RE: [CAD_CAM_EDM_DRO] Re: Re Power Supply

Although returning to the efficiency problem again.
Let's say that you need 50 volts at 20 amps to run the whole show.
That is 1,000 watts.
One horsepower equals about 745 watts.
This is at 100% efficiency.
Assuming a 50% efficiency for the alternator, you will need a spindle
motor that has about 2.7 extra horsepower to spare to power your drives.

I don't know about you but the spindle motor on my 6" South Bend lathe
is less than one horsepower. This would stall it.

If you cannot find a suitable transformer, consider my earlier post
about finding a busted Microwave Oven and salvaging the transformer from
that. They average around 1,000 watts and winding the secondary is
pretty simple.

Dave

> -----Original Message-----
> From: Mariss Freimanis [mailto:mariss92705@...]
> Sent: Friday, December 16, 2005 7:27 PM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: [CAD_CAM_EDM_DRO] Re: Re Power Supply
>
>
> Only a relatively small (10,000uF) cap is needed. Most alternators
> are 3-phase rectified. That limits ripple voltage to 13% with no cap
> if my trigonometry is correct.
>
> Mariss
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Roy J. Tellason"
> <rtellason@b...> wrote:
> >
> > On Friday 16 December 2005 06:35 am, roboticscnc wrote:
> > > Just a thought, has anyone used an old car alternator belt driven
> off
> > > the lathe spindle motor ? The cost would be virtually nothing and
> you
> > > could run 2 in series for 24 volts. The only dissadvantage I can
> see
> > > is that you couldn't test toolpaths without the spindle running.
> Would
> > > any other equipment be needed ( capacitor, etc. )
> >
> > You don't need two in series, particularly if you're dealing with
> the mopar
> > alternators that use an external regulator -- the output voltage is
> > completely controlled by what's done with the field winding, and
> can go
> > quite high, 24 volts not being a problem at all.
> >
> > Capacitor? Well, yeah, at least. The normal setup is for the
> battery
> > that's being charged to stabilize the voltage somewhat. You
> wouldn't need
> > that much of a battery to do so, but then you wouldn't want to
> overcharge
> > one continually either.
> >
> > There's a fair amount of stuff out there on the 'net in the
> alternate energy
> > context, a google search will surely return a lot of it.
> >
> > --
> > Member of the toughest, meanest, deadliest, most unrelenting -- and
> > ablest -- form of life in this section of space, a critter that can
> > be killed but can't be tamed. --Robert A. Heinlein, "The Puppet
> Masters"
> > -
> > Information is more dangerous than cannon to a society ruled by
> lies. --James
> > M Dakin
> >