[dorkbotpdx-blabber] 12 volt 20 amp power supply to drive a couple of pumps

[Dem Chi]

Ah, now that's very nice!

I love buying cheap stuff from harbor freight and using it as parts. That's
a good one. I'll look into it. Thanks

On Sun, Mar 15, 2009 at 9:53 PM, Eric Garner <garnere at gmail.com> wrote:

> LM3150 (http://www.national.com/pf/LM/LM3150.html) is a nice part in
> concert with some passives and two FETs. if you're just driving 12v
> motors, cheap battery chargers from harbor freight work a treat (at
> minimum they make great,cheap "donor" transformers).
>
> On Sun, Mar 15, 2009 at 7:50 PM, Dem Chi <dementedchihuahua at gmail.com>
> wrote:
> > Yes, the input source is the AC line. I'm trying to keep the component
> count
> > low. I need a 24Volt line at 0.4A. A 12V line at 20A and a 10V line for
> the
> > arduino. I really didn't want to have a bunch of transformers sitting
> around
> > in there if I could help it. The PC power supply idea is a good one. I
> guess
> > I could use a step-up transformer to get my 24Volt line off of
> that...hmm.
> > Besides, the transformers aren't all that cheap by themselves.
> >
> > I suppose it is a bit of power I'm trying to dissipate...bleh.
> >
> > Thanks for your response.
> >
> > On Sun, Mar 15, 2009 at 7:42 PM, John Luciani <jluciani at gmail.com>
> wrote:
> >>
> >> The problem is you need to drop too much voltage across your regulator.
> >> You
> >> will need to dissipate 240W (12V * 20A). You could parallel devices with
> >> diodes but it is still a lot of heat (just spread out a little more).
> >>
> >> You either need to get a transformer with a lower voltage output or use
> >> a DC-DC converter.
> >>
> >> Is the input power source the AC line (120VAC)? If it is the cheapest
> way
> >> to get
> >> 12V @ 20A would be a PC power supply.
> >>
> >> (* jcl *)
> >>
> >> On Sun, Mar 15, 2009 at 10:23 PM, Dem Chi <dementedchihuahua at gmail.com>
> >> wrote:
> >> >
> >> > Hi all,
> >> >
> >> > I'm making a power supply to drive two 12V 8amp DC motors. They are
> for
> >> > a
> >> > filtration box. They will be used both intermittently and sometimes
> for
> >> > long
> >> > durations. I've got a bridge rectifier from mouser rated for what the
> >> > transformer that I have outputs (621-GBJ20005-F). I'm getting a 24V
> line
> >> > at
> >> > ~20 amps. I need to take this down to a 12 volt line and current limit
> >> > it so
> >> > that I don't burn up my pumps. I am also taking off a 10 volt line for
> >> > an
> >> > Arduino but this is less important at this point.
> >> >
> >> > My problem is that voltage regulators that I've found--not many--that
> >> > can
> >> > take 24 volts and output 12 volts with 20 amps are expensive. Can
> anyone
> >> > suggest a circuit or IC or anything that will take the 24 volts I'm
> >> > giving
> >> > it and output a 12 volt 20 amp line?
> >> >
> >> > Priorities are cost and ease of construction. No surface mount parts
> or
> >> > anything like that.
> >> >
> >> > Any help is good help! Thanks
> >> > Stan
> >> > --
> >> > http://www.urbansurvivalists.com/
> >> >
> >> > _______________________________________________
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> >> >
> >>
> >>
> >>
> >> --
> >>
> >> You can't create open hardware with closed EDA tools.
> >>
> >> http://www.luciani.org
> >> _______________________________________________
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> >
> >
> >
> > --
> > http://www.urbansurvivalists.com/
> >
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>
>
> --
> --Eric
> _________________________________________
> Eric Garner
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