Hmmm, interesting, and I WOULD tell Jim if I were you because something does not sound right. I do not think your brushes should be getting that hot. You may find out that you still have a problem after you change the drive setup. This may actually be a motor setup thing. Did Jim advance the timing for you? Are you sure that the rotation is the right direction? I only have a 4 brush motor and have run mine with a 400 amp Alltrax without ever having those type of issues. Anyway, it sounds like you are already heading a different direction, but I would still be a little worried that something is not right with your motor setup. I would expect to be able to drop your motor onto my bike with my front sprocket and run it all over without any heating issues. Your motor sounds a little bigger and beefier than mine, and mine has proven to be well up to the task. damon
> Date: Sun, 2 Nov 2008 21:20:45 -0500> From: [EMAIL PROTECTED]> To: > listserv@electricmotorcycles.net> Subject: Re: [ElectricMotorcycles] BMW > update> > 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® > 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> >> > > > > _________________________________________________________________ Store, manage and share up to 5GB with Windows Live SkyDrive. http://skydrive.live.com/welcome.aspx?provision=1?ocid=TXT_TAGLM_WL_skydrive_102008
