Roger Korn on mon 6 jan 03
Hi Nanci,
The solid-state relays can fail closed, as can the conventional
electro-mechanical relays (welded, worn contacts). The working life of a
solid-state relay is better than ten times that of the conventional
relay, however. In either case, a kiln sitter, used as you suggest,
provides good protection against "melt-down". Wouldn't hurt to "be
there" when the kiln is supposed to peak, however. After 40 years of
messing with kilns and a career as a physicist and engineer, I still
don't trust anything with the potential of causing great badness, so I
set an alarm to wake me up if I'm firing at night. Never could sleep
very well anyway.
Roger
Nanci Bishof wrote:
>I would definitely stay away from the solid state relay. It can fuse in the
>closed position causing a constant flow of electric to your elements. I would
>also install a Dawson Kiln Sitter in line that you place an Orton Bar one
>cone higher than your end firing cone. It would cut off electric to the unit
>should you experience an overfire.
>
>nanci
>
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--
Roger Korn
McKay Creek Ceramics
In AZ: PO Box 463
4215 Culpepper Ranch Rd
Rimrock, AZ 86335
928-567-5699 <-
In OR: PO Box 436
31330 NW Pacific Ave.
North Plains, OR 97133
503-647-5464
Terrance Gallentine on mon 6 jan 03
I have been looking for some economical temp controllers that still have
ramp/soak functions. What I found was the Omega model CN4321. It appears
to have the functions that I need for my glass kilns and at a price of $129.
It can be used with either a mechanical contactor or a solid state relay.
The solid state relay with a 75 amp capability runs around $65. Has anyone
had any negative or positive experiences with this type of controller? In
regard to the relay, are there more possible failure problems with the solid
state relays than with the mechanical contactors? Any info would be
appreciated.
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Arnold Howard on mon 6 jan 03
Before using a solid state relay on a kiln, you should find out
what happens should it fail in service. If the relay fails in the
electrically closed position, it will overfire your kiln. If it
fails in the open position, it will merely shut off power to the
elements.
Arnold Howard
Paragon
--- Terrance Gallentine wrote:
> I have been looking for some economical temp controllers that
> still have
> ramp/soak functions. What I found was the Omega model CN4321.
> It appears
> to have the functions that I need for my glass kilns and at a
> price of $129.
> It can be used with either a mechanical contactor or a solid
> state relay.
> The solid state relay with a 75 amp capability runs around $65.
> Has anyone
> had any negative or positive experiences with this type of
> controller? In
> regard to the relay, are there more possible failure problems
> with the solid
> state relays than with the mechanical contactors? Any info would
> be
> appreciated.
>
>
>
>
>
> _________________________________________________________________
> MSN 8 with e-mail virus protection service: 2 months FREE*
> http://join.msn.com/?page=features/virus
>
>
______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your
> subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
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Roger Korn on mon 6 jan 03
Solid-state relays using thyristors can fail in either open or closed
mode. You should use a kiln-sitter or other, controller-independent form
of over-temperature protection.
Roger
Arnold Howard wrote:
>Before using a solid state relay on a kiln, you should find out
>what happens should it fail in service. If the relay fails in the
>electrically closed position, it will overfire your kiln. If it
>fails in the open position, it will merely shut off power to the
>elements.
>
>Arnold Howard
>Paragon
>
>--- Terrance Gallentine wrote:
>
>>I have been looking for some economical temp controllers that
>>still have
>>ramp/soak functions. What I found was the Omega model CN4321.
>>It appears
>>to have the functions that I need for my glass kilns and at a
>>price of $129.
>> It can be used with either a mechanical contactor or a solid
>>state relay.
>>The solid state relay with a 75 amp capability runs around $65.
>>Has anyone
>>had any negative or positive experiences with this type of
>>controller? In
>>regard to the relay, are there more possible failure problems
>>with the solid
>>state relays than with the mechanical contactors? Any info would
>>be
>>appreciated.
>>
>>
>>
>>
>>
>>_________________________________________________________________
>>MSN 8 with e-mail virus protection service: 2 months FREE*
>>http://join.msn.com/?page=features/virus
>>
>>
>______________________________________________________________________________
>
>>Send postings to clayart@lsv.ceramics.org
>>
>>You may look at the archives for the list or change your
>>subscription
>>settings from http://www.ceramics.org/clayart/
>>
>>Moderator of the list is Mel Jacobson who may be reached at
>>
>melpots@pclink.com.
>
>
>__________________________________________________
>Do you Yahoo!?
>Yahoo! Mail Plus - Powerful. Affordable. Sign up now.
>http://mailplus.yahoo.com
>
>______________________________________________________________________________
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
>
--
Roger Korn
McKay Creek Ceramics
In AZ: PO Box 463
4215 Culpepper Ranch Rd
Rimrock, AZ 86335
928-567-5699 <-
In OR: PO Box 436
31330 NW Pacific Ave.
North Plains, OR 97133
503-647-5464
Nanci Bishof on mon 6 jan 03
I would definitely stay away from the solid state relay. It can fuse in the
closed position causing a constant flow of electric to your elements. I would
also install a Dawson Kiln Sitter in line that you place an Orton Bar one
cone higher than your end firing cone. It would cut off electric to the unit
should you experience an overfire.
nanci
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