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Re: [EVDL] Gizmo EV "gearing"

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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