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Changing kiln from 3 phase to single pahse


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#1 heatherw724

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Posted 10 November 2011 - 11:10 AM

I have recently moved to an residential area and the power is single phase.
My kiln is 3 phase, and I had an electrician, who said this would work, hard wire it so it works on only 1 phase.
Well it doesn't work and would have taken 75 hours to reach the temp I needed for cone 6 glaze.
Has anyone ever done this conversion?
The kiln manufacturer say I need new control box, new wiring and new elements, or there is phase converters.
Both are about $1,500. I am trying to get away cheap but not sure now if it is worth it, especially if it doesn't work.
Does anybody know if it is even possible to just hard wire it different to change from 3 to single phase, maybe my electrician has done something wrong?
Christmas is coming and I need to get firing, please help!

#2 Arnold Howard

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Posted 10 November 2011 - 11:22 AM

The kiln manufacturer say I need new control box, new wiring and new elements, or there is phase converters.


Ask the kiln manufacturer for the single phase and three phase wiring diagrams for your kiln. Look at them side by side. You might discover that the parts needed for the conversion are less than $1500. You may have been quoted a ball park figure.

Sincerely,

Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com

#3 Marcia Selsor

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Posted 11 November 2011 - 06:58 AM

I am in the process of rewiring a 3-phase skutt to a single phase skutt. Perry Peterson , Skutt tech. advised me to change the controp box by sending it into the manufacturer. Done. They discovered the kiln had been fired at sometime or other , but don't know when or where(I am a one-year replacement and walked into this situation).
Because the kiln had been fired, I had to replace all of the elements rather than just the 4 center element. The cost is about $790. This is for a 30" diameter kiln.

The rewiring looks simple since everything is plainly numbered.
Biggest challenge is to get the faciltiy services to install the 60 amp outlet.

Marcia

#4 Daniel Orr

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Posted 23 January 2013 - 03:33 AM

I have an oval kiln that is 208 three phase. I bought it when I had a studio that had three phase power. Now my studio is at home (240 single phase) and the tech at the company where I bought it says its the only kiln that can't be converted and he wouldn't give me any other info. Does anybody know anything about what the risks are if I have my electrician hook it up to 240 single phase? Other than trying to sell the kiln and buy a new one, I am at a loss. I was researching phase converters and saw this on clayart and wonder if anyone can corroborate,

(There is no reason to get phase converters to run a 3 phase kiln. Converters
are meant to service inductive loads like 3 phase electric motors because
with them there is no alternative to three phase current.
Simple resistive loads like kilns can be rewired to run on single phase and
when the 208 volt elements burn out, have a set of the correct elements on
hand to replace them.
Contact your kiln manufacturer to get the proper elements along with a
schematic of how to wire them and you will save thousands of dollars and
much heartache. )

Any help would be very much appreciated.

#5 trina

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Posted 23 January 2013 - 09:39 AM

I have an oval kiln that is 208 three phase. I bought it when I had a studio that had three phase power. Now my studio is at home (240 single phase) and the tech at the company where I bought it says its the only kiln that can't be converted and he wouldn't give me any other info. Does anybody know anything about what the risks are if I have my electrician hook it up to 240 single phase? Other than trying to sell the kiln and buy a new one, I am at a loss. I was researching phase converters and saw this on clayart and wonder if anyone can corroborate,

(There is no reason to get phase converters to run a 3 phase kiln. Converters
are meant to service inductive loads like 3 phase electric motors because
with them there is no alternative to three phase current.
Simple resistive loads like kilns can be rewired to run on single phase and
when the 208 volt elements burn out, have a set of the correct elements on
hand to replace them.
Contact your kiln manufacturer to get the proper elements along with a
schematic of how to wire them and you will save thousands of dollars and
much heartache. )

Any help would be very much appreciated.

Hi there, you could also consider purchasing a 3 phase generator. Quite a few people have them here to use various welding equipement and tools. That might do the trick. T



#6 neilestrick

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Posted 23 January 2013 - 10:17 AM

Most electricians I've met don't have a clue how kilns work. If seen several 3 phase kilns wired up to single phase. However you can't just hook up a 3 phase kiln to single phase service. It won't work. There won't be enough power to going to some or all of the elements. Some kilns can be rewired very easily, some can't. It just depends on how it was originally set up. Sometimes they'll need new elements, but often they won't. Again, it all depends on how it was originally set up, and if your original elements were the correct voltage. Sometimes you'll need new terminals and mounting brackets in the control box, sometimes you won't. They may lay out the parts in the control box differently for each phase, and the singel phase system just doesn't fit right with the current layout. The current wiring harness may not be adequate for the higher amperage of the single phase system. There are a lot of variables at work here. It all depends on the kiln.

Unfortunately, the manufacturer usually knows best in these situations. They're going to tell you how to do it so that it still meets their standards and fits with their systems. The problem with not doing it according to their design is that you may have a harder time diagnosing problems in the future.

If you need help, send me the info on the kiln and I'll take a look at the wiring diagrams.
Neil Estrick
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Owner, Neil Estrick Gallery, LLC
www.neilestrickgallery.com

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#7 Mark C.

