Oh yeah, price.
The rear end on the BMW is 37/11 or 3.36:1 so I'm similar to yours, but
I probably have larger diameter tires, 4.00 x 18. Maybe my current motor
has a whole lot less power than I though. Most of my commute is up
around 40-60 MPH so I would be in the 1700-2500 RPM range.
I think I would rather fit a fan than gear reduction IF the motor can
deal with the direct drive.
Good point about the motor not losing value; even if it loses some it's
a pretty cheap experiment overall. Probably should be doing that rather
than messing with this transmission. Oh well, I'm in the middle of
putting it in, so I'll probably cobble it together, take some data, and
see how it looks.
- Steve
damon henry wrote:
The only other downside is price...
The large one will handle more current better, but how much current do
you expect to need? It still might not be up to the task. I have run
mine at a 14 to 41 ratio which is about 3 to 1. IIRC you are in the 1
to 1 range. It takes at least 100 amps just to get me rolling, and
most of my riding is spent in the 100 to 200 amp range. I guess yours
will likely take 3 times as much. Mine only has 4 brushes, and while
you are correct that more brush area is better for higher amps, I
think even a 4 brush one will handle your amp requirements fine. The
biggest problem you will have is the heat. This style motor utilizes
an internal fan to keep it cool and at low RPMs this fan does not move
enough air. I have this problem when I drag my kids around in the
snow. I am running at very low speeds, with lots of extra drag which
heats my motor up quickly. The solution is that at the end of each
ride the kid gets to scoop up a big armful of snow and pack it on the
end of the motor.
A motors ability to deal with heat does have a lot to do with how much
copper is in it, so the 80 lbs motor will likely be able to deal with
about 30% more heat than the 60 lbs motor. I think even at this, if
you are pulling 100s of amps at less than 1000 rpms you will have
heating issues. If most of your riding is going to be done around
2000 rpms your probably fine with the larger motor directly coupled to
the shaft. One thing to remember about the motor is that it is not
going to lose any value, so if you try it and it doesn't work out, you
should easily be able to resale it.
On my truck I get away with a smaller motor (about the size of the one
you want) because I force extra air through it with a blower. I also
have a transmission. It works great, but trying to fit a blower on a
motorcycle is not much better than trying to fit a transmission on it.
It is unlikely that there is a perfect solution, but I still think
finding a way to let the motor spin faster is the best compromise.
Perhaps you can fit smaller wheels, or even find rim with a sprocket
to swap in the back. I know I have a couple of motorcycle junkyards
around me that make that kind of change pretty easy. If you take a
look at most fixed gear ratios on electrics I think you will see that
they are usually somewhere in the 3 or 4 to 1 range.
I first bought my motorcycle from a local add. I had no idea what I
was doing but wanted to do something. While I think I made a decent
choice, when I started looking for parts I found the motorcycle
junkyards. Once I found those, I couldn't help but think this is the
place where I should have started. They had a selection of rolling
chasis I could have compared to each other and chosen from.
damon
> Date: Wed, 26 Mar 2008 13:29:49 -0500
> From: [EMAIL PROTECTED]
> To: [email protected]
> Subject: Re: [ElectricMotorcycles] Hi-Torque Motors for sale
>
> The smaller ones are about the size of what I have now, but I imagine
> they have a lot more pull. I really would like to connect directly to
> the driveshaft, but that means pretty low RPMs at low speed and hence
> lots of current. The motor I have now doesn't like that. I'm thinking a
> larger motor, esp. with 8 brushes, would deal with that a lot better.
> And since I would need less than 2500 RPM max or so, I don't need to
> overvoltage it. What is the downside of a larger motor ( other than
> weight and size)?
>
> - SteveS
>
>
>
> damon henry wrote:
> > It will be great at lower volts. It likely has spent it's life up
> > until now running at 36 or 48 volts. When Jim says he has advanced it
> > to run at 72 to 120 volts what he means is that he has drilled and
> > tapped new holes and rotated the brush cap so to tune it to the
higher
> > voltage. It's just a matter of setting the cap back to it's original
> > position to optimize it for lower voltages and Jim would happlily
take
> > care of that little detail for you :-)
> >
> > That particular motor is as big as the one I have in my Datsun Truck.
> > It's definitely more than you need for a motorcycle. I have been
> > riding for years on a motor the size of the smaller ones he has
listed
> > with no problems. As long as your motorcycle is not super heavy you
> > should just snatch one of those up.
> >
> > Of course you will still have to work out the shaft drive thing.
> > Perhaps you can just work up some kind of jack shaft with sprockets
> > so you can try different gear ratios. It should take up less room
> > than a transmission and you will have more options as to where to
> > mount it. http://www.surpluscenter.com has a nice selection of
> > bearings, shafts, chains, and gears at very low prices. It makes
> > experimenting quite affordable.
> >
> > damon
> >
> > > Date: Wed, 26 Mar 2008 12:42:02 -0500
> > > From: [EMAIL PROTECTED]
> > > To: [email protected]
> > > Subject: Re: [ElectricMotorcycles] Hi-Torque Motors for sale
> > >
> > > Yeah, I've been drooling over them. Prices are much better than I
> > > thought they might be!
> > >
> > > The first one (DSCN2032) might be what I need for the BMW
conversion.
> > > Right now I'm in the middle of adding a transmission to it so I
can run
> > > more tests with my present motor, but the tranny really screws
up the
> > > layout and I really don't want it in the final setup. I wonder
how that
> > > motor would be at lower volts?
> > >
> > > - SteveS
> > >
> > >
> > > Damon henry wrote:
> > > > If you are in need of a good motor take a look at Jim's latest
> > > > offerings. Take my advice, don't screw around with one of
those easy
> > > > to melt pancake motors, get yourself one of these forklift
rebuilds
> > > > instead. Jim makes them bulletproof. They just soak up whatever
> > > > amps you throw at them and keep pushing you down the road.
> > > >
> > > >
> >
http://hitorqueelectric.com/gallery/v/MOTORS+FOR+SALE/rebuilt+modified/
> > > >
> > > > damon
> > > >
> > > >
> >
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> > > >
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> > >
> >
> >
> >
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