Date:         Wed, 19 Apr 2000 00:37:05 -0400
Reply-To:     ed <edevinney@BIGFOOT.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         ed <edevinney@BIGFOOT.COM>
Organization: Pismo Beach Institute for Advanced Leisure Studies
Subject:      Re: A/C compressor Power usage
Content-Type: text/plain; charset=us-ascii; x-mac-type="54455854";
              x-mac-creator="4D4F5353"

Even if it were possible, is it that this solution (driving the van's compressor on
alternating current) is to the wrong problem?  IIRC, didn't Todd just buy a Westy
with an owner-installed re-packaged home AC unit under the rear seat?  Yeah, it
takes up valuable storage space, but that 10hp motor can't be much smaller :-)  A
new window shaker unit is almost surely quieter and more efficient than the 16+
year old design in our vanagons.

ed

Jim wrote:

> Wow, an off-the-wall question that I have experience with!!!  We have a
> stationary crane where I work.  It has an automotive a/c unit run by an
> electric motor.  It is geared 2:1 (2 turns of the motor to 1 turn of the
> compressor)  We use a 1725 rpm motor. I currently has a 5 hp 3 phase motor on
> it and come summer, it will, no doubt burn up yet another motor.  This year
> I'll up the hp in hopes of precluding another melt down to a 10 hp motor.  A
> 10 hp THREE PHASE 480v motor draws about 20 amps. (Guessing... the NEC* is at
> work.)  AFAIK they don't even make a 120v 10 hp motor.  If they did, it would
> draw about 80 amps.  That's a lotta juice, my friend.  Not really practical.
>
> Wait, I just found the 1999 NEC*...  10hp single phase, 120v motor draws 100
> amps.  That's 4 ga. wire to feed it.  About the size of your jumper cables.
> Definitely more than your local campground will have available.
>
> Jim
>
> * National Electrical Code
>
> > Folks,
> >  We are planning a 3 week x-country camping trip this summer. Although we will
> > not be camping with access to power most of the time, it would be nice to have
> > the option of A/C at night if it is really hot out.
> >
> >   Not wanting to lug around a household A/C unit or install an oversize R/V
> > unit, I thought, why not use the existing refrigerant loop?
> >
> >   - Add second clutch to Compressor with belt to A/C motor
> >     (or some other means to power the compressor off
> >      another source)
> >   - Add control electronics
> >     - Interior Air temp sense
> >     - Evaporator fan control (interior fan)
> >     - Temp sense of Condensor and Fan speed control to
> >       reduce noise emissions
> >     - Control of A/C motor
> >     - Safety sense (Low press. sensor,etc..)
> >     - battery charger to maintain charge with all the
> >       12V fans running
> >     - etc..
> >
> > Questions:
> >     - How much power does the A/C compressor use?
> >     - What is the most efficient speed (RPM) for
> >       compressor operation?
> >
> > Just an idea.... Opinions?
> > Thanks,
> >  Ezra
> > '88 Westy
> > '86 944