[OpenTRV-dev] OT: Voltage drops

[Stuart Poulton]

Bo,

Can you clarify, are you talking about voltage and current measurement 
on a 3 phase supply ?

Thanks

Stuart


On 11/06/13 14:07, Bo Herrmannsen wrote:
> hmm... i think you are right.. its the phase shift part that will 
> benefit most from what i'm doing
>
>
> 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
>
> /bo
>
>
> 2013/6/11 Kevin Wood <EMAIL ADDRESS HIDDEN 
> <mailto:EMAIL ADDRESS HIDDEN>>
>
>     Indeed. Looking at the openenergy design, it's the current
>     monitoring side
>     that would be the largest source of error due to the fact that it
>     lacks
>     resolution, especially at low power levels. A couple of current ranges
>     rather than trying to do 0-100A in one range would help there (I think
>     someone's proposed a design to do just that somewhere).
>
>     Measuring mains voltage through an off-the-shelf step-down transformer
>     with a purely resistive load takes us back into the comfort zone
>     of most
>     constructors as far as safety goes and I can't believe it
>     introduces much
>     of an error if calibrated. Maybe a bit of phase shift and
>     flattening of
>     the top of the waveform if the transformer is a bit close to
>     saturation?..
>     Not sure. Will have to have a play with that.
>
>     Kevin
>
>     > I think the question here is what are the benefits of 'almost error
>     > free' mains voltage measurements ?
>     >
>     > Then compare to the risks, biggest being death, or fire.
>     >
>     > Stuart
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