I'm in the process of building a spinner, and I'm currently at the point of selecting a motor to power the blade. I have been reading this thread , and I am somewhat confused by the recommendation people have given for the motor.
Now I should add, I am completely new to electronics really - I come from a physics background (I know how electromagnetism works on a basic level, but circuitry and actually building electronic systems is beyond my scope). When I have been looking at the ratings for these brushless motors, KV seems to be the cover-all parameter for the power of the motor. However, as I understand it, this parameter measures the maximum angular velocity of the motor for a given voltage (And therefore, indirectly, the torque the motor produces), and the part recommended is not the part with the highest KV to weight ratio on the HobbyKing store - which looks suboptimal to my untrained eye.
One possible explanation for this is that the KV rating does not directly measure torque, but is a measure of some internal limitation that brushless motors have that is currently beyond my sphere of knowledge. Some of the motors on the site also seem to have power outputs, measured in Watts, but not all. This leads me to believe that it is the power of the motor assuming that you are running it at the maximum voltage - Wich I probably won't be, as I'll be running at 7.4V, so doesn't seem relevant.
Can anyone shed any light on this? I've been trawling the internet for reading material about these things but it's proving frustratingly opaque.
Here are some of the motors I have been looking at, I would appreciate it if someone more expert than I would cast their eye over them and give me their thoughts!
- Hummingbirds CH05XL 8000kv Brushless Motor - This seems to me like it's ridiculously powerful compared to everything else - I must be missing something.
- HobbyKing AP03 4000kv Brushless Micro Motor (3.1g) - This seems very good for its mass. Bear in mind, it seems to run at twice the speed of the part recommended and has only a fraction of the mass.
- MultiStar Viking 1308-4100KV Brushless Outrunner Drone Racing Motor - This motor lists 'Max current: 200w' - I assume it means 'Power', right? If so, that seems very high.
Thanks for your time, guys!