CHECKING ACCURACY OF ELECTRIC METER

DanGacek

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Jul 25, 1997, 3:00:00 AM7/25/97

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If you think there might be some error call your local utility. They
should be able to tell you the last time that your meter was tested. They
should test the meter for you if you so request. It may take a few call
so that they know that you have a serious concern.

T, Patrick Culp

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Jul 25, 1997, 3:00:00 AM7/25/97

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This is a multi-part message in MIME format.
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The home electric meter is a time based current meter. i.e.. a
current-time integrator.
To check the meter for accuracy, a 60 hz. sine wave loaded to a known
current flow for a
specific time is applied against the meter. The longer the test the
more accurate it will
become. You can simulate the test by allowing a known current draw from
a high current
appliance to operate for a fixed time usually in some full hour
increments. The formula,
Power = Current * Voltage ( P=I*E ) per hour should give you enough
information to
guestimate the accuracy. Other useful formulas are...
E2= R*P
P= I2*R
P=I*E
P= Power or Watts
E=Voltage
I=Current
R=Resistance or Impedance.
P is sometimes called VA (volt amps) (( EI ))
* means multiply
For a complete description check out site...

http://www.avointl.com/kwhmetr&.html

You probably know most of this but I thought I should state it anyway.
Hope this helps a little.
TPC
http//www.pinnacleweb.com

Andrew Auletta wrote:

> Charlie --
>
> As I said in my email response, I need to know how to do it myself so
> that I can do it, or explain the process to my clients if possible.
>
> Anyone know the process?

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<HTML>
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The home electric meter is a time based current meter. i.e.. a current-time
integrator.
 To check the meter for accuracy, a 60 hz. sine wave loaded to a known
current flow for a
 specific time is applied against the meter.  The longer the test
the more accurate it will
 become.  You can simulate the test by allowing a known current
draw from a high current
 appliance to operate for a fixed time usually in some full hour increments. 
The formula,
 Power  = Current * Voltage ( P=I*E ) per hour should give you
enough information to
 guestimate the accuracy.  Other useful formulas are...
 E2= R*P
 P= I2*R
 P=I*E
 P= Power or Watts
 E=Voltage
 I=Current
 R=Resistance or Impedance.
 P is sometimes called VA (volt amps) (( EI ))
 * means multiply
 For a complete description check out site...
<UL><A HREF="http://www.avointl.com/kwhmetr">http://www.avointl.com/kwhmetr</A>&.html</UL>
You probably know most of this but I thought I should state it anyway.
 Hope this helps a little.
 TPC
 http//www.pinnacleweb.com

Andrew Auletta wrote:
<BLOCKQUOTE TYPE=CITE>Charlie --

As I said in my email response, I need to know how to do it myself so
 that I can do it, or explain the process to my clients if possible.

Anyone know the process?</BLOCKQUOTE>
 
  
  
</BODY>
</HTML>

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Henry F. (Hank) McCall

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Jul 25, 1997, 3:00:00 AM7/25/97

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Charles L. Perrin wrote:

>
> Aul...@pluto.njcc.com (Andrew Auletta) wrote:
>
> >As I said in my email response, I need to know how to do it
> >myself so that I can do it, or explain the process to my
> >clients if possible.
>

> I did some searching on the subject and found some information about
> how it's done. Take a look at:
>
> http://www.avointl.com/kwhmetr&.html
>
> Basically, they test it at full-load and 10% of load and verify that
> the spinning disk rotates at the correct speed. (It takes some
> specialized test equipment--or it's easiest to do it with such!)
>
> --------------------------------------------------------------
> Charlie's Sneaker Pages: http://sneakers.pair.com/
> Best Value in Airplanes: http://www.boeing.com/
> --------------------------------------------------------------
Ther is a little black spot on the diameter of the spinning disc. This
makes it easier to count revolutions. Since it typically takes FOREVER
to get a meaningful dial indicator reading, this is an alternative.
There is an indicator on the model number tag that tells how many
revolutions equals one watt-hour. In order to test, you will have to
know that number (call the utility?) make sure there are no cyclic loads
in operation. measure the time to indicate some number of watt-hours.
dividing thewatt-hours by time in hours gives watts. Add a noticeable
non-cycling load and repeat. The difference in watts should be equal to
the added load. Obviously, greatest accuracy is achieved if all house
power is shut down except for the known load. The closer to this
extreme, the better. Also remember that at some times of the day,voltage
varies a lot, so don't use nominal voltage to calculate power. You might
even want a voltage chart recorder at the load.
--

It is better to keep one's mouth closed and be thought a fool,
than to open it and remove all doubt. Abraham Lincoln
I really have to start listening to Abe. ;>)

Hank McCall

Grant Killen

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Jul 28, 1997, 3:00:00 AM7/28/97

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Aul...@pluto.njcc.com (Andrew Auletta) wrote:

>Charlie --

>As I said in my email response, I need to know how to do it myself so
>that I can do it, or explain the process to my clients if possible.

>Anyone know the process?
In the old days (1976 say) the ideal was to take a thing called a
rotating standard ( or a very acurate meter that is used to calibrate
other meters), connect it and the meter under test to the same load,
(switchable power factor and load level) and operate the testing meter
for a period of time (60 seconds rings a bell, but it could also be an
echo from that hole within my head) you then compare both readings.
They should be within the tolerance of the meter. Old meters are
usually slow NOT fast as the pivots wear. Very few are fast but it
occasionally does happen. Regards, Grant