400 Volt Single Phase Welder

mikeohms · Feb 28, 2009

it is a bit more complicated than that if you look at sinusidal wave and who voltage is derive you have maximum and minimum but your voltage at any point in time is derived from only one of your phase cable not two that is why its called single phase.
you can not have two phase supply because you always need one cable to act as a return part i.e. neutral
you can not have a load without a neutral part
Phase means supply or input not return or neutral although you can see two phase cable comming in but in reality only on is for supply the other is neutal
Trust me on this
thanks

Guest123 · Feb 28, 2009

I'm sorry but technically it is 2 phases because as you said one is only acting as neutral, and it isn't earth so that only leaves phase, and as they are 120' apart on the wavefrom then yes I agree one is the return path, but it is phase.

mikeohms · Feb 28, 2009

but it can not be a return path and phase at any point in time so you can not call the two cable supply or phase cables because at any point in time one is supply and the other is neutral.
You can suggest a better way of calling them, as long as you know that is what its technically call for the time being

Guest123 · Feb 28, 2009

I completely agree with what your saying and technically the same can be said for purely balanced 3 phase supplies also as they are all at 120' angles to one another which is why no seperate neutral is needed.

I feel that some terminology not just in this instance but on various others is confusing/misleading to people who dont have the knowledge, take this welder as a prime example - it's being sold on the internet to anyone who wishes to buy it but described as single phase which to anyone else means just that L,N+E

Thanks.