We are buying a furnace that will be manufactured with 480 delta.
How do I determine if we have 480 delta or 480 wye in our panel? (other than carefully)
Is it true that 480 delta can be run from either 480 delta or 480 wye, and that 480 wye equipment can only be run from a 480 wye source (as was listed in one post)?
CD
You talk to your plant maintainence folks, who will want to know about this thing, and know the answer to your real question.
--Dale
I agree that they should know this answer, but we are a small shop with limited capabilities. Since they did not know the answer, I seek outside help.
Your facility should have a one-line diagram of the electrical system, which shows the power configuration.
Any load that only requires three wires, whether connected wye or delta internally, will run fine on either a delta or wye supply system. If the load requires four wires then the supply would need to be a wye in order to provide the neutral.
If the furnace is wired delta, then it only needs three wires and will work fine on any 480 volt three-phase system. It doesn't matter how the supply transformer is wired.
Ben Miller
Thank you Ben.
Good answer, but what about 4 wire delta?
-> Good answer, but what about 4 wire delta?
You are not likely to find that on the load side. A typical four-wire load would be a wye with neutral. That would not work on a four wire center-tap delta supply. At some point, you need to pay attention to wiring diagrams and understand what kind of power system you have!
Ben Miller
- Benjamin D. Miller, PE B. MILLER ENGINEERING
I don't recall ever having seen a piece of factory-built equipment that needed a 480V 4 wire supply. Other than in premises wiring, where there are rules that change above 300V, why would a machine tool, for example, need 277V single phase?. I'm sure there is a reason, but I don't know what it is.
I agree. I have never seen one either on 480. I was just telling him that on a general basis, if there was one it would need a four-wire system feeding it.
Ben Miller
---------------------------- I believe that there are installations in some office buildings where the fluorescent lighting is 277V. This may be more common in Canada than in the US.
Oh yes, absolutely, that is common in the US. However, those are really single phase loads connected to a 3 phase 4 wire premises wiring system. Certainly 277 volt single phase loads exist and require a wye supply system.
My point is that I have never seen a 480 volt 3 phase machine tool or other factory-built piece of utilization equipment that requires a neutral connection.
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