XFMR Single phase the 3 Phase

[Zyb]

Hi,
I'm planning to buy a transformer, would the transformer (image below) work? and can you also verify my drawing. Thanks

1. is there a single phase to three phase Y transformer?
2. is my 20A fuse correct [(1.25 x 11,400) / (480 x 1.732)]?
3. is the ground wire correct?
4. on the 480V side how many conductors should be connected to the transformer?
5. if there are two SE11400H-US inverter does this mean that 30kVA is enough?

 

[jaggedben]

This might work (as in, inverter turns on and outputs power), but it's the wrong way to go about it.

If you have a three phase service you want a three phase inverter these days. If the smallest 480V Solaredge inverter (30kW) can't be justified then I would go with the 208V 10kW inverter and a 480 to 208wye transformer. (Probably with a delta primary.)

Interconnecting a single phase inverter to just one phase of a three-phase 480V service is not so likely to receive utility approval. The transformer you have specified also appears to have a high-leg secondary which is ... unnecessary.

If it's going to be larger than one 10kW inverter I strongly advise filing the interconnection application before you build this one.

 

[jaggedben]

...
[*]is there a single phase to three phase Y transformer?

No.

 

[d0nut]

There are a lot of issues with what is shown.

1. There is not a single phase to three phase transformer. You would need a rotary phase converter or something similar to turn a single phase system into a three phase system.
2. You can put whatever size of fuse you want on the secondary of a transformer. You just have to size the conductors to match the fuse size. I would size the overcurrent protection at 125% of the rated current of your transformer secondary.
3. No. You need to bond the center of your Y to the ground conductor, not just pass the ground conductor straight through.
4. 4 wires plus the ground.

In addition, there is no such thing as a 240Y/120V electrical system. The vector math doesn't allow it. The transformer catalog looks to have an error as it calls out a delta primary and secondary, but also states there is a 480/277V secondary which would be a Y configuration. The transformer shown would be 240V, three phase delta on the primary and 480Y/277V on the secondary.

 

[Carultch]

In addition, there is no such thing as a 240Y/120V electrical system. The vector math doesn't allow it. The transformer catalog looks to have an error as it calls out a delta primary and secondary, but also states there is a 480/277V secondary which would be a Y configuration. The transformer shown would be 240V, three phase delta on the primary and 480Y/277V on the secondary.

It's probably built for either high leg 120/240V delta systems or corner-grounded 240V delta systems.