Three phase to single phase question.

[Sleken]

Hello all. I have a customer that wants to install some mini-split air conditioners. Apparently, they can only be purchased in single phase 208-240 volt configurations. I need 62 amps on the secondary.

The customer has three phase 277/480 available with a 30 amp fusible bucket currently spared in the switchboard.

Hubbell-Acme Electric (Is Hubbell buying everything?!) says this isn't possible without a custom transformer.

This doesn't seem correct to me, but my experience is only with stepping down three phase to another three phase voltage.

Does anyone have any thoughts?

--Josh

 

[GoldDigger]

Step down to 208Y/120 with a standard transformer and then balance the mini-splits across the three available L-L 208V circuits. The mini-splits should not care that the 208 is 2 out of 3 derived from three phase.

Sent from my XT1585 using Tapatalk

 

[Smart $]

How are you calculating the 62A? If you are arithmetically summing the MCA's of several 1Ø units, that will not be correct for several units balanced on a three phase source.