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Posted 23 January 2013 - 12:27 PM

As far as converters go this statement is correct
(There is no reason to get phase converters to run a 3 phase kiln. Converters
are meant to service inductive loads like 3 phase electric motors because
with them there is no alternative to three phase current.)
I have a friend with a 3 phase band saw-the converter is just a huge motor that runs along side of the other motor. You start it with a lawn mower pull cord
Maybe a used kiln would be cheaper than all new stuff-Like Neil said call the kiln manufacture
The thing with three phase is the wire size can be smaller to the kiln as all legs are used-the down side its an industrial power source and is not run in residential areas-that is not in the burbs only in industrial areas.
For example down our hill about a mile away there once was a sawmill so 3 phase is on the power poles down there but not up our hill.-

Its a small world Marcia I know Perry as he used to live in this area.I think this is the same Perry?
Mark
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#8 neilestrick

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Posted 23 January 2013 - 12:41 PM

The thing with three phase is its cheaper more efficient to run


3 phase kilns are not cheaper to run. They use the same watts as a single phase kiln. Watts are what you pay for. But 3 phase wiring is often cheaper to install because it will require fewer amps, which means smaller wire can be used. The fewer amps also mean you can run more appliances before you max out your breaker box.
Neil Estrick
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#9 Mark C.

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Posted 23 January 2013 - 01:34 PM

Thanks for that reminder Neil-My old brain knew that back in the day we wired cheaper on 3 phase but it was wire size that was the savings not the draw. I do know all three legs draw which makes for smaller wires to the draw. I'll amend that statement.
Mark


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#10 neilestrick

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Posted 23 January 2013 - 02:13 PM

Thanks for that reminder Neil-My old brain knew that back in the day we wired cheaper on 3 phase but it was wire size that was the savings not the draw. I do know all three legs draw which makes for smaller wires to the draw. I'll amend that statement.
Mark



I'm actually glad you said it, because it is a common misconception about kilns. Good opportunity for education!

In a situation like mine the difference between single and 3 phase is significant. If my two kilns were running on single phase, my little one would need a 60 amp breaker, and my big one a 150 amp breaker. That's 210 amps for my 200 amp breaker panel. Granted, they would only pull about 160 amps, but that still doesn't leave enough for running the electric baseboard heaters in the gallery, the gas heater in the studio, my 11 wheels, the lights, etc. I would only be able to fire 1 kiln at a time.

On 3 phase my kilns only need 120 amps of breakers with an actual pull of 92 amps total. That leaves me 108 amps for everything else in the shop, which is plenty. So that's the main benefit of 3 phase. More appliances hooked up to the same size panel.

Residential settings don't typically have a lot of high-amperage appliances other than the clothes dryer, air conditioning unit and stove. And those usually only need a 30 amp breaker each, leaving plenty of power left for lights and small appliances. Commercial space use a lot more power- more large appliances, more lights, etc, so 3 phase is generally available for them.
Neil Estrick
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#11 Daniel Orr

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Posted 23 January 2013 - 03:02 PM

Thank you. I think I may have an idea. I was researching and found out that skutt makes an oval kiln that can run on single phase but can only reach cone 1. My guess, and I'm not really sure cause I can't seem to wrap my head around all of the electrical, is that the reason my kiln, amaco ex-1850, can't be converted is that firing it to cone 10 wouldn't be advisable and safe as well as not being able to get UL to list it. It seems that Skutt figured it could get a UL listing if the top end was cone 1. That said amaco has a wire diagram on their website that shows the 1850 in single phase. Hmmm...? What is this about? Aren't amaco kilns and skutt kilns the same? I guess my question now is if I can get a new terminal block, two ins instead of three, and make sure the wiring is the correct gauge, get new 240 elements and never fire above cone 1 will it work? Any thoughts?

I think I have all of the breaker stuff worked out as I got new service, 225amp, to my house. I dug a trench and ran lines to my studio so that the studio would be able to have a 100amp breaker dedicated to the kiln as the manufacturer recommends. I had an electrician hook it all up and guide me as to the gauge of wire.

Thanks for all of the amazingly quick input from the people that have replyed to my post. I am new to this forum and I am impressed by what I have seen. I look forward to interacting often in the future.

Dan

#12 Mark C.

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Posted 23 January 2013 - 03:37 PM


Thanks for that reminder Neil-My old brain knew that back in the day we wired cheaper on 3 phase but it was wire size that was the savings not the draw. I do know all three legs draw which makes for smaller wires to the draw. I'll amend that statement.
Mark



I'm actually glad you said it, because it is a common misconception about kilns. Good opportunity for education!

In a situation like mine the difference between single and 3 phase is significant. If my two kilns were running on single phase, my little one would need a 60 amp breaker, and my big one a 150 amp breaker. That's 210 amps for my 200 amp breaker panel. Granted, they would only pull about 160 amps, but that still doesn't leave enough for running the electric baseboard heaters in the gallery, the gas heater in the studio, my 11 wheels, the lights, etc. I would only be able to fire 1 kiln at a time.

On 3 phase my kilns only need 120 amps of breakers with an actual pull of 92 amps total. That leaves me 108 amps for everything else in the shop, which is plenty. So that's the main benefit of 3 phase. More appliances hooked up to the same size panel.

