Recent content by magnethead494

One would think so, but it's surprisingly not as big an issue as one would think. The body panels and ground effects are done up to where, once you have the power on tap, air resistance is a very small loss, maybe 4% on MPH. Either way, that's nothing to do with the question I asked. I asked...

Spreadsheet of data: http://i1105.photobucket.com/albums/h355/magnethead494/Screenshot2012-05-14at103445PM.png Example dyno graph: http://i1105.photobucket.com/albums/h355/magnethead494/turbo_busa_dyno_hahn_stg1.jpg I'm familiar with F = MA/G => F*G/M = A for english units (G = 32.17). This...

For safety/overhead tolerances, I say 45 degrees is a good design margin, especially for the size of tire. For MuK of 0.03 (arbitrary for knobby tire on dirt), on flat ground, 0.03 * 9.8 m/s^2 * 68kg = 19.992 kilogram-meter per second squared = 19.992 Newtons of thrust. friction force going...

Thanks. So that would make the numbers indeed make sense, since I came up with a MuK of about .077

Just to be on the safe side, I'll change the 9:25 chain to a 9:32. "Only" a 9 pound-force difference in thrust for a 1.4 foot per second decrease. But as you said, Torque is what I'll need given the conditions. 40.64 pounds of thrust / 6 tires = 6.77 pounds of thrust per tire.

Original design is 4/67 differential gearing and 9" tires. That's it. I posted a picture of the entire motor assy a couple posts up. I'm taking that assy, removing the wheels, and putting 9 tooth sprockets there instead. These then go to 25 tooth sprockets on the center axle. 12 tooth...

Found some new data. The batteries are 22V/55A or 24V/70A depending on options, and the chairs were rated for a 20-25 mile range per charge at up to 4.5 miles per hour. 55A/20Mi = 2.75A/Mi * 4.5Mi/Hr = 12.375 A/Hr @ 22V = 272.25W 55A/25Mi = 2.20A/Mi * 4.5Mi/Hr = 09.900 A/Hr @ 22V = 217.80W...

I'm trying to figure out how it functioned in it's designed life as a handicapped scooter motor. I am thinking the 0.85Nm on the label is an average/standard value, not a stall torque? Because I don't see how (per that calculation) it could have moved an 82Kg/180lb person generating only 62...

If my approximations are correct, 82kG person * g = 804.42 Newtons, with an approx mu/rolling resistance of 0.30, yields 241 Newtons. To do this on a 9 inch tire, would take 55.5 Newton-meters of torque, or 3.3 Newtons from the electric motor. Is that right? or working mu off the .85Nm rating...

Thanks. At this I hypothesize: in "stock" form, with 9 inch wheels, 3000 @ 0.85nM -> 16.75:1 -> 179 @ 14.23 Nm = 179 RPM @ 10.5 pound force feet, 9" tire, equals 7 feet per second at 14 pound-force-feet of thrust. How would this be able to move, say, a 180 pound rider, and not stall?

I'm working with a 3000 RPM @ 0.85 Nm motor in the transaxle from a powered scooter (like for disabled/elderly people). The differential has a 67:4 (16.75) reduction, which puts the output shafts around 179 RPM @ 14.23 Nm. I'm passing this to a 25:9 chain drive, which makes the final output...

didn't try that regulator/convertor/isolator, however, did try a $5 27,000uF capacitor from Mouser, on an O-scope. the green line is without the 27,000 uF cap, the red is with it (slightly less amplitude than shown, unknown wavelength difference)...

no, that issue was related to solid core wires, which nobody uses anymore due to high resistance and EMI. I'm taking the whole ignition setup to the university next week and putting it in an EE lab with a professor's assistance. Going to scope it and try some simple things. I found a 12->12 @...

It did not help. I used the 3900uF.

So the guy with the roadster went from an electric fuel pump to a belt drive fuel pump, and now the LED boards are displaying random segments, like the shift registers are getting some sort or crap signal. But I don't know if it's coming from the controller or from the power line. The shift...