[de_]

fyi: We had a 9015 on before (16K no load), and a 0673 on afterwards (19k no load). The extra rpm was surprising visible (actually way too fast full power) and the power required to sustain the higher rpm was clearly higher (wheel hubs have wind resistance, also the AM planetary has resistance presumidly proportion to the speed they turn). We had a clip on amp meter monitoring amp draw and it would go over 30 amps peak when a ball when through until the rpm recovered. And of course they had to test a ton of balls.. So things got hot.


Update Clarification (sorry): We had the motor driving a AM 3.7/1 planetary driving a chain based gear reduction of 1 to 0.7 (ie wheel turns 0.7 rev per rev of output of AM gearbox). Our wheels are 8". Clearly the motors have to overcome planetary loses, chain loses and wheel turning loses so they are not running at no load speed but they are still pretty fast. We added a second motor also with a fan to spread the heat load between the motors (until we can prove one motor can survive). My best guess we could get away with final chain ratio of 2/1 reduction and one motor.

Last I heard, these motors were only 60% efficent so even at 15 amps, 0.4 x 15 amps x 12v = 72 watts (compare to a 60w light bulb) so things heat up. I've never regretted adding a (little victor) fan to blow in and around one of the brush cooling slots !