--- storm connors <
[email protected]> wrote:
> I live at the top of a 3 mile hill that requires 200
> amps to maintain 30
> mph. The 9 inch doesn't heat up at all. I keep it
> between 3 and 4000 RPM.
> Can't speak for lots of stop and start. But it would
> seem to me that you're
> not adding any more heat when you're stopped.
>
> On 10/11/07, Jeff Major <
[email protected]> wrote:
> >
> >
> > Lee,
> >
> > You make some good points. I'd add a couple.
> Like a
> > lot of stop and go driving. The accelerations
> demand
> > high current, but then you come to a stop. With
> just
> > the motor fan, you get heat soak and no cooling
> > sitting there. The external blower will continue
> to
> > cool the motor even at rest. And, perhaps the
> real
> > killer, hilly terrain. Going up hills can really
> heat
> > the motor up. And after doing a couple of hills,
> if
> > you don't have a good section of level or downhill
> > travel, the motor fan isn't going to do a lot for
> you.
> >
> > I think I mentioned before, I'm a big fan of
> forced
> > ventilation. Especially now that better batteries
> are
> > becoming available. I think in a lot of cases,
> with
> > Pb-acid, by the time the motor was too hot, the
> > battery would be dead. Now, if you have the same
> > system with a battery which can run 2, 3 or 4
> times
> > longer, maybe the motor will not survive.
> >
> > Jeff M
> >
> >
> >
> > --- Lee Hart <
[email protected]> wrote:
> >
> > > From: Bob Rice
> > > > All this cooling bahoura, with the 9 inch
> motors!
> > > My 8 years of driving
> > > > a ADV 9" rebuilt by Warfield Electric; Never
> an
> > > issue with cooling! ...
> > >
> > > If you drive with the motor at high RPM most of
> the
> > > time, then its internal fan does a fine job. I
> don't
> > > have an external blower on my EV either.
> > >
> > > However, many first-time EVers (and even some
> old
> > > timers) drive as if the electric motor were an
> ICE
> > > -- they try to shift to keep it at low RPM. This
> has
> > > the consequence of making the motor draw more
> > > current, so it makes more heat. It also gets
> less
> > > cooling air, so it runs too hot.
> > >
> > > Another problem occurs with direct drive EVs,
> where
> > > there is no transmission. Here, you can't shift
> to
> > > make the motor's internal fan work at low
> driving
> > > speeds.
> > >
> > > Finally, some people are using undersized motor
> to
> > > save money, or simply for the sake of
> expediency.
> > >
> > > If any of these cases apply, an external blower
> > > helps a lot!
> > >
> > > --
> > > "Excellence does not require perfection." --
> Henry
> > > James
> > > --
> > > Lee A. Hart, 814 8th Ave N, Sartell MN 56377,
> > > leeahart-at-earthlink.net
> >
____________________________________________________________________________________
Check out the hottest 2008 models today at Yahoo! Autos.
http://autos.yahoo.com/new_cars.html
_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev