Craig Clark on fri 6 oct 06
Alyssa, just to add to what Maurice is describing, to help you
further understand things........go outside of your studio/home and look
for the place that the wires from the power pole run into your power
panel. This is called the weather head. There are three wires. Two of
the wires are what are commonly called "hot" wires. Each of them has a
voltage potential (energy), in ideal situations, of 120 volts AC. The
third wire is the called the "common" wire. It does not, for practical
purposes, carry voltage, at least if there is not a problem. It is
connected to what is called the "center tap" on the transformer at the pole.
A basic understanding of the electricity that travels through the
two hot wires, which in turn powers your kiln and every other electrical
item in your studio will help you to understand and solve your problem.
The information will help you know if the electrician or power company
representative is giving you good/honest information of not.
A common analogy of an electric system, which helps folks understand
what is going on, is by comparing an electrical system to a plumbing
system, as in a system of pipes filled with water. I am giving you a
synopsis of the link to follow to a site which explains this very well
and in more detail. The voltage can be understood by thinking of it as
the pressure of the system. Just like the amount of pressure that the
water in a particular plumbing system has. The amount of electricity
that flows through the system may be looked at as the volume of water
that is flowing through the plumbing system. This is what is called
current, and it is measured in amperes......amps.
Keep in mind that the two legs of 120 volts ac coming to your
home/studio service from the pole are the source of energy for
everything that is run. The circuit that a particular device is plugged
or wired into will be of either the 120 or 240 volt AC variety.In most
instances, in a home or studio, the pressure in the system (volts)
required to run the appliances in not more than 120volts AC. In some
instances, such as in the case of a kiln, electric stove, electric
clothes dryer, electric heater, or other energy demanding devices, the
120 volts AC of pressure is not sufficient. Because of this, the
equipment runs on two legs of the general electric feed coming into a
home or studio. There will be two hot 120 volt lines on the circuit and
one common return line. This is what is commonly called "220". Think of
it as having twice the punch/pressure. If you look at your kiln and
think about all the twists in the wires, think of the amount of
resistance that this will present for the flow of the electricity. This
is the reason that you need two legs of energy, as opposed to
one......"220" vs "120."
The other part of the equation is the "volume" of electricity
flowing through the system. The volume is measured in Amps. It is the
amount of "current" that is required to most efficiently run your kiln
when it is on high. Chances are you need at least 50 amps of current to
run your kiln at peak capacity when all of your switches are set to high
(or the computer moderated equivalent.) Once again, think of this as the
volume of energy that is available to run your kiln. So, if you think of
pressure and volume combined you will get a rough idea of what is going
on. Both of these are important. If there is one without the other then
things will not work correctly.
Sometimes, because of the amount of volume that a particular home or
studio is using, there is not alway enough volume of electricity
available. You will need to check out the type of hook up that you have.
Is your kiln wired into a completely separate service from the pole? If
it is, then is the power panel a good 200 amp service? Or, are you
taking electricity from that which feeds your home.? If it is from your
homes service, then the rating of the service is even more important.
Many homes were originally wired with a 125 amp service. If you are
running an AC unit, deep freeze, electric stove, several computers, hair
dryers, and a kiln off the same service, then the service is "too
small." It will be a good idea to jump up to a 200 amp service for the
whole deal.
There are a coupla other things that will affect the volume of
electricity that is getting to your kiln. The first is the distance from
the breaker panel, your "service", to your kiln and the size of the wire
that was used to connect the kiln's outlet to the breaker panel. I have
been calling your breaker panel a "service." The size of the wire from
the "service" is very, very important.
If the individual that hooked you up did not use a wire of
sufficient size, then there will be too much resistance in the wire and
you will not have enough volume of electricity flowing through your
kilns elements for it to work correctly. Size of wire and distance from
the breaker panel go hand in hand. The farther the distance the larger
diameter the wire needs to be. A lot of times, in order to save money,
an electrician will go with a No. 8 wire, when a no. 6 is really the way
to go. They often don't realize the high current demand of a kiln that's
running on full tilt boogie. Check out what size of wire was used and
the distance from the kiln to the power source.
The next thing to think to consider is the source of the electricity
itself, though this is less likely the problem. Your electrical provider
has what is called a power grid. The grid supplies energy to you and all
of your neighbors. The demand on the grid, as in the amount of volume,
will vary throughout the day, week, month and year. There are high
"demand" times and low "demand" times. The highest will generally be
during the day, during the summer months when everyone is running their
AC units and businesses are using their greatest amounts of electricity
as well. A quick check of this will be to attempt to run you kiln at
night and see if there is a big difference in the operation.
