Brushless DC motor selection

This paper investigates the process of brushless DC motor selection through the specification of load torque and the desired load motion as a function of time. The peak and RMS torque requirements of the application are discussed along with the procedure to find the correct motor size and performance. Gearing and power transmissions are also considered in the drive system so that the required torque speed of the load can be obtained using a higher speed motor. This gives flexibility to the motor selection process but adds some undesired effects such as compliance. A method to select the correct gearing ratio is also included. A design example is given to demonstrate the process