Re: Core imbalance in RCDs

Tony Williams wrote:

> > If I had my electronics stuff around I would take a toroid
> > transformer, put an AC voltmeter on the coil with most turns, to
> > make it easier to measure the induced voltage. (maybe an amp
> > before the voltmeter)
>
> > Then I would send an AC signal through a wire and hold it close
> > to the core, see its response, start shaping it around the core,
> > 1/4 of a turn, half a turn, 3/4 of a turn, and see if the voltage
> > goes up gradually as the wire is shaped better and better around
> > the toroid core, but without going through it.


> 1. |
> | ____________
> || |---
> 1A || Toroid | 35mV
> ||____________|---
> |
> \|/
>
> 2.
> ____________
> | |---
> | Toroid | 0mV
> |____________|---
> 1A----------------------->
>
> /
> 3. /
> /____________
> || |---
> 1A || Toroid | 50mV
> ||____________|---
> \
> \
> \
>
> 4. __________________
> | ____________
> || |---
> 1A || Toroid | 34mV
> ||____________|---
> |__________________
>
>
> :-)
>
> Bit rough and ready. I'll do it more carefully
> some time later today, to confirm (or not).

Nice pictures.

The first picture shows a 1/3 turn, as the wire goes straight
tangentially on the outside, result 35mV.

Picture 2, the effects on both sides cancel each other, zero result.

Picture 3, bending the wire shapes it better around the outside,
stronger signal, we could call it 1/3 turn plus a little more, =0.4
turns.

Picture 4, the wire influences the opposite side of the toroid so it
cancels some of the influence on the other side.

We could also put the wire through the core once, to see how much
stronger the influence gets, to compare the result with the fractional
turns experiments.


--
Roger J.
.

Relevant Pages

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  • Re: Core imbalance in RCDs
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