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Three Phase Transformer Unbalanced Loading
3

Three Phase Transformer Unbalanced Loading

Three Phase Transformer Unbalanced Loading

(OP)
We have a delta-wye(solidly grounded, 600-208Y/120V, 30kVA transformer. We are intending to use it to feed 2nos-120V, 2 wire panelboards connected to phases X1-N and X2-N. Phase X3 is not connected. This will leave secondary phase C unloaded.

Is this acceptable as far as loading is concerned?

RE: Three Phase Transformer Unbalanced Loading

2
Not great, but probably not going to cause too much trouble either.

RE: Three Phase Transformer Unbalanced Loading

30 kVA = 10 kVA per phase.  Don't load the 120 V panel over 10 KVA.  Size the neutral at 100%.

RE: Three Phase Transformer Unbalanced Loading

(OP)
Thanks dpc. Good reminder rcwilson!

RE: Three Phase Transformer Unbalanced Loading

Did I just get dis'ed? How is that dpc gets thanked and he didn't even post to this thread? winky smile

RE: Three Phase Transformer Unbalanced Loading

Here you go with an LPS David. I didn't post here either but I agree with you completely.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Three Phase Transformer Unbalanced Loading

Thanks Bill.  I wasn't really fishing for a star, but this is at least the second time that dpc got thanked for a response in a thread he never posted to.  Nothing against Dave, and I usually agree with his responses, but I think he ought to have to actually post before he gets thanked for his response. winky smile

RE: Three Phase Transformer Unbalanced Loading

How can I give Dave a star in a thread where he has not posted? soapbox

RE: Three Phase Transformer Unbalanced Loading

My non-responses are generally better than my actual responses so it seems perfectly appropriate to me.  

I'll buy you a beer next time I'm up your way. cheers

RE: Three Phase Transformer Unbalanced Loading

(OP)
OOpppssss my apologies sir. I know your names aren't really that close but somehow with all the payloaders and oilsands hauler trucks around, I might have shaken a little bit.

Thank you davidbeach for your usual support (and comments as well)....I'll buy you a beer if you happen to be here at Fort Mac.

We got a 45kVA, 600-208Y/120V dry type transformer hanging around the warehouse and we used this for the above mentioned application, it for temporary power for these 1 phase panelboards.  

RE: Three Phase Transformer Unbalanced Loading

I'll buy you a coffee some day. I'll be the one at Tim Hortons with the white extended cab 4x4.
For those down south, Tim Hortons is a ubiquitous coffee and doughnut chain in Canada. White extended cab 4x4s are also ubiquitous in Fort Mac. I counted 30 in one parking lot. I've been out near the sulfur piles lately.  

Bill
--------------------
"Why not the best?"
Jimmy Carter

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