Gerry Turner on wed 22 mar 00
------------------
Oh boy, do I need help=21 In the first place I live kind of out in the =
woods sort
of under a rock with no kiln gurus anywhere near.....or far either so far as=
I
know. About a year ago one of the switches on my Duncan 1029 kiln blew
up.......literally. Sparks, smoke, the whole pyrotechnic display. Right in=
the
middle of a firing for no reason that I understand even now. So I replaced =
the
switch (infinite type) and various lead wires that melted and singed in the
process. Also changed the circuit breaker from a 45 amp. to a 60 amp. at
someone's suggestion. The kiln is about 25 feet from the breaker panel and =
is
wired directly. I also replaced the block that controls the kiln setter. =
But
the kiln has never been the same. It had been taking longer and longer to =
fire
and finally wouldn't go anywhere. Guess what......another switch burned =
out.
So that is replaced. Continuity on all the elements checks out. All three
banks of elements get some heat but not more than maybe 500 degrees. A =
friend
suggested maybe the circuit breaker was faulty and it seemed to be.........I
couldn't get a reading with a neon light tester on one side of the breaker, =
so I
got a new breaker, 50 amp. 'cuz that's all they have in my metropolis of =
1100
souls, and installed it. Turned on the kiln.......empty because I don't =
want
to keep loading and unloading........but after 6 hours on high nothing =
happened
except that it warmed up, sort of. What am I doing wrong? Is there =
something
in that kiln sitter that I'm overlooking? I don't understand why two =
switches
have burned out in a kiln that has not been fired more than 50 or 60
times...........albeit over fired to cone 8+ two or three times. Do you =
think I
should bypass the kiln sitter? Where else can I look? (I know, everybody =
is
thinking about leaving or has left for NCECA, but I'm home alone and =
climbing
the walls. Help?)
Gerry in Wisconsin where the ice went out a month early but the birds are =
still
flocking to the feeder even though the sandhills are dancing across the =
valley.
Brad Sondahl on thu 23 mar 00
When troubleshooting electric kilns, consider anything that happened,
and anything you've done. In this instance you replaced the breaker,
and there could be a bad connection at the breaker, or it could have got
reconnected as 110v (unlikely). Test for 220v at the kiln.
When switches die, which really is fairly common, they can arc and
create a mess as you describe. It doesn't reflect on what caused it.
Infinite switches are constantly popping on and off, and don't last as
long as 3 position ones, and can't bear as high load either. It is
possible that the arcing damaged the lead wires to the element so that
they need to be totally replaced. Can you check for 220 volts on the
switch itself.
As to checking elements, continuity is good, physical inspection is
better, because a section could be fused and passing electricity but
pretty shot. When the kiln is not on, you can run a screwdriver along
the course of each element, and you'll notice if there is a gap.
50-60 firings is about average for element length, although they should
go longer if you're firing at midrange temperatures.
Kiln sitters (mechanical ones) are on or off affairs, so it's not likely
to be the source of the problem, unless it's electronic and kinky.
So check for electricity at all accessible points--starting at the
switches and working back through the kiln if necessary. If all the
elements aren't firing, suspect the supply of electricity coming into
the kilnsitter, switches, etc.
Hope this helps
--
Brad Sondahl
New commercial pottery page http://sondahl.safeshopper.com
http://www.camasnet.com/~asondahl/bradindex.html
Sondahl homepage http://www.camasnet.com/~asondahl
Original literature, music, pottery, and art
Ray Aldridge on fri 24 mar 00
At 06:11 PM 3/23/00 EST, you wrote:
>----------------------------Original message----------------------------
>When troubleshooting electric kilns, consider anything that happened,
>and anything you've done.
(snipped very good advice)
>
>Kiln sitters (mechanical ones) are on or off affairs, so it's not likely
>to be the source of the problem, unless it's electronic and kinky.
Just a data point-- I had trouble with one of the contact surfaces on one
old kilnsitter-- one of the element circuits failed in midfiring, and since
the elements were almost new, I looked elsewhere. When I took the
kilnsitter apart, one of the contact leaves was so badly pitted from arcing
that it was no longer working. I sanded down both sides of the contact,
and it started working again, but eventually I'll have to replace the
contact, which is not very expensive.
Ray
Aldridge Porcelain and Stoneware
http://www.goodpots.com
Pennie/Jim on fri 19 jul 02
My old electric kiln is drawing twice as many amps as it should. What is
the
problem? The kiln works just blows the breaker when I bisque pot. Any
advice
would be appreciated,
thanks. Pennie
>
>
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Wyndham Dennison on mon 21 apr 08
>
> will get to good wiring on the cord. It doesn't look that badly damaged. Of course the plug and
> receptacle are history. This kiln has been plugged in to the same circuit for a good ten years and
> has done many firings, mostly to cone 04 and 06. The plug has never even gotten hot before this.
> The wire run from the main box is about 3 feet
Laurie, This is a common problem with electric kilns I have used. I'm
surprised that this has not happened earlier. The electricity surging
through the line heats & expands the plugs then cools and contracts. At
some point some arcing occurs and more heating at the plug til either a
short or other failure occurs. This can also happen at your relays in
the kiln controller or in the connection to the elements and one can
lead to the others problem resulting sometimes of several problem
cascading at once. Electricity can be thought of as a hammer hitting
each time the controller turns on. In a digital controller this may
happen hundreds of times a firing. A breaker may also be less than
optimal after 10 yrs of service and at the small cost of a breaker, it
might be wise to replace it when the plug is replaced. The cord may have
been weakened further back than it appears, as copper can oxidize from
the heat and become a problem.
I have had these same problems on several kiln and have found out it was
cheaper to replace the breaker, the wire and the plug as well as check
the condition of the relays in the controller, than to just replace the
plug. This maybe over kill but maybe not.
I hope this helps, I sure others here have had some of the same problems
as well. Wyndham
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