Re: Production EVs

[Joseph F Klein <jklein@hpower.com>]

The Park pawl in an automatic is a cog type gear, with a bar engaging a cog to
"Lock" the transmission while it is neutral. It will take a few seconds for park
to grab, during which there will be some very hidious noises from the
transmission, followed by ALOT of excitement (never a good thing), skidding, and
alot of various metal parts on the road and loose in the transmission (assuming
that your drive line stays where you put it last).
  If you have a "Park" then you have a "NEUTRAL", USE IT ! Through the thing into
neutral, stop the vehical, then do whatever you have to to shut off the power.
  When i worked For the New York City Transit authority, they're 600  DC volt
all-the-amps-God-and-ConEd-could-supply Subway cars, they had a main contractor
that would bull in with the closing of the dead mans switch. They also had an
electronic circuit that would moniter the current draw. If the current draw was to
high, the contactor would drop out and stay dropped out until repaired. The
typical cause was either a welded switch (the controllers are basically three
speed controllers),  a shorted resistor, or a shorted motor. One motor on a car (4
per car) on a ten car train could make life exciting.

Joe Klein
H-Power Corp.
Process Technologist






























LEE A HART wrote:

> Bill Dube' wrote:
> > failing randomly at full throttle is much more dangerous
> > than failing randomly with locked (or at least skidding) tires.
>
> This a false either/or choice; like asking whether it is better to be shot or
> stabbed. You don't have to choose between them. Both are bad. Both can be
> addressed separately.
>
> Having the car suddenly lunge forward when a child is crossing in front is
> bad. Having the wheels lock on the freeway at 60 mph is bad. You don't compare
> them, and pick one; you design the vehicle so NEITHER ONE will happen.
>
> George Tylinski wrote:
> > the parking brake ought to be on and in peak condition to
> > reduce the damage in the DC-fails-short scenario.
>
> The parking brake is only there to keep the car from rolling away on an
> incline, or wandering off if the wind. My ComutaVan will easily blow away if I
> forget to set the parking brake)!
>
> Believe me, there is no chance that any parking brake will stop an EV from
> driving off if the controller fails "on" (whether it is AC or DC)!
>
> I don't know if "park" on an automatic is strong enough to stop it or not.
> Anybody done some field tests?
>
> Lee Hart                     If you would not be forgotten
> 4209 France Ave. N.          Soon as you are dead and rotten
> Robbinsdale, MN 55422 USA    Either write things worth the reading
> phone (612) 533-3226         Or do things worthy of the writing
> e-mail XURQ03A@prodigy.com   (Ben Franklin, Poor Richard's Almanac)