Motor size VS RPM VS power
Hi all, I have a real quick question; should I use a cheaper, smaller, LIGHTER, higher rpm motor from the RC hobby world or a larger, heavier, more expensive motor? Here are the details:
For some type of small electric vehicle, think between the size and weight of an electric skateboard, and the size and weight of a go-kart. I have been wanting to build a small 4 wheeled kart that leans with steering input, so something along those lines.
The options are:
A semi-industrial 48V 1000W motor that can be found all over ebay. These are typically 4"-5" in diameter and 7"-8" long; quite a bit of heft compared to the smaller motors; and 3000 RPM.
A large RC plane motor with continuous 60 amp rating at 48V, so nearly 3000 watts. But it is also nearly a 10,000 RPM motor at 48V.
I have designed equipment for a few years that often gets 3HP-10HP drives for chain runs and I have also been into RC planes for a long time. I get that wiring a motor "hotter" with larger wire and fewer turns brings you more amps/power and higher RPM. And I understand the HP to torque relationship, HP = Torque x RPM ÷ 5252.
So, a more refined version of my question would be, since a motors power is constant, but torque can be manipulated, why would anyone use the heavier motors with less power? True they have more torque at lower RPMs (if their power ratings are the same).