Ian King (IanK at
vulcan.com) wrote:
We *are* running the machine off three separate 110V single-phase
circuits
-
apparently you missed that part.
People need to understand the danger in this - in any multiphase
power
system, the neutral current is the DIFFERENCE of the current in the
individual phases. If the load is perfectly balanced, then the
neutral
current will be zero.
But, if you run the same load from three separate single phase
circuits
and (worst case) the three circuits are all the same phase, then the
neutral
current will be the SUM of all three phase currents. That's 3 times
what it
would be otherwise and runs a serious danger of melting the neutral
and
starting a fire.
I agree with all but the last bit, because if he's running it from
three separate supplies, surely he will have three neutral conductors,
so no problem.
Roger Holmes
(Who has a 440v three phase computer drawing 13kVA which has three
phase bridge rectifiers to generate fairly ripple free DC)