Monitoring electricity consumption of a device?

Go to www.sensors.com and ask the same question.
You will almost certainly have to use a data collection system sampling at
a fairly high rate. I don't believe there exists any simple meter that will
integrate the usage, so you need the digital equivalent of a continuous
chart that will do the integration for you. Of course, the power company's
meter does that, if you want to spend the money and record the readings by
hand.

--
Mike Firth
No more levees
Bury old Orleans
Raise New Orleans up if it is worth saving
--
wrote in message
oups.com...
I'm building what I believe will be a super high efficiency electric
furnace utilizing engineering technology overlooked by studio glass
makers. But I need a method to prove my energy usage so I can present
my findings. Besides thorough documentation of my charge and idle
cycles, I need a meter that will work with a phase-angle SCR. I'm not
familiar with any device that can monitor my usage through an SCR. With
an inductive ammeter, one would need a constant graph since current
draw flucuates wildly from moment to moment. Any usenet folks out there
have any ideas?

So, does this overlooked technology make Ohm's law obsolete? Why can't you
calculate the energy usage? You know the resistance of the heating elements
and the amount of time you need to achieve the temperature rise in the
furnace and the line-in voltage. What else do you need?



wrote in message
oups.com...
I'm building what I believe will be a super high efficiency electric
furnace utilizing engineering technology overlooked by studio glass
makers. But I need a method to prove my energy usage so I can present
my findings. Besides thorough documentation of my charge and idle
cycles, I need a meter that will work with a phase-angle SCR. I'm not
familiar with any device that can monitor my usage through an SCR. With
an inductive ammeter, one would need a constant graph since current
draw flucuates wildly from moment to moment. Any usenet folks out there
have any ideas?

Moonraker wrote:

So, does this overlooked technology make Ohm's law obsolete? Why can't you
calculate the energy usage? You know the resistance of the heating elements
and the amount of time you need to achieve the temperature rise in the
furnace and the line-in voltage. What else do you need?


Ohm's law works fine but he's only firing at a fraction of the time once
he's up to temp. This varies by the surrounding conditions. A KWH meter
will tell the real story. My kiln draws 56A when it's on full bore, but
seldom is it doing that.

On most controllers we can see what percentage of full power is being
applied. He could see what percentage each furnace uses to maintain a
given temp (2100F?) at like ambient conditions.

--
Jack

Plonked by Native American

bobo1148atxmissiondotcom


http://photos.yahoo.com/bc/xmissionbobo/

A couple things: My controller is always set at 100% output signal;
it's the P.A. scr that varies the output. If you put an ammeter on it,
even while the furnace is at equilibrium and totally thermally stable
and idleing, the current jumps all over the place, and that's normal. I
do think a regular watt hour meter is what's required but like Mike
Firth says I'm not sure if I can get one that will work only on the
furnace circuit and also be compatible with the SCR. Yes of course the
power company meters the usage, and I'm certainly not trying to cheat
them. But it is noteworthy that at my other studio in Hawaii the meter
always had trouble and they never really figured it out.

Jack my house in Hawaii and coldwork shop is off the grid (solar and
bio-diesel) but my former hotshop over there never was. Here in Oregon
I have grid power. Also

The technology I'm using has to do with insulation, not the energy
input. The reason I need to monitor the power is that I don't believe
surface area and heat loss equations are going to provide a good real
world analysis. Plus, I suck at math. I have a way to vary these
insulation qualities while keeping the other parameters (mostly) the
same. So if I can accurately measure usage...

If your goal is to develop a kiln that holds the heat more efficiently,
I suspect you'll find only the hobbyists are interested. Production
kilnformers usually want kilns that lose heat faster. Many build kilns
with fibreboard instead of bricks for specifically that reason. The
objective is to get the heat out as quickly as is safely possible so
you can fire the kiln more frequently. Most existing glass kilns lose
heat too slowly. Why would somebody want one that's even slower? The
cost of electricity is too small to be of consequence. My calculations
are it's about 1% of the value of each load.

I'd be happy to pay for 10 times as much electricity if I could cool
the kiln twice as fast.

wrote in message
oups.com...

I'd be happy to pay for 10 times as much electricity if I could cool
the kiln twice as fast.

Ummmm....that's what fans are made for.

This is a glass furnace Dennis. Its a completely different animal than
a kiln. But, In a world of runaway fuel costs even kiln formers should
be looking at ways ways to increase efficiency. There are ways to
increase efficiency vastly in kilnforming. Heating up and cooling down
for a few pieces is why most kilnformers will never make it pay. And
beyond that you'll have to figure out the secret yourself.

