Re: gEDA-user: Transformer as voltage transducer?

["John Luciani" <jluciani@xxxxxxxxx>]

On 5/25/07, Randall Nortman <geda-lists@xxxxxxxxxxxxxxx> wrote:
> I would like to measure mains voltage (110-240V, 60Hz), but I want my
> measurement circuit to be isolated from the voltage being measured.  I
> am going to be sampling the waveform at a high sample rate (relative
> to the 60Hz waveform being measured) and comparing that with the
> current on the same lines with (near-)simultaneous measurement.  So it
> is important to me that the voltage waveform not be distorted or
> phase-shifted, and the voltage I see should be related to the source
> voltage by a simple linear ratio.
>
> Seems like a simple transformer will do it, in theory.  But I'm not
> sure about how they will work in the real world.  Do transformers
> distort the voltage waveform or phase?  What happens if I put a load
> on the secondary of more than a few nA?  What non-linearities are
> there?  What sort of transformers are going to give me the best
> response?

There was a Watt-Hour Meter article in the April 2002 issue of Poptronics.
The voltage measurement transformer was a Tamura 3FD-216. For current
measurement a Coilcraft CS2106 transformer was used.

(* jcl *)

-- 
http://www.luciani.org


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