Get your electrician, or someone you know who really knows what they
are doing, to check the voltage level at the breaker panel. Take a
reading with the kiln off, the kiln on low, medium and high. There
shouldn't be a substantial fluctuation in the reading. Next, do the same
at the kiln. You will need to remove the panel, and this is quite
dangerous in that you will be checking a LIVE circuit with 240 volts
that can really KILL you, and see what the voltage level is following
the same procedure. This will give you an indication of what is going on.
You will also need to check out the kiln itself. Are all of your
connections from the wires to the elements good connections that are
free of corrosion. Then you will need to check out the elements
themselves. After doing what I like to call the "glow test", as in do
the elements glow when the kiln is on the different settings, then you,
or your knowledgeable electrical person, will need to check out the
resistance of the elements themselves. This is done after you have
isolated the problem with a high degree of confidence to an element
since most of teh time you will need to disconnect an element to check
it's resistance. The glow test is a great indicator.
You can get the amount of resistance of the elements on your kiln,
measure in ohms, from your either the kiln manufacturer or the maker of
the elements themselves. If the bottom and middle sets pass the glow
test fine, and the top one doesn't, or vice versa, then there could be a
problem with the element, or the switch/controller for the element..
This may sound a bit complex but it really isn't if the trouble shooting
process is done in a methodical step-by-step manner. Write every thing
down as you go.
One last thing..............awhile back a friend of mine called with
a really weird problem in his home, and the electric company had
intially said that it was a problem in his house, not with the supply.
Some things worked, others did not, lights did the flickering thing. I
didn't know what was up so I called a buddy of mine who knows more about
these types of things than I. He said that there had been some recent
heavy lightening activity in the area and that there was probably a
problem with either the hot feeds, the common return, or the transformer
itself (not as likely....they usually blow and you know it when they
do.) Turns out my bro was right. It was a problem with the common feed
line from the center tap. Problem fixed. So, also check for any such
potential problem or corrosion with connections or older supply wiring.
Here is the link to follow for an brief description of understanding
electricity....http://www.4qdtec.com/water.html
Hope this helps
Craig Dunn Clark
619 East 11 1/2 St
Houston, Texas 77008
(713)861-2083
mudman@hal-pc.org
Maurice Weitman wrote:
> At 23:43 -0400 on 10/4/06, Alyssa Ettinger wrote:
>> [...] we had 220 lines brought
>> into our studio, and got a 240 kiln because everyone said this would
>> work.
>> in fact, it did work--albeit taking longer to fire than normal--till
>> summer... and then it started not even reaching cone 6 (kiln is cone
>> 8) and
>> now throwing error message as it gets close to temp. note: this is a new
>> skutt, 1227, 1 phase
>>
>> obviously, we have heard this is a common problem (the 220/240
>> thing). and
>> that 220 is really 208. and that we need to buy/install somethng
>> called a
>> step-up converter for something like a billion dollars (kidding).
>
> Alyssa,
>
> I don't agree with your math, but don't want to contribute to your
> insanity.
>
> Here is what I think (and I am NOT an electrician or anything like one).
>
> There is no difference between what is called 220 and 240 volts A.C.
>
> And 220 is NOTHING LIKE (what is called) 208.
>
> Nominal A.C. voltage in most areas in the US is 120 volts. When
> larger appliances, such as electric dryers, ovens, ranges, large
> motors, etc., are used, they are mostly designed to use two "legs" of
> the power line so that the circuit can use smaller-diameter wiring.
> This is exactly (uh-oh!) double the single-leg voltage, so it's
> nominally 240 volts. BUT it is often referred to as 220 volts. It's
> a sloppy, but common reference.
>
> 208 is another animal altogether. It's found nearly exclusively in
> industrial settings. It is also part of what is called three-phase
> service, because its three legs are out-of-phase by 120º of each cycle.
>
> Now, assuming you have 240 volts coming into your studio and your kiln
> is designed for 240 volts AND if you have a problem with not enough
> voltage or current to you kiln, I'd say that's a problem for your
> electrician or utility.
>
> If your utility is saying that you need a step-up transformer, I'd say
> that's an indication that they're not delivering the proper voltage to
> your studio. Such a transformer is NOT the solution to your problem.
> It might work, but it will be too expensive. Worst-case is that you
> will have to re-wire your kiln with different elements to match your
> actual voltage.
>
> Have you measured the voltage at your panel?
>
> The fact that your kiln worked better before summer may indicate that
> your utility might be having problems meeting air conditioning-induced
> demands, or your studio might not be wired with enough reserve to meet
> your peak needs.
>
> If the voltage is good and your kiln is firing too slowly, its wiring,
> or the wiring to it may be bad.
>
> Regards,
> Maurice
>
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