Yeah! Finally! Now i can measure parameters of any motor and debug the controller much easier.
On the right side motor, and on the left side generator. Generator have free-rotating axle, mounted on bearings. You can see a leg of length 102 mm with scales on it. Scales shows torque in Nm of generator. Using simple formula Nm*RPM/9.549 you can find out power and calculate efficiency of motor+controller.
UPD: small video