Hi David, Thank you for the reply and the welcome! I can't believe I've been missing out on EVDL for this long - it's a great resource! This helps understand the relationship a bit better.
---------------- Hi Alan, Thank you for the response - I appreciate the detail. My next step, as you mentioned, is to find the best setup for acceleration and speed. I most likely will use the motor with a 30% safety-margin from its max of 10000 RPM = 7000 RPM. If I understand correctly, gearing the diff and/or transmission to a higher RPM (within set safety-margin) allows for less required amps along with less heat? Initially, I was under the impression that a lower motor RPM corresponded to a "cooler" motor. Electric Vehicle Discussion List mailing list wrote > Forrest, > > A 28.7" tall tire has a circumference of PI * 28.7 or 3.17*28.7 or 90.98" > or 7.58 feet. > 3,000 motor rpm *1 drive shaft revolution / 3.27 rear axle revolutions = > 917.43 rpm > 917.43 rpm * 7.58 feet circumference of tire = 6,954 feet / minute * 1 > mile > / 5,280 feet = 1.317 miles / minute > * 60 minutes / hour = 79.02 miles per hour. > > At 3,000 rpm, with no transmission, or the transmission in high gear (1:1 > ratio) the 3.27 rear end will spin at 917.43 rpm making a 28.7" tall tire > run 79.02 miles per hour. > > To get the most acceleration and usable speed from the setup, you should > find the maximum safe rpm of the motor, and gear the vehicle just under > that rpm by a safe margin, at a maximum speed that you will not exceed. > Some conversions use second or third gear to get the motor rpm's up. You > could use a shorter tire. One drag racer went to a smaller diameter DC > motor that could spin faster, and then used two motors. > > I hope this helps, > > Alan -- Sent from: http://electric-vehicle-discussion-list.413529.n4.nabble.com/ _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub ARCHIVE: http://www.evdl.org/archive/index.html INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
