Re: [ElectricMotorcycles] " Motor Load and DriveLine Losses - Observations and Questions" ListServ Digest, Vol 18, Issue 12
what Kevin said Plus You can get an idea of the power train losses by comparing rear-wheel horsepower and engine horsepower numbers. Unfortunately this is rule-of-thumb stuff because neither number is particularly accurate or repeatable, especially once the marketing department or racer's ego massages it. But, everyone agrees there is a difference, and its on the order of 10-20 hp as reported in the more reputable magazines, sometimes more. You can easily prove that the drag is nearly all in the transmission by spinning the rear wheel with your hand with the bike in neutral. So *I* wouldn't mess with the belt, unless there is an off-the-shelf solution. Even then its going to cost more than a chain. Belts sometimes suffer from damage too. Millions of people ride with chains with very little maintenance. Basically keep it slack and clean it once in a while and apply whatever lube is recommended. Harley racers usually convert to chain drive BTW, and its not only to get better control of gearing. This makes me realize there is a considerable benefit on an EV bike to running without a transmission. You'd have to give up the belt for sure, but sprockets are cheap and plentiful so you can try a few until you get the ratio just right. Can you get those motors to run in a wide enough rpm range to do that? John Kevin Caldwell wrote: Both chain drives and belt drives can be 95%+ efficient, but both must be adjusted and aligned properly. O-ring chains that most street bikes will have as stock these days will consume more power than a non o-ring chain. It is much easier to change ratios with a chain drive. Chain drives require some slack, and the losses will be high if they are too tight. There is not really any power lost because of the chain slack, at least until it starts jumping teeth.
Re: [ElectricMotorcycles] " Motor Load and DriveLine Losses - Observations and Questions" ListServ Digest, Vol 18, Issue 12
Both chain drives and belt drives can be 95%+ efficient, but both must be adjusted and aligned properly. O-ring chains that most street bikes will have as stock these days will consume more power than a non o-ring chain. It is much easier to change ratios with a chain drive. Chain drives require some slack, and the losses will be high if they are too tight. There is not really any power lost because of the chain slack, at least until it starts jumping teeth. There is not necessarily any HP consumed by rotating things - a wheel in the absence of friction (space for example) would rotate forever with no power input. Angular momentum is conserved exactly like linear momentum. The weight of the wheel, sprocket and chain, only effects the acceleration, not steady state power requirements, except through higher rolling resistance for a higher weight bike. That equation on the page you referenced is just the ratio of HP to torque, and has nothing to do with drive train losses. It also takes a fair bit of work to get from there to torque or HP required to accelerate the drive train. Kevin Caldwell Courtenay, BC Lauren & Nathan wrote: the next thing to look at could be whether running a belt drive could also aid in power transmission. no slack=no power sag when you twist your throttle measure the weight of your rear wheel, sprockets, disks, chains etc, and you could use an equation to find out how much horse power is used to turn all this at certain tourque/rpm measures http://www.ajdesigner.com/phphorsepower/horsepower_equation_rotating_horsepower.php they could help you out Message: 3 Date: Sun, 11 Mar 2007 14:29:28 EDT From: [EMAIL PROTECTED] Subject: [ElectricMotorcycles] Motor Load and DriveLine Losses - Observations and Questions To: ListServ@electricmotorcycles.net Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; charset="us-ascii" There is thread on the EVDL about what are the normal drive-line losses in a Front Wheel Drive car. It got me thinking, so I put the Ninja un the center stand and did some tests for you to comment on. Test 1 - Bike on center stand, measured motor amps, falls quickly to ~29.5 amps at about 1500 rpms. Is this normal? Test 2 - Bike on center stand, removed read disk brake, no change in motor amps consumed. So far so good. Test 3 - Bike on center stand, removed all drive line loads (e.g. no chain or rear wheel or bearing losses) 19.5 amps. This seems to be a lot just to turn over the ADC 6.7" motor? Things noted during the tests - I can turn the motor with my hand on the shaft with moderate effort. It doesn't turn as easy I thought. - the motor makes a small squeaking noise when (un powered by hand) turning slowly. Is this sound the brushes rubbing or do I need to suspect bearings? I don't suspect any issues, just curious. - I found that the chain was too tight and the alignment is not perfect. I have some motor mount bolts that need to be addressed to get the alignment perfect. Any thoughts of suggestions appreciated. Any other tests that I should try? Mike Bachand Denver Electric Vehicle Council (DEVC) - Colorado Chapter of the EAA 1994 Kawasaki Ninja EV Message: 4 Date: Sun, 11 Mar 2007 17:03:07 -0400 From: "BadFishRacing" <[EMAIL PROTECTED]> Subject: Re: [ElectricMotorcycles] Motor Load and DriveLine Losses -Observations and Questions To: "ElectricMotorcycles" Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; charset="iso-8859-1" I've tried similar things with my twin etek setup. Started with just the motors spinning. Then added the transmission. Then added the rear wheel. No one thing was a big amp drag, but they all add up. So I think all is well. But one thing I also notice is that with the brushes removed (easy to do on the etek), the motor turns over a lot easier by hand. I'd say there's more drag due to the brushes than the bearings, etc. Don't know if you could do the same, pop the springs off of the brushes. And Yes, I've got squeaking from the brushes too. Plus realize that you're powering the series field, even with no load on the motor. Darin BadFishRacing -- Message: 6 Date: Mon, 12 Mar 2007 10:08:40 EDT From: [EMAIL PROTECTED] Subject: Re: [ElectricMotorcycles] Motor Load and DriveLine Losses -Observations and Q... To: listserv@electricmotorcycles.net Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; charset="us-ascii" Thanks For the input Darin. I guess in all the data I forgot some conclusions. 1) Unlike the car folks, dragging disks (assuming a properly aligned rear wheel) don't seem to be much of an issue on an electric motorcycle. 2) Despite my search for a range killer in my direct drive line the chain, wheel bearings etc. account for only 10 amps or so and that seems acceptable. - Mike B. Mike Bachand Denver Electric Vehicle Council (DEVC) - Colorado Chapter of the EAA 1994 Kawasaki Ninja EV **
Re: [ElectricMotorcycles] " Motor Load and DriveLine Losses - Observations and Questions" ListServ Digest, Vol 18, Issue 12
the next thing to look at could be whether running a belt drive could also aid in power transmission. no slack=no power sag when you twist your throttle measure the weight of your rear wheel, sprockets, disks, chains etc, and you could use an equation to find out how much horse power is used to turn all this at certain tourque/rpm measures http://www.ajdesigner.com/phphorsepower/horsepower_equation_rotating_horsepower.php they could help you out Message: 3 Date: Sun, 11 Mar 2007 14:29:28 EDT From: [EMAIL PROTECTED] Subject: [ElectricMotorcycles] Motor Load and DriveLine Losses - Observations and Questions To: ListServ@electricmotorcycles.net Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; charset="us-ascii" There is thread on the EVDL about what are the normal drive-line losses in a Front Wheel Drive car. It got me thinking, so I put the Ninja un the center stand and did some tests for you to comment on. Test 1 - Bike on center stand, measured motor amps, falls quickly to ~29.5 amps at about 1500 rpms. Is this normal? Test 2 - Bike on center stand, removed read disk brake, no change in motor amps consumed. So far so good. Test 3 - Bike on center stand, removed all drive line loads (e.g. no chain or rear wheel or bearing losses) 19.5 amps. This seems to be a lot just to turn over the ADC 6.7" motor? Things noted during the tests - I can turn the motor with my hand on the shaft with moderate effort. It doesn't turn as easy I thought. - the motor makes a small squeaking noise when (un powered by hand) turning slowly. Is this sound the brushes rubbing or do I need to suspect bearings? I don't suspect any issues, just curious. - I found that the chain was too tight and the alignment is not perfect. I have some motor mount bolts that need to be addressed to get the alignment perfect. Any thoughts of suggestions appreciated. Any other tests that I should try? Mike Bachand Denver Electric Vehicle Council (DEVC) - Colorado Chapter of the EAA 1994 Kawasaki Ninja EV Message: 4 Date: Sun, 11 Mar 2007 17:03:07 -0400 From: "BadFishRacing" <[EMAIL PROTECTED]> Subject: Re: [ElectricMotorcycles] Motor Load and DriveLine Losses -Observations and Questions To: "ElectricMotorcycles" Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; charset="iso-8859-1" I've tried similar things with my twin etek setup. Started with just the motors spinning. Then added the transmission. Then added the rear wheel. No one thing was a big amp drag, but they all add up. So I think all is well. But one thing I also notice is that with the brushes removed (easy to do on the etek), the motor turns over a lot easier by hand. I'd say there's more drag due to the brushes than the bearings, etc. Don't know if you could do the same, pop the springs off of the brushes. And Yes, I've got squeaking from the brushes too. Plus realize that you're powering the series field, even with no load on the motor. Darin BadFishRacing -- Message: 6 Date: Mon, 12 Mar 2007 10:08:40 EDT From: [EMAIL PROTECTED] Subject: Re: [ElectricMotorcycles] Motor Load and DriveLine Losses -Observations and Q... To: listserv@electricmotorcycles.net Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; charset="us-ascii" Thanks For the input Darin. I guess in all the data I forgot some conclusions. 1) Unlike the car folks, dragging disks (assuming a properly aligned rear wheel) don't seem to be much of an issue on an electric motorcycle. 2) Despite my search for a range killer in my direct drive line the chain, wheel bearings etc. account for only 10 amps or so and that seems acceptable. - Mike B. Mike Bachand Denver Electric Vehicle Council (DEVC) - Colorado Chapter of the EAA 1994 Kawasaki Ninja EV ** AOL now offers free email to everyone. Find out more about what's free from AOL at http://www.aol.com. -- next part -- An HTML attachment was scrubbed... URL: http://electricmotorcycles.net/pipermail/listserv_electricmotorcycles.net/attachments/20070312/728c49f1/attachment-0001.html End of ListServ Digest, Vol 18, Issue 12
