3 Phase 208 to Single Phase 208

[janner_10]

European standardised voltage, including UK, is 230V + or - 10%. so 208 is the low end of acceptable voltages in the EU. ((230-208)/230 = 9.6%)

'Merica though, where voltages seem to be chosen with a bingo calling machine! No offence intended!

 

[JesperMP]

To the original question "OK to connect PSU rated for 3-phase 208V to single phase 208V".
Simply check the specifications of said PSUs. It is normally printed or labelled on the PSU itself what voltage range is acceptable.
The PSU will have 208V on two of its supply legs instead of on three legs. That is the difference. With only two legs supplying the power to the PSU, it can happen that its output is derated.

 

[Gene Bond]

240, 1ph also has 120v to ground on each leg... If not for the phase shift, they would be the same.

I wish our normal residential power here in the US was 208, 3ph, rather than 240v, 1ph. It would allow us to be a tad more efficient.

Unlike Europe, where their 240v is one leg of 380 to ground, with our 480 to ground we have 277v. Our 240v 1ph is a center-tapped leg of a delta transformer, which is not legal in a lot of countries.

Around the mid-west, especial in rural areas, we have a lot of 460v delta power as well, which is even worse. From a safety and noise filtering standpoint anyway.

My point is, depending on where your product is going, you should probably have a test rig with the proper transformer configuration to be able to ensure safety, filtering and functionality.

 

[rupej]

I wish our normal residential power here in the US was 208, 3ph, rather than 240v, 1ph. It would allow us to be a tad more efficient.

Not trying to argue, just curious why you say that. Are you saying that if the large loads like a heat pump was 3ph 208, the current draw per conductor would be a touch less and thus less power lost to heating the conductors?

 

[jraef]

Our 240v 1ph is a center-tapped leg of a delta transformer, which is not legal in a lot of countries

No, not true. It's a center tap, true, called a "split phase" off of 2 legs of what is, at SOME point up stream, a 3 phase distribution system. But the pole pigs in residential neighborhoods are rarely 3 phase. They are mostly single phase transformers usually with the primaries connected to one line and ground or maybe line to line on two phases, then the secondary is split in the center and referenced to ground as well.

Running 3 phases out to every residential neighborhood across this vast country would be ridiculously expensive. They can do it in other countries that have high density residential neighborhoods across much smaller geographies. But even then, they don't always bring all 3 phases into a house.

 

[Gene Bond]

Not trying to argue, just curious why you say that. Are you saying that if the large loads like a heat pump was 3ph 208, the current draw per conductor would be a touch less and thus less power lost to heating the conductors?

Just that single phase motors, are considerably less efficient, and shorter lived.

No, not true. It's a center tap, true, called a "split phase" off of 2 legs of what is, at SOME point up stream, a 3 phase distribution system.

That's my point. Other countries do not use Delta power. It's a bad idea to start with, and gets worse when you then try to use it for another purpose.