Noted, that's why I used a 415/240V rather than a 208/120V system in my example.supersparks said:dont forget, this isnt the US,
The only way to balance the load perfectly would be to hook up only three-phase devices, such as three phase motors and three phase electric heaters. In these cases the phases can't help but balance (assuming the product was designed well) and you don't have to worry about it.supersparks said:i cant realy see that there would be much difference, but i have seen 3 phase alone, with no neutral, and there has been no tranny.
...i always thaught that the idea was that you balance the load perfectly on the phases, so there is no current for the neutral to compensate, so is not needed......
When using single-phase devices, all you can do is balance it as best you can and live with the neutral current you will inevitably have left over. For this you usually need a star-connected transformer feeding the system, although I have seen center-tapped grounded deltas (but not for this type of application).
Do you mean what do you do with the neutral connections on the device you are hooking up to the three-phase system? You don't want to hook up a single-phase device across two phases of a three-phase system, they usually require the neutral conductor to be grounded, and this obviously isn't an option if you're using two live phases. Also don't forget that phase-to-phase you'll be getting 415V, not 240V (line-to-line = line-to-neutral x 1.73).supersparks said:whilst i think about it ne thing i dont understand is; what do you do with the neutrals from the fittings? do you connect across phases instead of phase-neutral
If we're still under the assumption that we don't have a neutral available, what we'll want to do in this case is hook up a delta-to-star transformer and use the neutral from the star side as the return path for each phase that is powering computers.
Another thing, you don't want hook up a computer to an ungrounded delta system anyway. It's floating with respect to the building ground and the power supply won't like that. A star connection is definitely the way to go here.