By way of background, glass blowers are generally told that furnace
efficiency has a defined limit. You can only insulate so much, beyond
which you start progressing backward in efficiency, due to the
increased radiant surface area of the furnace.

I have always had a problem with that fatalism. It has seemed to me
very uninspired thinking. My new furnace takes advantage of technology
my brother (He's a phd in materials science) and I have discussed over
the years. It has to do with strategizing to limit both conductive and
radiant heat loss, and emmissivity of metal surfaces. Beyond that...

Also, I have been very interested in cogeneration from glass furnaces.
Some of our learned scholars in the glass world believe profit in this
regard violates the second law of thermodynamics; I plan to grow
lucious avocados in Oregon in January AND have a super efficient
furnace--which is proof enough for me. My new furnace will lend itself
to co-generation, when I have time to do it. Or when gas hits six bucks.

wrote:

If your goal is to develop a kiln that holds the heat more efficiently,
I suspect you'll find only the hobbyists are interested. Production
kilnformers usually want kilns that lose heat faster. Many build kilns
with fibreboard instead of bricks for specifically that reason. The
objective is to get the heat out as quickly as is safely possible so
you can fire the kiln more frequently. Most existing glass kilns lose
heat too slowly. Why would somebody want one that's even slower? The
cost of electricity is too small to be of consequence. My calculations
are it's about 1% of the value of each load.

I'd be happy to pay for 10 times as much electricity if I could cool
the kiln twice as fast.


How much would you pay for the kiln? I've thought of building one with
tubes that would use forced air during the cooling cycle. It wouldn't
add more than a few hundred dollars to a large(16 sqft bed)kiln.

--
Jack

Plonked by Native American

bobo1148atxmissiondotcom


http://photos.yahoo.com/bc/xmissionbobo/

Moonraker
Only part of each cycle is being used in a phase shift SCR controller.
http://users.ticnet.com/mikefirth/control.htm#PHASE
If he were using zero crossing trigger SCR or SSR, and they were fired not
very often, then simply adding a small analog clock to the circuit would let
your method work- the number of minutes the clock was on gives a good idea
of the actual power used (% of day) [or a digital timer with electronic
on-off. I have analog, I don't own a digital timer.]

Jfuse
If you are interested in the details, you are going to need to do data
collection on a millisecond by millisecond basis, which is considered slow
in the Sensors world. And you are going to want to feed it into a file so
it can be loaded into Excel for averaging, totalling and graphing.
However, I do not follow what you say about your controller being at 100%
output. Something has to be controlling the Phase Angle SCR and that is
usually called a controller.

--
Mike Firth
No more levees
Bury old Orleans
Raise New Orleans up if it is worth saving
--
"Moonraker" wrote in message
...
So, does this overlooked technology make Ohm's law obsolete? Why can't
you
calculate the energy usage? You know the resistance of the heating
elements
and the amount of time you need to achieve the temperature rise in the
furnace and the line-in voltage. What else do you need?



wrote in message
oups.com...
I'm building what I believe will be a super high efficiency electric
furnace utilizing engineering technology overlooked by studio glass
makers. But I need a method to prove my energy usage so I can present
my findings. Besides thorough documentation of my charge and idle
cycles, I need a meter that will work with a phase-angle SCR. I'm not
familiar with any device that can monitor my usage through an SCR. With
an inductive ammeter, one would need a constant graph since current
draw flucuates wildly from moment to moment. Any usenet folks out there
have any ideas?

Hi Mike. As Jack pointed out, many of us have controllers that are
sophisticated enough to allow percentage-wise control of the output
signal. This can be used for various purposes, notably in our case, to
reduce watt-loading of elements. For example if your heater draws 60a,
you might set your output signal at 50% so that the elements are not
taxed at their maximum. Simply, a way of current limiting from the
controller. I don't use that feature however, because my scr has a
built in current limiter that can be set.

The analog clock will work with a mechanical relay or a mercury relay.
I would be very skeptical about it working with a burst-fire ssr under
any circumstances, but wtfdik.

I really have to avoid a very complicated system, Mike. If it is as you
say, and a particular type of current meter won't work, I'll just run
the furnace and know it is very efficient but not quantifiable.
Because, I don't build furnaces for a living, and I'm not writing a
dissertation. I have to make glass for a living.