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Kiln wiring three phase

4K views 31 replies 5 participants last post by  mpoulton 
#1 · (Edited)
Sorry if this is posted somewhere but time is an issue so thanks in advance.

The kiln is rated for 600v at 60 amps. It is heating super slow. What it is hooked up is I believe 480. One leg to ground measured 2** and the other two were 12*. I can't remember the exact numbers. I think it's either getting a step up transformer or changing the elements.

The three hot legs from one 60a breaker run into one relay split into two relays that are feeding the elements. Essentially split. The first relay is basically a safety switch.

So can I isolate the entire 60 amp breaker to one relay, it is rated for 60, and get another breaker for the other relay to give this kiln enough power? Or would the voltage still be insufficient?

Thanks for the help.
 
#2 ·
There's a voltage problem, it sounds like. You have it connected to a "high leg delta" system, which provides 240V between phases (nominal voltages to ground are 120, 208, and 120). If the kiln is rated for 480V, then you're supplying a quarter of the power it requires (half the voltage). Can you post a picture of the kiln's nameplate that shows the rated current and voltage?
 
#5 ·
I believe this kiln was built for a company in Oregon or washington. Could be wrong. So am I able to give each relay it's own power source instead of splitting one breaker? I have the manufacturers quoting new elements which is not going to be cheap. Or a step up transformer, again not cheap and not educated on those either.
 
#6 ·
That is an absolutely massive kiln. It requires a 600V supply. It might be usable on 480V, but at reduced power. You will not be able to use it with your existing service. The transformer that would be required to power it will cost more than the kiln, and your panel probably doesn't even have enough capacity to handle the additional load of about 130A.

I'd say to sell that kiln and get one that works on a 240V supply.
 
#17 ·
Nope, won't work. You need a 240V delta primary, 600V delta or 347/600V Y secondary. If you can find a used transformer for cheap that will work, and if your existing panel can handle the load, then you could do it. However, I would not expect to find the right transformer at a reasonable price.

It might be possible to re-wire the elements in the kiln to work with your supply. It depends on how the individual elements are configured. Many high-power heating devices use a bunch of smaller elements, and are reconfigurable for different voltages and phase configurations by rewiring the elements. However, I don't think this project is within your skill range. In fact, this entire installation is probably not something you should be doing. This is clearly commercial work, which generally must be performed by a licensed electrician. Also, higher line voltages like 277 and 347V are very dangerous, and transformers require a professional level of knowledge to install safely.
 
#19 ·
I appreciate the help very much as well as the recommendations per safety reasons. I really just needed the info to see what my options are with this kiln. It doesn't need to run at 100% power but I would like it to heat faster than it does right now. Thanks again.
 
#20 ·
There is couple thing it kinda show semi red flag half way up so let me ask you a basic question here.

A) What size service ( main breaker ) you have in your place ?

B) What voltage and phase you have in there ?( not for the kiln but for whole system )

If not sure you can post a photo otherwise a electrician can asssit you on this one.

However if you have single phase service you will denfitally need more than just a 200 amp service due your kiln size is pretty huge but if three phase it depending on main breaker rating / voltage you have there as I posted the question above.

Merci,
Marc

Note : normally three phase system is generally best done by electrician due can get tricky with connection if not heeded on that.
 
#23 ·
As long as it's rated at more than 47 KVA it'll work for the kiln. The difference between 575 and 600 is too small to matter.

Even though it's technically not completely correct, a 45 KVA would work if it was fan cooled and installed in a fairly cool environment.

Dry-type transformers are almost always rated for installation in still air at 104ºF.

Most dry-type substation transformers I work with have two KVA ratings, one for AA (atmospheric aspiration) and a higher one for FA (forced aspiration).

Just last week, I added a new feeder to a switchgear that was fed from a dry-type transformer that was rated 1500 KVA AA and 2000 KVA FA.

Rob
 
#24 ·
47 KVA @ 240 3ø = 113 amps.

There'll be some loss in the transformer, but not very much.

If you're driving a 600 volt kiln with 575, the actual current will be a bit less.

Using the transformer described above, the 240 volt current will be somewhere around 100 - 115 amps, depending mostly on exactly what voltage the 240 runs at.

Rob
 
#26 ·
I have get access to the main panel later, but this is in an industrial building with many bays. Luckily I'm the only one that uses electricity. Shouldn't the transformer only draw 180 amps? Another option I am considering is only going up to 480v which would allow the kiln to run at 64%. Any thoughts?
 
#27 · (Edited)
180A? It should be 113A, plus whatever the losses in the transformer are. Although I think the nameplate says the load on each phase is not completely balanced, so one phase might be a bit more. If there are any other substantial loads on the panel, you're likely to overload it. More importantly, like I said, you're likely going to overload the high leg of your service since it was never intended to supply such a large 3-phase load.

Edit: You should have two phases running 125A and one phase at 108A, plus transformer losses.
 
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