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How Can I Convert A Large 3 Phase Kiln To Single Phase?

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I have the opportunity to buy a large 3 phase kiln - metal frame, ceramic fibre - 900mmx800mmx800mm with lots of added kiln furniture... so it is very tempting.  I really want it for its size but it uses 3 phase which I do not have. I am on acreage and the cost of bringing 3 phase to my house is too much. It draws 37.5 amps. I have a 40amp line from our switchboard on our house to another small switchboard in our studio shed. I like to consider the kiln as a large shell to which I could place new elements and rewire with a new controller. If I could do this for $2-4,000, I would then have a large single phase kiln for a third the price of a new one. Or...I could convert it to gas but it would probably cost a fortune to pass new regulations in Australia. Has anyone done this before and can give advice?

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Three phase conversions can cost a pretty penny-you will need a converter which in itself uses more power.

!st your 40 amp line is to small even for a 37 amp draw-you need more room for safety.

I have had somme experience with phase converters on fixed machinery but not kilns-as they are a constant draw.

I think since you do not have 3 phase and as you have found out it will cost more than its worth I would not even consider this . The only thing that made any sense was converting the shell to gas.

One last note since its a fiber kiln rewiring it to single phase working with the stiff fired fiber will damage it. Fiber is best left alone once fired. Once its converted to single phase it will draw a lot more amps as any single phase does.

Thats the beauty of 3 phase for industrial equipment. They demand lower operating costs and pay for the power grid lines to bring in 3 phase. Like a sawmill once down the road.
Since we (I also do not have it close-over 1 mile) its not in the cards

I suggest passing the whole deal up as its not a fit that will work no matter how good it sounds

Your only other idea is what has been suggested above contact the manufacture sand ask them the details-I think you will find this is a poor fit.

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If it's pulling 37.5 at 3 phase, it will pull about 65 amps at single phase, which will require an 80 amp breaker. Depending on how it's built and local codes, that could mean a major rewiring, including fused branches inside the control box, bigger relays, etc. You'll need to check with the manufacturer. They will be able to tell you what's needed.

mark35085 and Pres like this

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They demand lower operating costs and pay for the power grid lines to bring in 3 phase. 

 

 

3 phase kilns do not cost any less to operate. Firing costs will be the same regardless of phase. Watts are what heat kilns, not amps, and watts are what you pay for. Regardless of the amperage, the watts will be the same.

Pres likes this

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This isn't all that complicated but you will need some wiring diagrams to do it. You will need all new elements rated for 240 v not 208 v which is typical on 3-phase. Google this. There are good instructions available.

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You will need all new elements rated for 240 v not 208 v which is typical on 3-phase. 

 

You generally only need new elements if you will be running it on different voltage than what it was originally set up for. I see a lot of 240 volt 3 phase kilns.

 

Here in the U.S., if kilns are pulling more than 50 or 60 amps (can't remember which for sure), there has to be branch fusing in the kiln control box, not just a bigger fuse on the wall. Lots to consider if you plan to do it safely and legally. Call the manufacturer.

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You got me on that one Neil watts are what costs

I guess you get what you pay for on free advice

I should have said 3 phase is more efficient

Sorry about that error on my part

 

No worries, Mark.

 

The only real benefit to running kilns on 3 phase is that it allows you to get more watts with lower amperage. Lower amperage means smaller wires, which cost less when getting the electrical service set up. It also means being able to run more kilns on a standard 200 amp service without maxing out the breaker box.

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I have worked on three phase scuba compressor(hooked it up to portable trailerable 3 phase generator for a dive job we did10 years ago) and 3 phase band saws (a friend bought a 3 phase saw and needed a converter installed) as well as working on a historic Inn back in the day with 3 phase equipment as an electrician in the 80's.

I have many wood workers who pass up lots of 3 phase equipment  as its a pain to use converters .

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we are going to lose this original poster.  he is in australia and thinks spending $2,000 to $4,000 is a reasonable cost in his money in his country.

 

It was the 1st post for them-They will have to upgrade the electrical feed to shed no mater what . 

