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Rewiring 3 Phase Kiln To A 1 Phase?


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#1 missholly

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Posted 12 September 2013 - 07:44 PM

does anyone have any experience rewiring a 3 phase kiln to a 1 phase? i have a skutt ks-1027, 3 phase that needs to be rewired for residential use. i have a good friend who is an electrician who is going to do it for me, but he was wondering if anyone had any advice?
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#2 neilestrick

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Posted 13 September 2013 - 08:44 AM

Piece of cake, especially for an electrician. The big difference is that the 3 phase model uses an external contact switch, and the single phase doesn't. What that means is that the kiln sitter is not actually connected to the power inside the kiln. It's connected to a cord than runs outside the kiln, to a contact switch on the wall that's connected to the kiln outlet. When you push the power button on the sitter, it turns on the contact switch, which send power to the outlet, which goes to the kiln. The 3 phase model has the leads in the power cord going directly to the 3 sections of the kiln. It does not connect to the sitter block. You'll need to get a new power cord, and the two hot leads will connect to the top of the sitter block. The feeds to the kiln sections will come off the bottom of the sitter block. Contact Skutt to get a wiring diagram for the single phase setup. You may also need to get a new set of internal wires, as the old ones may not be large enough since the 3 phase setup runs on lower amperage. If it has the old interbox plugs, I would upgrade that as well. Those plugs are a major weak point in the system.


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#3 AnnaM

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Posted 27 March 2014 - 09:11 AM

(Thought Id jump onto this thread as it's exactly what I'm querying about).

Hi Guys,
Someone offered me a kiln today that is three phase, but I only have one phase, I have a 20amp socket that I had wired in a while ago when I was going to upgrade my small kiln.

The kiln is a fairly large front loading pyrolec. The lady said it was about 8cf she thinks. It currently goes to stoneware temps.

If I have it rewired for single phase 20amp will it lose much heat at the top of it's range? Is this an easy thing to do, costly?

#4 schmism

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Posted 27 March 2014 - 01:35 PM

If I have it rewired for single phase 20amp will it lose much heat at the top of it's range? Is this an easy thing to do, costly?

 

Heres the kicker.  Im assuming your Melbourne location is Australia?  

 

If thats the case the info I can find leads me to belive that 3phase power in your area is 415v.  (i had to go look up the 3phase math again)  but if i have this right....  20amp at 415v is 14376w which should be ballpark for a kiln that size.     If your single phase is in fact 240v then you would need something in the ballpark of 60amps.      

 

In the US the kiln is classified as a continuous load (on for more than 3hrs at a time) and you would have to oversize by 20% putting you at like 71 amps ish.

 

If the above is true,  I would strongly recommend consulting a local electrician about the wireing needs of the kiln.



#5 schmism

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Posted 27 March 2014 - 02:05 PM

FYI for anyone else wanting to do this conversion....

 

You'll need to know what the total power needed is either by calculation or by manufactures spec.     For a calculated power for a Delta wired 3phase load,  its P_total=sqrt3*volts*amps*power_factor.   Power factor for resistive loads (like a kiln) is assumed to be 1.00.  (not the case for motor loads)

 

so the above went 20*415*sqrt3 = 14376 W

 

single phase is simple Watt=volts*amps  so 14376W/240V = 60A



#6 Tarheeler

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Posted 27 March 2014 - 02:44 PM


If I have it rewired for single phase 20amp will it lose much heat at the top of it's range? Is this an easy thing to do, costly?


Heres the kicker. Im assuming your Melbourne location is Australia?

If thats the case the info I can find leads me to belive that 3phase power in your area is 415v. (i had to go look up the 3phase math again) but if i have this right.... 20amp at 415v is 14376w which should be ballpark for a kiln that size. If your single phase is in fact 240v then you would need something in the ballpark of 60amps.

In the US the kiln is classified as a continuous load (on for more than 3hrs at a time) and you would have to oversize by 20% putting you at like 71 amps ish.

If the above is true, I would strongly recommend consulting a local electrician about the wireing needs of the kiln.

This is very important to remember.

If you are changing the voltage or the phase, the amp draw is going to change as well. And that means you have to recheck to make sure the breaker and line-side wiring is sufficient for the new setup.

#7 Marcia Selsor

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Posted 27 March 2014 - 03:03 PM

I did it and had to send the control panel back to skutt. The kiln had been a ^10. With the new control panel and new wiring , it became a ^5.

something they failed to mention when I hd first called about it. The kiln was at the University and had been moved to a new location where the wiring wouldn't work for 3-phase.

 

 

Marcia



#8 AnnaM

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Posted 27 March 2014 - 03:24 PM

Thanks guys, So worth taking the kiln and rewiring?

Marcia, when you say ^5, can that mean ^6 with a longer soak? Would that happen with most kilns that are rewired to single phase?

And Schism, by your calculations are you saying that changing this size kiln to single phase would still be enough to power it properly to stoneware temp? (yes Melbourne Australia btw).

Thankyou for your help with this guys- I don't understand the electrics of kilns at all yet!

#9 schmism

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Posted 27 March 2014 - 04:03 PM

And Schism, by your calculations are you saying that changing this size kiln to single phase would still be enough to power it properly to stoneware temp? (yes Melbourne Australia btw).
 

 

I dont know the specifics of your kiln.  As Neil posted above,  you may need re-wire the supply wire to the elements.  I assume that the heating elements are rated for a certain wattage,  You would think you could make that any way you wanted.  2000w is 20amp at 100v or 2 amps at 1000v  point is its still 2Kw output either way.

 

I have no reason not to believe that if you used a properly sized controller and supply that the kiln should still be able to fire to ^10 (if it did before)



#10 AnnaM

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Posted 27 March 2014 - 04:25 PM

Thanks Schism, I'm really hoping this all works out!

#11 bciskepottery

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Posted 27 March 2014 - 05:26 PM

On the kiln should be a metal plate that shows the wattage, voltage, and amps needed for the kiln. Your electrician is going to be your best friend on this. Also, contact the manufacturer and ask them about converting from 3 phase to 1 phase; they can tell you if you'll need to redo the controller, elements, etc. They might even provide a wiring diagram for your electrician.

#12 Babs

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Posted 27 March 2014 - 07:13 PM

Thanks people I will have to do this in the near future and am beginning to read up on this. Just hope that my supplier, electricity allows for this in a rural area.



#13 Marcia Selsor

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Posted 27 March 2014 - 07:29 PM

Call Skutt and talk to a tech.. The capacity changes when it goes from 3 phase to single phase.

no matter what is says on the kiln. If you change the panel box, and triple to single , it changes.

 

Marcia



#14 AnnaM

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Posted 27 March 2014 - 11:39 PM

I spoke to our kiln tech and he said don't take it as the highest amperage plug I have is 20amps (specially installed for my smaller kiln) but the kiln is 23amp 3phase, which would mean 69amp single phase which is too much for my house's power supply. No free kiln win here today!




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