zeroonea wrote: ↑
Jan 04 2018 9:24am
My motor is outrunner brushless 6063 with 6S 40C battery. My ESC is 90A esc. Gear ratio is 12T/55T. I hear someone say it is undergeared or overgeared. What is undergeared and overgeared?
Undergeared or overgeared refers to a poor match between motor speed and desired vehicle speed.
Let's say your motor's constant is 60 RPM/V. That means for a 6S (~22V) battery you will get a "base speed" of 1320 RPM. Now you have to calculate what speed that means; to do that you have to know the gear ratio (.218 in your case) and the wheel diameter. For a 26" wheel that means 22mph.
Now, if you really wanted 10mph you are giving up some torque and not making a good match between your battery and your motor; you would be better off with a lower gear ratio, lower motor constant or a lower voltage. Likewise, if you really wanted 30mph you are going to have to phase-advance like crazy - that's not very efficient, and most controllers don't support it anyway. You'd again be better off with a different gear ratio, motor constant or battery voltage.