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we are going to lose this original poster.  he is in australia and thinks spending $2,000 to $4,000 is a reasonable cost in his money in his country.

 

Old lady, kilns are super expensive in Aus. but so is having any change to electricity supply to property, tradesmen and the like, it is all related.

He will hav eto do the costing of all the above, versus a single phase kiln to decide whether this is in fact a good deal.

Manufacturer and power supply communication would be the way to go before purchase. I , with advice from this forum, courtesy Neil, went for single phase after doing a few sums.

B

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I'm in the same boat, Paragon Viking 273 from local college.  208V 3 ph  has 8 elements, top 2 and bottom 2 measure 26 ohms/16 gauge-assuming Kanthal A1 @ .33 ohms/ ft 26 ohm/.33 ohm/foot=78 foot x12 x .156=144 sqin calcs show that at 240V I  would be drawing 15 Watts /sqinch which I think is a safe loading.

The middle 4 elements are another story, again 16 gauge but 8.7 ohms  run in series 49 sqin x2=100 sqin @3310 watts give me 33 watts/sqinch a bit too high I think.  Howe about running 3 middle elements in series and just leave the 4th disconnected.

8.7 x 3 =26 ohms again with 150 sq inches  240x240/26=2215watts divided by 150 sq in =14 watts /sqin.

Does this look even close?  Can I fire these elements in their groove at this level? they are really not in free air!

A little more info - 6 mercury relays are  rated 35A @ 600V each

have 80 A breaker in panel available (have a big welder)

If I'm out to lunch please let me know

Jim

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I'm in the same boat, Paragon Viking 273 from local college.  208V 3 ph  has 8 elements, top 2 and bottom 2 measure 26 ohms/16 gauge-assuming Kanthal A1 @ .33 ohms/ ft 26 ohm/.33 ohm/foot=78 foot x12 x .156=144 sqin calcs show that at 240V I  would be drawing 15 Watts /sqinch which I think is a safe loading.

The middle 4 elements are another story, again 16 gauge but 8.7 ohms  run in series 49 sqin x2=100 sqin @3310 watts give me 33 watts/sqinch a bit too high I think.  Howe about running 3 middle elements in series and just leave the 4th disconnected.

8.7 x 3 =26 ohms again with 150 sq inches  240x240/26=2215watts divided by 150 sq in =14 watts /sqin.

Does this look even close?  Can I fire these elements in their groove at this level? they are really not in free air!

A little more info - 6 mercury relays are  rated 35A @ 600V each

have 80 A breaker in panel available (have a big welder)

If I'm out to lunch please let me know

Jim

 

Not sure what your question is here. If you want to fire it on single phase, but it's currently wired for 3 phase, call the manufacturer. They are the only ones who can give you the correct info you need to convert it.

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I did this with a Skutt at the University in Brownsville. I had to send the controls panel back to them and get a different one. It had been a ^10 one phase. What they sent back was ^6 and I had to install new elements to the new controls panel. They had never mentioned that it lowered the firing temp. when they were advising me on this.

Marcia

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I did this with a Skutt at the University in Brownsville. I had to send the controls panel back to them and get a different one. It had been a ^10 one phase. What they sent back was ^6 and I had to install new elements to the new controls panel. They had never mentioned that it lowered the firing temp. when they were advising me on this.

Marcia

 

If it was going from 3 phase to single phase, they probably lowered the max temp to keep it on the same breaker, so you wouldn't have to upgrade the electrical service.

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Hii

 

It might be attainable to change over the kiln from 3 phase to single phase; it relies on upon the model. You may need to redesign the wires in your kiln's change box to handle the higher amperage of single phase. 
 
In changing over your kiln, you won't not need to change the warming components. In the event that your 3-stage system is Delta, which implies there is no unbiased, you can most likely utilize the same components. In the event that your framework is Y, which implies there is a nonpartisan, you will require new components.
 
Thanks

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Well, I wired my Paragon 273 as I described and it works perfect! draws 39 amps at 240-all the controls work fine, every thing is great.

Hope this helps anyone else in this situation.  reading up on the expected power density of the elements vs surface area I think was the key

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