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Re: [EVDL] Gizmo EV "gearing"

david
have you emailed Mark Murphy at Blue sky design he is
in creswell oregon and originally built these veh
kEVs

--- Jeff Major <[email protected]> wrote:

>
> Hi David,
>
> You might want to consider forced ventilation on the
> motor. Sounds like your performance is O.K. Just
> that your duty cycle is too hard.
>
> Increasing the gear ratio will lower the load on the
> motor and slow down the top speed of the vehicle.
> That would likely make the motor run cooler, but
> take
> you longer to get where you're going. I'd try
> keeping
> the same ratio and blowing a lot of clean air thru
> the
> motor.
>
> Regarding the larger motor, you'd probably have to
> retune the controller.
>
> Jeff M
>
>
>
>
> --- "David D. Nelson" <[email protected]> wrote:
>
> > Hi all,
> >
> > I have a Gizmo EV (www.nevco-ev.com) which has a
> 48V
> > pack and a 6.7" D&D Separately Excited Motor. I
> have
> > run it for a year but the hill climbing I have to
> do
> > has started to burn up the motor. Jim H has it
> right
> > now to rebuild/repair. We had been considering
> > installing a 7.5" motor to see if it would handle
> > the
> > workout I give it a little better.
> >
> > I decided to do some calculations to see what rpm
> > the
> > motor was spinning and here is what I found:
> >
> > Speed : tire rpm : motor rpm
> > 10 : 171 : 514
> > 20 : 343 : 1029
> > 30 : 514 : 1543
> > 40 : 686 : 2057
> > 50 : 857 : 2572
> >
> > What I am wondering is if I can change the gearing
> > to
> > get a better than a 3:1 ratio maybe a 6:1 ratio
> will
> > I
> > still have the same top speed? Right now my top
> > speed
> > on the level is about 44mph. Jim, and I think he
> > said
> > Tim, thought that maybe the existing motor would
> > handle my needs if the motor spun at a much
> higher
> > rpm.
> >
> > My next question is, does any one have any
> > suggestion
> > as to where I might find some replacement
> > gear/pulleys? This is a belt driven vehicle which
> > has
> > the "teeth" in a V shape like this:
> >
> > \\\\\\
> > //////
> >
> > including the gap in the middle. The belt is a
> > GoodYear Eagle W-1280. I also need to know what
> the
> > smallest drive gear I can safely use. The current
> > one
> > is 30 teeth. The one on the drive wheel is 90
> Teeth.
> >
> > I have attached 3 pictures. (I hope this doesn't
> > violate list rules.) It appears that there are two
> > sets of bolts which bolt the gear/pulley on the
> > wheel.
> > One set bolts to the wheel hub, then there is an
> > aluminum adapter which then bolts to the gear it
> > self.
> > There isn't much room to go larger with the
> wheel's
> > gear since the belt would interfere with a
> support.
> > I
> > think I could go to a 115 tooth at the wheel so if
> I
> > could go as small as a 20 tooth drive it would be
> at
> > a
> > 5.75:1 ratio.
> >
> >
> >
> >
> >
> > David D. Nelson
> > [email protected]
> >
> >
>
>
>
>
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