Re: [CAD_CAM_EDM_DRO] Re: Home shop power for a big machine

>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com
> <mailto:CAD_CAM_EDM_DRO%40yahoogroups.com>, "vrsculptor" <vrsculptor@...>
> wrote:
> >
> > I was lusting over a big VMC that would never fit in my home shop and
> > got to wondering about power. The machine's data plate says 230 volts
> > 3PH @ 80 AMP's, 18KVA. It has a 15 HP spindle.
> >
> > I could use a rotary phase converter to generate the three phase but
> > don't have anywhere near 80 AMP's available. 18KVA/750 watts equals a
> > 24 HP phase converter.
> >
> > If you where using this machine in a hobby environment and not trying
> > to get production feeds and loads how small of a phase converter could
> > you get by with?
> >
> > Roger
> >
> one trick is to use "idler" motors to help generate more 3Phase. If
> you can build a rotary converter that will start a 5hp 3phase motor
> spinning then you can start and run an 8-10Hp load. Once you have
> that running you can start and run a 15 or 20 horsepower load, etc.
> Each 3P motor running without a load on the circuit adds back in power
> for the 3rd phase. It's not a net gain (be cool if it was beacuse
> then your electricity would be Free (:-) and you need enough front end
> watts on the 2 phase to keep all the motors turning but it is one way
> to build a lower cost rotary converter for big equipment. You can
> find surplus 3 phase motors pretty cheap. There are some good
> articles on building your own 3P rotary converter.
>
> __._,_.