I connected a small motor hub to the gearhead of the motor. Then, I measured the voltage, current and speed of turning using a tachometer. I am not sure if the added weight/inertia due to the 12g hub could be neglected in the calculations. Here is the data:
Supplied voltage: 11.1V
Measured voltage across the motor: 10.2V
Measured current in series with the motor: 1.2A
Speed (with the gearhead and hub): 78RPM (8.17 rad/s).
I also removed the gearhead and measured the voltage across the motor and current in series with the motor while the motor was stalled. I did 10 runs using an applied voltage of 5Volt (higher voltage caused smoke). Using R = average of measured V divided by average of measured I, I obtained a resistance of 0.1 Ohms. Is this the resistance of the coil inside the motor?
Based on these data, can I calculated the Back EMF constant, Torque constant and Voltage caused by the Back EMF? I believe the Back EMF constant is the same as the torque constant.
Any advice appreciated. Thanks.