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Re: [EVDL] Gizmo EV "gearing"

Jeff,

I can't measure the diameter of the gear/pulley on the
motor since it is with the motor at Jim H's shop. I
was going to post pictures but I need a site to do so.
Nevco is out of business but Carl Watkins still
monitors email some so I sent him a message to see
what he could do. My Gizmo was a bit of a test bed for
things like regenerative braking so I don't know how
much different it was from other Gizmos. Because I was
having some intermittent troubles I was trying to find
I was able to secure the calibrator device for the
Sevcon controller so I can adjust things if needed.

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

>
> Hi David,
>
> You know, the 3 to 1 ratio doesn't sound right to
> me.
> Yes, counting teeth on the cogs should give you the
> ratio. Double check with the pitch diameters. Is
> it
> really 3 to 1? Were all Gizmos built with a 3 to 1?
>
> Or is yours some type of experiment? Mark said his
> was a 6 to 1. That sounds more reasonable. Can you
> get the 6 to 1 cogs from Gizmo? Are they still in
> business? And if you do, are you able to change the
> settings in the Sevcon?
>
> Jeff M
>
> --- "David D. Nelson" <[email protected]> wrote:
>
> > Thanks Cor,
> >
> > I wondered about that but after talking to D&D
> > motors
> > a few minutes ago I don't think I'll hit that hard
> > max
> > RPM. The guy I talked to said there shouldn't be a
> > hard max rpm, but then he didn't think I had a 3:1
> > gear ratio either. He didn't like my 30T drive
> gear
> > to
> > 90T wheel gear way of determining ratio. I told
> him
> > it
> > shouldn't matter since the same cogged belt had to
> > match up on both gears so the tooth pitch had
> better
> > be the same. Any way, he said that I should be
> > getting
> > to 4600rpm and 7ft-lbs of torque at the top end at
> > 48V.
> >
> > Below is the response I received from Mark Murphy,
> > after reading his reply I'm wondering if I should
> > add
> > one more 8V battery and see what happens. It looks
> > like the controller can be set to accept a
> slightly
> > higher voltage but I may be asking for trouble if
> I
> > do. The maximum cutout _low_ voltage setting is
> 48V
> > and the maximum cutoff _high_ voltage setting is
> > 75V.
> > Maybe if my DC-DC converter will handle 56V input
> it
> > would be worth a try. Any ideas?
> >
> >
> > --- Mark Murphy <[email protected]> wrote:
> >
> > > From: Mark Murphy <[email protected]>
> > > Subject: Re: Gizmo EV "gearing"
> > > Date: Mon, 27 Aug 2007 22:16:42 -0700
> > > To: "David D. Nelson" <[email protected]>
> > >
> > > Hi David,
> > > With the BugE we use a 5.5 ADC series wound
> motor
> > > with a 6-1 gear ratio
> > > ( on a 20" diameter wheel) My Gizmo is similarly
> > > geared using a ADC
> > > 6".6 series wound motor.
> > > Both are 48 volt.
> > >
> > > My experience is that you need a 24 volt rated
> > > series wound motor but
> > > run it on 48 volts.
> > > I don't think you need a larger motor,, you may
> > need
> > > lower gearing and
> > > higher RPM.
> > > if your motor is rated at 48 volts, run it at
> 72,
> > > but don't increase
> > > the weight of the battery pack.
> > >
> > > You can always install a fan for the motor.
> > >
> > > Belts are quiet, but usually require a lot of
> belt
> > > tension and pressure
> > > on the wheel and motor bearings. A chain is
> noisy
> > > but is low drag.
> > >
> > <<<<<snip>>>>>
> > ==========end of quote==========
> >
> > --- Cor van de Water <[email protected]> wrote:
> >
> > > Since the motor is SepEx, it will have a hard
> max
> > > RPM limit
> > > which depends on voltage.
> > > You can easily use a larger gear ratio to reduce
> > the
> > > torque
> > > (and thus amps) that the motor needs to sustain,
> > but
> > > the
> > > drawback is that you have to increase the
> voltage
> > to
> > > reach
> > > the same max speed, or accept that your max may
> > drop
> > > well below
> > > 40, likely even below 35.
> > > This can also be solved by rewinding the motor
> and
> > > keeping
> > > the same pack voltage - the choice is yours.
> > >
> > > Success,
> > >
> > > Cor van de Water
> > > -----Original Message-----
> > > David D. Nelson
> > > Sent: Monday, August 27, 2007 3:08 PM
> > > To: Electric Vehicle Discussion List
> > > Subject: 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.
> >
> === message truncated ===
>
>
>
>
>
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