meter disc revolution

[Eric Lindholm]

I'm trying to track down why our bills are so high, and I have several
appliances of unknown wattage. So I figured I'd turn them on and off and
make calculations using the speed of the meter disc, the thing with the
little black wedge painted on it.

What amount of power usage does one revolution of this disc indicate? I
called Southern California Edison and was given two answers: 1 kWh (way too
high) and then, after I asked for an "expert," 1 kW (wrong unit).
Eyeballing it, I'm guessing it might be 10 Wh, but can someone tell me for
sure?

Thanks in advance.

 

[Eric Lindholm]

Count how many times the disk goes around to make the last dial on the

meter increment by one. the last dial is usually 1KWH. You can verify
that by looking at the readings on your bill. So divide 1 KWH by
however many revolutions and you'll get the number you are seeking.

Yeah, I didn't really want to stand there all day...

 

[Eric Lindholm]

Thanks for the responses. A code on the meter says "CL200," so maybe that's
the 200 rev/kWh, although a quick internet search seems to suggest that it's
only a model number. Nothing else in the string of code seems applicable.

My main concern is out air-conditioning fan. We live in a dustbin and I
installed a whole-house air cleaner. It seems to help, but "for optimal
performance," were supposed to keep the fan running all the time. Our
compressor is ancient and I can't find any useful information on it, so I
have no idea what power the fan itself (with no A/C or heat) draws. I want
to be able to say, "This fan is costing us X dollars per day to run," so
that's why I need an absolute number. If I know the revolution measure,
it's a trvial matter to measure the speed with the fan on or off and
calculate the difference.

 

[Eric Lindholm]

By the time you found the phone number and called So Cal Ed, waited on

hold, asked two people, eyeballed your meter, and composed a post to
usenet, you spent more time than you would have in front of the meter.
But hey, you got to see just how "expert" some experts are.

Right now it's making a revolution about every 10 seconds. If it's true
that it's 200 revs per kWh, I'd be out there for more than half an hour,
standing and watching the thing.

If you don't know the answer, don't post.

 

[Eric Lindholm]

Or, I might power on one appliance with a fixed load, like... oh, I

dunno... a 1,000 watt space heater?, time the number of revolutions
per minute, and extrapolate the number, then come back in an hour and
see if I was right. But then, I'm not an expert, and I probably
shouldn't post. Friggin lazy sod.

Thanks for your help. I'll instruct everyone else in the household not to
turn anything on or off for an hour, so that I can conduct your experiment.
I'll also unplug our refrigerator, since I can't control its behavior.

In case it's not clear, I know perfectly well how to establish the answer
emperically. I thought posting here would be faster, since surely it's a
piece of information many people have at their fingertips. Obviously I was
wrong.

 

[Eric Lindholm]

Poor baby. In case you missed that class, a refrigerator can go for

more than an hour without power and still not spoil food. And last
time I checked, when you threw the breakers, turning switches on or
off had no effect on power usage.

Jesus. I know how to disconnect power to my refrigerator.

What is clear is that you can't control your own life for an hour, and
you want easy answers, and you can't handle it when people suggest you
can find them on your own with a little thought.

You crack me up. I'll bet if you're in a room with several people, wearing
a watch, and someone calls out "Does anyone know what time it is?" you
snarl, "Figure it out yourself, you lazy sod."

The point of usenet is to share information, not to put people down for
trying to save time by asking for quicker answers. It should have been
clear from my original post that I wasn't intimidated by the arithmetic
involved. You told me something I already knew, then got angry when I
pointed out that it didn't answer my question. Why you chose to respond in
the first place is a mystery.

The reason that I suggested an empirical validation is that meters can
be different, or even read incorrectly.

And empicial measurements are susceptible to measuring error. In the time
between posts, I have made several measurements -- since it was apparent
here that no one was going to give me a simple answer -- and they've varied
by about 15%. Please don't lecture me about how that means I need to take
larger samples.

Just to humor you, and give you the type of answer you wanted, look
for the meter constant on the face of the meter. It'l be Kh followed
by a number, such as Kh6. Mathematically the power usage is found by:

Power(in watts) = (revolutions of disk/minute) x 60 minutes x Kh

Thanks. It says Kh7.2. As you point out later, your equation simplifies to

Energy consumption (in watt-hours) = revolutions x Kh

or 1 revolution = 7.2 W-hr, which is all I wanted.

