DIY Electric Car Forums banner

1 - 1 of 1 Posts

·
Registered
Joined
·
70 Posts
Discussion Starter · #1 ·
Re: [EVDL] Gizmo EV "gearing"

Thank you for all the ideas coming in on this.

I just sent Mark Murphy an email so I report back what
I hear from him. I have thought for a while that I
needed to figure out a way to do some forced cooling.
I am pushing this motor to its max when I climb. The
brushes showed evidence of arcing from the brush
holder to the sides of the brush. I don't know if this
happens only when the motor is hot (higher resistance)
or at any time. The armature current routinely goes
over 300amps during my hill climb.

David

--- keith vansickle <[email protected]>
wrote:

> 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]



____________________________________________________________________________________
Sick sense of humor? Visit Yahoo! TV's
Comedy with an Edge to see what's on, when.
http://tv.yahoo.com/collections/222

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
 
1 - 1 of 1 Posts
Top