Residential settings don't typically have a lot of high-amperage appliances other than the clothes dryer, air conditioning unit and stove. And those usually only need a 30 amp breaker each, leaving plenty of power left for lights and small appliances. Commercial space use a lot more power- more large appliances, more lights, etc, so 3 phase is generally available for them.



Another way to think about this is in 220 single phase both legs are hot (two hot wires)and a neutral wire-this totals 220V at your kiln with say #6 wire for 60 amps-with 3 phase all 3 legs are hot (3 hot wires) with another neutral wire.
Most 220 appliances use all the power and sends none back vs 110 volt stuff does not use it all and sends some back via the neutral wire
One can google 3 phase to see the diagrams. Hence the load is spread out more which is these amps per wire needed as Neil says above.

Back when i worked as an electrician we wired many a commercial appliance with 3 phase.
My last 3 phase was as a diver wiring a 3 phase generator to our 3 phase compressor for a 3 week tanks job in 2007. Sucking 15 feet of mud in zero visibility. My last tank job ever-I had done this once before as well-I must be slow learner.
Heres what i looked like as well as the tank and air supply bottles
Mark
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www.liscomhillpottery.com

#13 neilestrick

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Posted 23 January 2013 - 04:35 PM

Dan,
I sent you an email on this, basically discussing what you said above. If cone 1 works for you, then it's the best fix. However for $1500 you can probably find a like new Skutt KM1227 used and be able to get to cone 10.
Neil Estrick
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#14 Daniel Orr

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Posted 23 January 2013 - 05:49 PM

Thank you all. I will post when I get it up and running and have completed a glaze firing.

#15 Marcia Selsor

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Posted 23 January 2013 - 08:12 PM

After my conversion of a cone 10 three phase to a single phase, the kiln came back as a max. Temp. Of cone 5 labeled on the control box. I was not informed that that would be the case prior to the conversion. I used it for bisque firing mainly, but it would have been nice to know before hand. do ask first.
marcia

#16 Mark C.

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Posted 23 January 2013 - 09:39 PM

After my conversion of a cone 10 three phase to a single phase, the kiln came back as a max. Temp. Of cone 5 labeled on the control box. I was not informed that that would be the case prior to the conversion. I used it for bisque firing mainly, but it would have been nice to know before hand. do ask first.
marcia

Marcia
If you replaced the control box and all new elements I wonder why the cone 5 max if it was a cone 10 max before-what's left to replace?maybe the switches?
Mark
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#17 neilestrick

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Posted 24 January 2013 - 10:40 AM


After my conversion of a cone 10 three phase to a single phase, the kiln came back as a max. Temp. Of cone 5 labeled on the control box. I was not informed that that would be the case prior to the conversion. I used it for bisque firing mainly, but it would have been nice to know before hand. do ask first.
marcia

Marcia
If you replaced the control box and all new elements I wonder why the cone 5 max if it was a cone 10 max before-what's left to replace?maybe the switches?
Mark



On larger round kilns, like the Skutt 1227 or L&L E28T-3 (10 cubic feet models) and others, if they are running on 208 volts at single phase they can't get enough wattage to get them to cone 10 and still come in under 50 amps, which is what they need to do to keep from having to change a lot of things in the wiring system, and it probably has something to do with the UL listing as well. They both do make kilns of that size that can get to cone 10 on 208V 1P, but those are different models, with different wiring setups.
Neil Estrick
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#18 Beans

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Posted 25 January 2013 - 05:23 PM

[quote]On larger round kilns, like the Skutt 1227 or L&L E28T-3 (10 cubic feet models) and others, if they are running on 208 volts at single phase they can't get enough wattage to get them to cone 10 and still come in under 50 amps, which is what they need to do to keep from having to change a lot of things in the wiring system, and it probably has something to do with the UL listing as well. They both do make kilns of that size that can get to cone 10 on 208V 1P, but those are different models, with different wiring setups.
[/quote]

[/quote]



On the topic of 208V 1P cone 10 kilns, I recently purchased a used Skutt 1227 with this configuration. I will be firing it on 240V. From what I understand after speaking with a Skutt tech it should work fine, but the life of the elements will be reduced. I was hoping to fire it a couple of times before replacing the elements (with 240V ones), I will be firing to cone 6. Do any of you see a problem with this? Should I just bite the bullet and change the elements before firing it all?

Thanks for any advice.

Jilly

#19 neilestrick

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Posted 25 January 2013 - 06:18 PM

Those elements will be running hotter than they are intended, so their life will be shortened. It shouldn't hurt anything, though. Go ahead and use them till they fry.
Neil Estrick
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#20 Beans

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Posted 25 January 2013 - 09:31 PM

[[quote]quote name='neilestrick' date='25 January 2013 - 06:18 PM' timestamp='1359155921' post='28512']
Those elements will be running hotter than they are intended, so their life will be shortened. It shouldn't hurt anything, though. Go ahead and use them till they fry.[/quote]
[/quote]

Thanks Neil, that's what I had figured. I will commence with frying!

Jilly




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