yep, 3phase is standard here (almost) 3phases+neutral+earth<br><br><div class="gmail_quote">2013/6/11 Stuart Poulton <span dir="ltr"><<a href="mailto:stuart@poulton.org.uk" target="_blank">stuart@poulton.org.uk</a>></span><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Bo,<br>
<br>
Can you clarify, are you talking about voltage and current measurement on a 3 phase supply ?<br>
<br>
Thanks<br>
<br>
Stuart<br>
<br>
<br>
On 11/06/13 14:07, Bo Herrmannsen wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
hmm... i think you are right.. its the phase shift part that will benefit most from what i'm doing<br>
<br>
<br>
i will also agree to that 0-100A is rather a hughe step... for me thats far beyound what i need, i can draw a max of 16A amps on each of the 3phases i got in the fuse box<br>
<br>
/bo<br>
<br>
<br>
2013/6/11 Kevin Wood <<a href="mailto:kevin@the-wood-family.com" target="_blank">kevin@the-wood-family.com</a> <mailto:<a href="mailto:kevin@the-wood-family.com" target="_blank">kevin@the-wood-family.<u></u>com</a>>><br>
<br>
Indeed. Looking at the openenergy design, it's the current<br>
monitoring side<br>
that would be the largest source of error due to the fact that it<br>
lacks<br>
resolution, especially at low power levels. A couple of current ranges<br>
rather than trying to do 0-100A in one range would help there (I think<br>
someone's proposed a design to do just that somewhere).<br>
<br>
Measuring mains voltage through an off-the-shelf step-down transformer<br>
with a purely resistive load takes us back into the comfort zone<br>
of most<br>
constructors as far as safety goes and I can't believe it<br>
introduces much<br>
of an error if calibrated. Maybe a bit of phase shift and<br>
flattening of<br>
the top of the waveform if the transformer is a bit close to<br>
saturation?..<br>
Not sure. Will have to have a play with that.<br>
<br>
Kevin<br>
<br>
> I think the question here is what are the benefits of 'almost error<br>
> free' mains voltage measurements ?<br>
><br>
> Then compare to the risks, biggest being death, or fire.<br>
><br>
> Stuart<br>
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