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Re: 3-phase current - you don't need caps or ider motors!
Bert and all,
Keep in mind that the typical 240 volt feed to our houses in the USA is
really two 120 volt lines 180 degrees out of phase, so no amount of
transforming alone will ever get you three phases 120 degrees apart. The
scheme you posted will only work if the original two phases are 120 degrees
apart.
Someone else posted the idea of using a single phase motor driving a three
phase motor running as an alternator. There is a way to put large
capacitors across the motor windings to make it act as an alternator. It
is originally excited by residual magnetism to make the output voltage
build up. But as I recall this scheme is only useful for driving loads
which are mostly resistive--probably not very good for running a TC NST or
pig.
--Steve
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> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: 3-phase current - you don't need caps or ider motors!
> Date: Wednesday, December 09, 1998 11:48 AM
>
> Original Poster: bertpool-at-ticnet-dot-com
>
> Date forwarded: Tue, 8 Dec 1998 14:01:11 -0700
> Date sent: Tue, 08 Dec 1998 12:05:12 -0700
> To: tesla-at-pupman-dot-com
> Subject: Re: 3-phase current
> Forwarded by: tesla-at-pupman-dot-com
> From: Tesla List <tesla-at-pupman-dot-com>
><SNIP>
> I knew I had this somewhere, but it took me a while to find it. There is
a
> way
> to change 2 phase power to 3 phase using only two transformers! It is
> called a Scott transformer, and was used by power companies to go from 2
> phase to 3 phase or 3 phase to 2 phase power. You do not have the puny
> power limitations of capacitor systems, nor do you have to use a large
> motor/generator setup. I found this in my 1939 Coyne home electrial
> course. One transformer is centertapped, the other transformer has a tap
> placed at the 86.6% point. I will place the schematic and text on my web
> page in the next day or two and I will notify the list when it's there.
> This is
> such a handy thing for high-power coilers to know how to do.
>
> Bert Pool
>
>
>