6 Wire Open Delta

[tberry]

I am trying to come up with a source/method to 3 phase 6 wire open delta 115VAC 400HZ power to a product. My experience is more on the electronics side. I have access to 3PH 400Hz Wye power. How do you convert. Is is as simple as 3 1PH ISolation transformers?

 

[DanDel]

I'm not clear on your question. What is your load? 115V, 400Hz, I understand, but 3 phase, 6 wire open delta doesn't make sense to me. You can have 3 phase open delta, but that is a connection method for a 3 phase load from 2 phases of a 3 phase source. You say that you have access to 3 phase wye(this would mean 4 wire) 400Hz; what are the voltages of this system?

 

[tberry]

I may not be using the terminology correctly. The document I am reading the requirement from says "115VAC, 3-phase, 6-wire delta, 60Hz or 400 Hz Power". The power I have access to is 3ph 208 phase to phase, 115 phase to neutral. The load is a military power supply. I believe it may be as simple as using a 1:1 isolation transformer from each leg of the wye to neutral. THe input to the power supply has two line for each phase - ie Delta phase A, Delta phase A' etc.

 

[DanDel]

I've never heard of 3 phase 6 wire, since the phase relationships only require 3 connections. I've seen some monitoring equipment that uses two wires per phase, and typically the phases are jumped out so there is still only 3 wires needed for 3 phase. Your idea of using 3 single phase iso transformers should work. It will give you 120° and 120V between phases.

 

[busbar]

IEEE C57.12.70 §8 lists some six-phase "star" and "double-delta" configurations, but nothing "6ø open." Consultant/RFI time?

 

[jbartos]

Suggestion: Visit

http://www.fastron.com.au/pdf/f330-cat.pdf

etc. for more info on 6 wire open delta

 

[busbar]

tberry — The "6 Wire Open Delta" illustration on page 3 of jbartos' link

http://www.fastron.com.au/pdf/f330-cat.pdf

along with your description seems to point to flexibility in operating the device as either 200Y/115V 4-wire wye, or 115V 3-wire delta. The US military has used both, but I don’t know if 115V∆ configuration is still used. If this is indeed the case, the device MAY possibly be able to be powered by a 4-wire 208Y/120V circuit.