By the way, there's no way I would have gotten a measurement accurate to two
digits through testing, short of spending all day on it. There are just too
many uncertainties. A 1000-W appliance doesn't draw exactly 1000 W every
instant it's on. Also, since an earlier post suggested that the answer
might be 5 (which my tests indicated was probably too low), it wouldn't have
occurred to me that it wouldn't be an integer.

I'm not sure why you decided to answer the question now after spending your
first few posts insulting me instead, but I'm glad that you did. Thank you
for taking the time.

 

[William P.N. Smith]

What amount of power usage does one revolution of this disc indicate?

As others have pointed out, it can vary a bit. I've got a couple of
7.2 watt-hour per revolution meters here, and IIRC my new one is
10wh/rev.

You really need a clamp-on ammeter and a Watts-Up to make sense of
readings, watching the meter go around is really going to waste your
time...

 

[Eric Lindholm]

I'll venture a guess -- about 500 watts, or a buck a day in round numbers.

Heh, you could have saved me a bunch of time. That's about what I've come
up with, after all of this hassle.

Our round-the-clock average usage is about 1700 W, so the fan is a big
culprit, but it seems like we have to be able to make other cutbacks
somewhere -- it's not that big a house, and this is in a period with no
climate control costs. Time to get a lot more diligent about turning lights
off.

 

[William P.N. Smith]

A clamp meter is a handy thing to have around but not for measuring
the cost of operation.

Agreed. However, if you want to get a quick handle on where your
power is going, a clamp-on ammeter will at least tell you where your
current is going, and give you a first-approximation of loads active
in your house.

I should have suggested a clamp-on ammeter _and_ a Watts Up Pro for
measuring both gross current consumption and individual appliance
operating costs. Oh, wait, I did.

 

[daestrom]

I'm trying to track down why our bills are so high, and I have several
appliances of unknown wattage. So I figured I'd turn them on and off and
make calculations using the speed of the meter disc, the thing with the
little black wedge painted on it.

What amount of power usage does one revolution of this disc indicate? I
called Southern California Edison and was given two answers: 1 kWh (way
too high) and then, after I asked for an "expert," 1 kW (wrong unit).
Eyeballing it, I'm guessing it might be 10 Wh, but can someone tell me for
sure?

The answer is on the face of the meter. It just isn't easy to recognise.
Almost all meters for home use have a number called Kh listed on the meter
face. A very common value is 7.2. That is 7.2 watt-hours per disc
revolution.

daestrom

 

[[email protected]]

Oh...Harry . You make it too simple for him....let this lazy ass figure out
this by himself...

 

[wmbjk]

You truly are an idiot.

Practice makes perfect...

Google Neon John to get a sample of his
knowledge in areas like this.

And for comparison, Google some of the Solar Faker's previous nyms
such as "Gymmy Bob" and "John P Bengi" to sample his lack of knowledge
on pretty much any subject. See what I mean about practice?

Time for you to go bye-bye.

You'll miss some top-notch nitwittedness.

Wayne

 

[daestrom]

NO.

GE electronic types (CL200 he told us) is marked "Kt" and not "Kh"

Kh was only used for mechanical disk meters.

The OP *quite clearly* asked about, "...So I figured I'd turn them on and
off and make calculations using the speed of the meter disc, the thing with
the little black wedge painted on it."

Do you know of an electronic meter that has a 'meter disc'?? With a 'black
wedge painted on it'??

As someone else pointed out, CL200 is the meter class, not necessarily the
construction.

daestrom

 

[JoeSP]

I'm trying to track down why our bills are so high, and I have several
appliances of unknown wattage. So I figured I'd turn them on and off and
make calculations using the speed of the meter disc, the thing with the
little black wedge painted on it.

What amount of power usage does one revolution of this disc indicate? I
called Southern California Edison and was given two answers: 1 kWh (way
too high) and then, after I asked for an "expert," 1 kW (wrong unit).
Eyeballing it, I'm guessing it might be 10 Wh, but can someone tell me for
sure?

Thanks in advance.

If you're trying to track down why your bills are so high, finding a fault
with the meter is the least likely possibility. Check all your automatic
devices to see if they're running continuously; well pumps, sewage pumps
electric heaters etc. If that fails, use an ammeter to test all your
circuits and see if they match the rated consumption specs. If that fails
look for something like an underground short.