G SEVEN wrote:
>
> These are the following meters with associated shunts I am looking for.
>
> filament voltage - 10 VAC
> filament current - 200 amps
> plate voltage - 10 KV
> plate current - 10 amps
> supply voltage - 220 VAC
> supply current - 200 amps
> grid current
> forward watt meter
> reverse watt meter
>
> I want alll meters to be of the same maker for the exception of the Bird
> watt meters.
I would have thought you have been quite lucky to get all those meters
matching. In contrast, buying 9 x 1 mA meters and making your own shunts
and multipliers should not be too difficult. The value of the 200 A
shunts is not critical, as you can trim them. The AC ones will require
rectification, but that is not difficult to do. It does mean the scales
will be non-linear at the bottom end, but that should be no problem. In
fact, given they are mains and heater voltage, which you would not
expect to differ more than say 20% even on a poor generator from the
nominal values, I'd be tempted to use a zener diode in there and produce
a scale that does not start at zero.
I've done this sort of thing with cheap surplus meters. You can make
your own scales, which will for power be non-linear. You can put them
into colour coded regions - red for danger, yellow for caution, green
for fine. If you print the scales on an inkjet printer, the results look
quite good. I've learnt from experience if you do this, you should use
good quality inkjet paper, as otherwise they can bleed over time.
Here are a few of my meters that I pulled from the shed a few mins ago.
I will fit these in a couple of amps (Y799 and YC156) when I get time to
finish them. These have been in one of my sheds for at least 3 years.
Kept in the dry, and with decent paper for the scale, you should have no
problems like you see on one or two of those.
http://www.david-kirkby.co.uk/meters2.jpg
I assume you know how to design shunts/multipliers, but if not, I'm sure
any book will tell you.
--
Dr. David Kirkby Ph.D,
email: drkirkby@ntlwold.com (formally davek@medphys.ucl.ac.uk)
web page: http://www.david-kirkby.co.uk
Amateur radio callsign: G8WRB
--
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