Curious: bi-phase vs. 2-phase charging?

5460 Views 5 Replies 4 Participants Last post by hvacman, Nov 18, 2016

Sean_R

Discussion Starter · Nov 18, 2016

Does anyone happen to know if 208 VAC 2-phase charging is supported on the Volt, rather than 240 VAC bi-phase? Just curious if this is specified either on the Volt, or perhaps with the J1772 standard.

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hvacman

· #6 · Nov 18, 2016

Qinsp said:
A commercial building has a WYE transformer for it's 120vac 1ph power. It has 4 wires going out:

L1 - Hot 120v
L2 - Hot 120v
L3 - Hot 120v
White - Neutral for 120v

Any two of the L1, L2, or L3 lines when hooked to power leads makes 208vac, not 120v. Why? They are 120° separation. Only when they run a 3 phase motor do they kick out 240v.

You do not use the Neutral on a 208 circuit. You would use a second Hot instead.

120/208 "wye" is the current "standard" way of getting 3 phase and 120 volts 1 phase out of a single service, but there are also lot of 120/240 "high-leg delta" 3 phase systems out there which work differently.

https://en.wikipedia.org/wiki/High-leg_delta

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