Direct Drive to Diff E Revo Build

[sikeston34m]

John, there is alot of valuable motor building information here.

Just trying to pass along some tools that I plan on using.

http://www.bavaria-direct.co.za:80/m...motor_info.htm

[sikeston34m]

One thing that I thought was very interesting is at the bottom of that page. It's how to figure the kv of any motor that's already built.

"Drive your motor with a power drill.
Measure RPM and voltage generated.

Kv = RPM / voltage"

I spun the 4130 at 930rpm with a drill. It was feeding 2.9 volts into a volt meter on the AC scale.

930rpm/2.9volts= 320kv

Pretty close to the factory rating of 305kv! Which maybe with the load of the motor, the drill wasn't quite spinning at 930rpm. I think this is a good quick method though.

[johnrobholmes]

The generator method gives you the kv with consideration to efficiency losses in the motor. Factories do not always do this, and it could explain the small difference you found. Pretty darn close though.