Re: MOT Power Supply Questions

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Stephen Conner by way of Terry Fritz <teslalist-at-qwest-dot-net>" <steve-at-scopeboy-dot-com>

At 07:46 02/04/03 -0700, you wrote:
>Original poster: "Simonas by way of Terry Fritz <teslalist-at-qwest-dot-net>" 
><rasim-at-takas.lt>
>
>
>maybe I've not explained it clearly:
>So now I have three pairs of
>MOTs providing each ~4kV AC.
>Question is, how to check relative phasing of them all before connecting
>whole thing to 3 ph. ?

The only thing that could go wrong, I suppose, is that you get one 'leg' of 
the star 180 deg out of phase. The DC output voltage would be very low in 
this case. You can check your finished transformer bank by hooking all 
three lines on the primary side together to the live of a single phase 
supply, and the primary star point to neutral. Put the three HV output 
wires close together (like a few millimeters). If the phasing is correct 
they should all be the same voltage and there will be no arcing. If you got 
the phasing wrong, there will be 8kV between one output and the other two, 
which will cause a very powerful bright arc.

 From what you wrote, it sounds like you are hacking into the 3-phase 
service entrance of the building where you live. This is extremely 
dangerous. You must get three high breaking capacity fuses for the primary 
side. I mean those giant industrial fuses that are about 3 inches long. 
Without adequate fuses, if your circuit shorted there could be an 
electrical flash/explosion that could seriously hurt you, not to mention 
blacking out the whole neighbourhood. Do a Google search for "electrical 
flash accident". Put those car booster cables down!

Steve C.