KV and current capacity are the two most important charistics needed
when selecting a motor for your model. This is particularly true in the
case of brushless outrunners which have become so common today.
The tool below can be used to find the actual KV of a brushless motor.
1) Drive the motor at a constant speed with a drill press or hand drill.
and measure the AC voltage between any two of the 3 leads.
Enter this value in the box labeled "motor output voltage".
2) The motor RPM may be taken off the nameplate on the drill or you can mount
a small propeller on a bolt, chuck it in the drill and measure the RPM with an
optical tachometer. Enter the value obtained in the box labeled "motor RPM".
Click SUBMIT and the values of KV and KT will be displayed to the right.
Collected Motor Parameters
KV & KT
The Motor's KV:
The Motor's KT:
The current capacity of a motor can be hard to acertain but it is closely
related to the motor's weight. As I expand the calculations on this page,
the motor weight will be used to help in selecting an appropriate power
system for your aircraft model.