OCPD Brain Freeze!

[GoldDigger]

I understand.

So the 416:480 transformer is not a problem, even though uncommon?

And what about using three 240:480 1? xfmrs?

That will work just fine too, as long as you wire them to convert a 480 delta to a 240 wye, with corresponding phase shift/vector group.
More often they will be wired to convert a 480 delta to a 240 delta, which we do not need here, but either configuration is possible, depending on the result you are trying to achieve.

 

[Smart $]

That will work just fine too, as long as you wire them to convert a 480 delta to a 240 wye, with corresponding phase shift/vector group...

That'd amount to 416Y/240, which is why I suggested it in the first place.

 

[hurk27]

Why not simply feed every 3 inverters into a single core transformer with a 240 volt delta primary with a 277/480 or 120/208 Wye secondary depending upon what is needed?

 

[GoldDigger]

Possibly because the inverters have already been purchased and have a two wire 240V output?
And for a grid tied inverter which side of the transformer is the primary?


Tapatalk!

 

[hurk27]

That don't sound right. If you have a 240Y/132V system, the line-to-neutral voltage is 132V... not 240V. FWIW, I've not seen such a system... though I can see how the inverters could be that way on a standard 240/120 3? 4W system... but would you run the inverter's neutral to the panel (i.e. distribution panel, not AC combiner panel)?

Also, wouldn't the breaker then be based on 12kW/132V assuming the neutral point is grounded...???

actully it's 240/139v and very common to find this wire up on many generators and now a few transformers to allow a lower voltage grounding point insted of using a delta configuration.

sqrt3/240.748 is 139

 

[Smart $]

actully it's 240/139v and very common to find this wire up on many generators and now a few transformers to allow a lower voltage grounding point insted of using a delta configuration.

sqrt3/240.748 is 139

I was just quoting 132V value posted by GD. Didn't check accuracy... :happysad:

BTW & FWIW, the 240V is the standard... 139V would be the rounded value.

 

[Smart $]

Why not simply feed every 3 inverters into a single core transformer with a 240 volt delta primary with a 277/480 or 120/208 Wye secondary depending upon what is needed?

As noted by GD, two wire connection.

Needs one side grounded for GF reference.

 

[fossil112]

Possibly because the inverters have already been purchased and have a two wire 240V output?
And for a grid tied inverter which side of the transformer is the primary?


Tapatalk!

In my world, I see the energy flow *to* the grid as primary. So, 480 is our secondary with 416 as primary side (facing inverter).