Are they DIY or purchased? Opinions about accuracy, efficacy, etc.?

Cheers,

--R

[Reply #1 on:]

It don't think it will be sensitive enough at low frequencies (50/60Hz), there's nowhere near enough mutual inductance compared to using a magnetic-cored transformer.  Try winding the coil on a ferrite toroid.

[Reply #2 on:]

Yeah, my reading was sending me to that conclusion as well. I would need to wind this thing umpteen thousand times with 60 AWG magnet wire in order to be sensitive enough at low amplitude. Wrapping it around a ferrite core was what I was trying to avoid, since I wanted to wrap it around both legs of my home's split-phase 240V mains conductors at the same time.

I was also drawn in by the attractiveness of the air core, I admit it.

I may still give it a try, but I'm considerably less excited about Rogowski coils now. bummer. 

[Reply #3 on:]

Rogowski's are used routinely by power co's - operating at 60Hz in North America.
I am trying to use one fed directly to the adc; the coil produces a derivative of the
current; for a sine wave that's a cosine wave. Looks the same, 90⁰ out of phase.
Just having trouble getting the spec - it produces ".404 mV/A" which is a useless fact because
that can be peak volts, peak-to-peak or rms.

[Reply #4 on:]

I am trying to use one fed directly to the adc; the coil produces a derivative of the
current; for a sine wave that's a cosine wave.

Does being 90º out-of-phase bother you in terms of reading the value directly into the ADC?

Just having trouble getting the spec - it produces ".404 mV/A" which is a useless fact because
that can be peak volts, peak-to-peak or rms.

My guess would be that any AC-related voltage spec (which a CT or Rogowski would be) would be given as RMS. But a voltmeter should be able to ascertain the reality for you.