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Re: New wattmeter
Tesla List wrote:
>
> Original Poster: David Euans <davide-at-mailhost.accesscom-dot-net>
>
> Just wanted to let everyone on the list know about a Simpson analog
> wattmeter we recently installed on our power supply. It is a 4.5 inch
> meter - wide-vue style, model 1379, catalog # 11000. It is said to
> correct for phase differences as we might find in our coil systems. The
> original meter has a 0-1500 watt range. We used a 50:5 current
> transformer to increase the range to 15 kw. We also used custom 0 - 15
> kilowatt scale. On a recent run our output meters read 35 amps at 270
> volts. The meter gave a reading of 7.2 kw. I suspect that this might
> be a more accurate measure of our output. Comments are welcome.
One minor comment. One of the differences between expensive and
cheap current transformers is how little phase shift they
introduce. Cheap ones can have significant phase shift. Any phase
shift will appear as false power factor.
If you want to measure power in our range of interest directly, get
a utility-type watt-hour meter. I see them surplus all the time
from electronic surplus dealers such as C&H Sales all the time in
the $35 range, usually with a meter base included. The register
(dials) record watt-hours but you can measure watts by timing how
fast the wheel turns. The Kh factor on the dial face is how many
watt-hours one revolution of the wheel is worth.
John
--
John De Armond
johngd-at-bellsouth-dot-net
Neon John's Custom Neon
"Bendin' Glass 'n Passin' Gas"