480/3-240/3 xfmr

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anbm

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Does anyone know what is maximum 480/3 (pri)-240/3 (sec) transformer size (kVA) available in the market?
Power company won't ever provide 240/3 secondary transformer, correct?
 
anbm said:
Does anyone know what is maximum 480/3 (pri)-240/3 (sec) transformer size (kVA) available in the market?
Power company won't ever provide 240/3 secondary transformer, correct?
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Probably up to 500kVA would be common.

In my experience, many POCOS won't provide 240 delta service anymore. The ones I have come across that do will only supply it via overhead, not via pad mount.
 
anbm said:
Does anyone know what is maximum 480/3 (pri)-240/3 (sec) transformer size (kVA) available in the market?
Power company won't ever provide 240/3 secondary transformer, correct?
Click to expand...
For every POCO that says they won't supply 240 3 phase 4 wire service there are others that love them depending on the size and nature of the load. Most that still do them won't likely want to see a total demand load of 150 KVA or so before they will require you to take a wye service.
 
1) Remember that you can 'bank' single phase transformers. 333 kVA 480:240 transformers are listed, so a bank gets you 1MVA.

2) Do you _need_ 240V delta, or would 240/139V wye work for your application?

Jon
 
winnie said:
1) Remember that you can 'bank' single phase transformers. 333 kVA 480:240 transformers are listed, so a bank gets you 1MVA.

2) Do you _need_ 240V delta, or would 240/139V wye work for your application?

Jon
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Number 2 ever provided from the POCO? Might explain some oddball readings was getting on one site. How critical would having that L/N voltage be if you have quite a few 120V loads?
 
winnie said:
1) Remember that you can 'bank' single phase transformers. 333 kVA 480:240 transformers are listed, so a bank gets you 1MVA.

2) Do you _need_ 240V delta, or would 240/139V wye work for your application?

Jon
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2) 240V.
 
electrofelon said:
In my experience, many POCOS won't provide 240 delta service anymore.
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I just did a new 240 Delta 300kVA, to my suprise POCO said no problemo.
Interesting design, building had all 240V 1 phase lighting and servers.
very little 120V other than 120V recepts.
The owners acted like they were allergic to anything else LOL.
Jraef said:
If I needed 6,250A at 240V, I would be buying my power at 12.47kV bulk rates and owning my substation. Then you can do what you want.
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Agreed thats a massive load.
 
electrofelon said:
Yeah I have one in my turf that will but overhead only. I guess they don't want to stock 240 Delta pad mounts....
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Yeah, a lot of poco’s will keep a spare in the yard, and they don’t like to keep that kind of money collecting dust for just one customer. They do make an enclosure that converts pole mounts to pad mount, but it’s pretty large. Especially one that size. Our local poco would do that with 480 volt services because hardly anyone had 480 three phase on their buildings at that time.
 
With that much load, does it even make sense to put it all on one transformer? If it's a big enough building, you might be saving money by running a few 480V feeders around to transformers that are closer to the loads. Remember, the cables are half the size for the same kVA at 480V.
 
petersonra said:
probably be better off just making your loads 480V.
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Yeah for sure if he can have say, or pick out different equipment.
More and more often its computer PSU's that want '240' not 208.

However I wonder if anyone has 'run the numbers' dollars per watt on the install of say a 300 kVA service, 240 D vs 480Y?
I admittedly never have, but
240V stuff is much less expensive and you get some 120V with no added xformer, and less NFPA 70 arc flash hassle.
Look at the cost of a 480V panelboard vs a 240/120D loadcenter
 
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