Hi Mark, How quiet is it compared to the typical chain drive? Have you measured amps with the rear wheel in the air (e.g. center stand)?
- Mike B 1994 Kawasaki Ninja -----Original Message----- From: Mark Eidson <[EMAIL PROTECTED]> To: ElectricMotorcycles <listserv@electricmotorcycles.net> Sent: Sun, 2 Nov 2008 9:13 pm Subject: Re: [ElectricMotorcycles] BMW update I have a 4.74:1 total drive ration between the motor and wheel and top out at 52MPH at about 3000rpm with a 72V pack. http://www.evalbum.com/preview.php?vid=1231 My motor is a 6.7" with 8 brushes. My belt drive components are from McMaster-Carr. http://www.mcmaster.com/ I really designed my drive ratio for 96 volts but only put in 72.......to save weight and cost. 52MPH is fine for me. Acceleration is very good. No overheating even in AZ when it is 120F. On Sun, Nov 2, 2008 at 7:20 PM, SteveS <[EMAIL PROTECTED]> wrote: > Like starting to smoke hot (don't tell Jim!). Right from the brushes - > actually one set I think. Could be they aren't set yet as the motor had just > been rebuilt. All the brush holders were fairly hot to the touch. The motor > housing was cool. I should have run the brushes in with no load. > > I didn't measure amps - left my Palm with the Alltrax software at work, but > I bet I was pulling over 300 motor amps. > > I know riding around slow in the yard on grass (the bike) is probably worse > case, but I really would like a bit more low end. My problem is I have to > climb a gravel driveway when I get home, so I need decent low speed power at > a lower SOC on the battery. > > I know you run a lower ratio too Damon, though I think my rear tire is > bigger - 19". I calculated I get 2.33 MPH/100 RPM. That gives me 63MPH at > 2700 RPM, so I really can afford a higher gear ratio, as I really don't need > to go over 50 or 55. The bike seems to roll easily. I did some pull tests > with a spring scale on a flat concrete floor and it pulled easily (I forget > the value...). > > In any case, I already tore it down and started planning out how to run a > chain reduction to the drive shaft. Actually I think it'll be a better setup > physically. Just have a bit of chain noise. BTW is there a source for drive > belts? I would think that would be quieter. Since it's before the final > 3.36:1 ratio it doesn't have to as beefy as a final drive belt would be - > more like a primary belt (if anyone uses them there). I don't know much > about chain and belt drives having owned shaft drives for so long now. > > Anyway, I was grinning a bit! > > - SteveS > > damon henry wrote: >> >> I would not give up on the shaft drive just yet. What do you define as >> hot? It's likely that the insulation in your motor is rated up to 180 deg >> Celsius. Try measuring the brushes with a temperature probe after you heat >> things up. How many amps were you pushing through the motor? More amps will >> give you better acceleration (and make things heat up even quicker). And >> finally, what speeds will you be doing most of your riding at, what kind of >> RPMs will your motor usually be turning, and how often will you be riding up >> hill? Lugging the motor at low speed around home will heat things up because >> there is no air flow being generated by the internal fan in the motor. >> Pulling the same amps to maintain a higher speed, the motor will run cooler >> because of the higher RPMs. >> >> I have been running my motorcycle for years with a chain and a 14 tooth >> (now 13) front sprocket and a 41 tooth rear. That overall ratio sounds to me >> like it is close to what your shaft drive setup provides... unless I am >> reading your ratio backwards. >> >> Having said all that, I can ride my motorcycle around all day long at low >> speed without any heating issues at all. The times that my motor has been >> the hottest has been in the snow when I have used it to drag the kids around >> the cul-de-sac on a sled at very lows speeds. That's easily remedied by a >> well placed armful of snow, but the extra drag of towing the kids really >> heats things up. How well does your motorcycle roll? >> >> damon >> >> >> >> >> ------------------------------------------------------------------------ >> >> > Date: Sun, 2 Nov 2008 08:26:43 -0500 >> > From: [EMAIL PROTECTED] >> > To: listserv@electricmotorcycles.net >> > Subject: [ElectricMotorcycles] BMW update >> > >> > Another milestone (of sorts) in my BMW motorcycle conversion journey. I >> > had played around with an Elec-Trak motor direct to the shaft drive, >> > which proved woefully inadequate. From taking with several people it >> > seemed that I really needed to go to a higher gear ratio (the 'built-in' >> > ratio is 3.3:1); or, possibly, a bigger motor. Jim Husted found a nice >> > 7", 8-brush, motor for me. I thought I'd try it direct just to see, >> > which I did yesterday. It did pull away (slowly) from a stop and >> > actually had ok acceleration, but the brushes got hot from my low speed >> > driving around the yard. >> > >> > So I guess I'm finally convinced I need to add a gear reduction. I had >> > hoped to use a planetary gearset, but really couldn't find anything >> > appropriate, so it looks like chain and sprockets. Now I have my winter >> > project. >> > >> > Too bad, as the direct drive was absolutely quite; really sweet. >> > >> > - SteveS >> > >> >> >> ------------------------------------------------------------------------ >> When your life is on the go—take your life with you. Try Windows Mobile(R) >> today <http://clk.atdmt.com/MRT/go/115298558/direct/01/> >> ------------------------------------------------------------------------ >> >> >> No virus found in this incoming message. >> Checked by AVG - http://www.avg.com Version: 8.0.175 / Virus Database: >> 270.8.5/1762 - Release Date: 11/2/2008 9:51 AM >> >> > > > >
