480V to 240V

[wwhitney]

My understanding is if the 2 phase loads are balanced it does produce a balanced 3 phase load.

OK, I went through the math and you are correct, the Scott-T will produce a balanced loading on the 3 phase supply from a balanced loading on the 2 phase secondary.

I think the current carrying capacity of the coils in the Scott-T transformer is used less efficiently than in a hexaphase arrangement, as in the Scott-T the primary coil with the center-tap has to carry out-of-phase currents even for purely resistive loads. I.e. say you are starting with split-primary/split secondary single phase transformers, which also have a 86.6% tap on the primary side, and you are considering building a Scott-T from them, or a hexaphase arrangemen. Then for a given kVA nameplate of transformers, the hexaphase will give you the full kVA available on the secondary, while the Scott-T will give you less.

Cheers, Wayne

 

[tortuga]

It sounds fun, I can see it now 'Winny & Whitney transformers Co. Hexaphase transformers r us.'
Well in any case we verred off topic again
-> never use a transformer with a resistance waterheater, just get the correct elements for the voltage you have. <-
and by all means look into those new heatpump waterheaters if your on electric resistance.

 

[ggunn]

He is ordering a direct replacement 3Ø WH.

Without knowing anything else about the situation, that seems reasonable. Whatever savings there would be in getting the single phase heater would most likely be eaten by the cost of the transformer and wire.