[jgs8919]

How can one change an incoming 240V, 4wire to 120/208V WYE?

 

[Big John]

Buy a 240VΔ:208Y transformer...? There's no shortcut that I know of.

 

[micromind]

Or get the POCO to change their transformers.

 

[That_Dude]

How can one change an incoming 240V, 4wire to 120/208V WYE?

Is it 120/240 Single phase or high leg delta? More information will help you here.

 

[Pharon]

If it's 240 volt, 4 wire, that sounds like 3 phase...

 

[micromind]

Yep, my guess too.

It's possible to lower the voltage and create a grounded wye using buck/boost transformers, but the ∆ system would need to be ungrounded.

 

[jgs8919]

Or get the POCO to change their transformers.

How difficult is that? I am assuming also expensive..

 

[jgs8919]

Is it 120/240 Single phase or high leg delta? More information will help you here.

A high leg delta. The way it is wired...one of the phases is unused and the other two are feeding a single phase subpanel. We want to install a PV system. So we want to know whether there is a cost effective way of changing the voltage configuration without having to install 3 single phase inverters.

 

[That_Dude]

https://www.swgr.com/store/dry-type-low-transformer/product/11-4388.aspx Might help.

 

[Pharon]

A high leg delta. The way it is wired...one of the phases is unused and the other two are feeding a single phase subpanel. We want to install a PV system. So we want to know whether there is a cost effective way of changing the voltage configuration without having to install 3 single phase inverters.

Check the listing of your 208 volt inverter. If it's good for 208 volts, it should be good for 240 volts -- since it's less overall current. And all the insulation ratings should be good for 250 volts anyway.

If not, then three 1-phase inverters will probably be cheaper than putting in a 208-240 volt, 3 phase transformer.

What's the kVA rating and manufacturer name of the inverter?

 

[jgs8919]

Is it 120/240 Single phase or high leg delta? More information will help you here.

Check the listing of your 208 volt inverter. If it's good for 208 volts, it should be good for 240 volts -- since it's less overall current. And all the insulation ratings should be good for 250 volts anyway.

If not, then three 1-phase inverters will probably be cheaper than putting in a 208-240 volt, 3 phase transformer.

What's the kVA rating and manufacturer name of the inverter?

It is a small system. 13.08kW system and the inverter is:
http://www.svssolutions.com/wp-content/uploads/2012/08/SPR-10001f-1-UNI-SPR-11401f-1-UNI.pdf

 

[jgs8919]

It is a small system. 13.08kW system and the inverter is:
http://www.svssolutions.com/wp-content/uploads/2012/08/SPR-10001f-1-UNI-SPR-11401f-1-UNI.pdf

Sorry wrong link.
Inverter is: http://www.svssolutions.com/wp-content/uploads/2012/08/SPR-11401f-3-208-240-DELTA.pdf

 

[Pharon]

Both of those links are getting flagged for me as malware. But if you can open and view them, it should be self-explanatory. Or, just call the manufacturer and ask to speak with one of their technical support people. I'm sure they will be able to answer your question.

 

[micromind]

How difficult is that? I am assuming also expensive..

Around here, the POCO will swap a delta bank for a wye at no cost. They're trying to get rid of deltas, especially pad-mount.

If they're pole-mount and all 3 are the same size, they'll simply re-connect then internally and re-connect the service drop to a wye.

 

[jgs8919]

Thank you for all the advice everyone. The inverter manufacturer confirmed that I can just connect them to the three lines without pulling a neutral.