This paper deals with the servomotor selection to drive the mechanism using an electronic cam. The electronic cam works in a continuous cyclic motion. The mechanism is accelerated and decelerated and the servomotor of the electronic cam has to serve enough of drive torque (drive force) to ensure the required displacement law. The driving torque is not only influenced by external forces and dynamic torque of mechanism, but also the high amount of torque is consumed by accelerating of the servomotor rotor itself. The suitable displacement law influences the motor selection too. The mechanisms in machines are driven by electromotors, such as asynchronous and synchronous motors. The selection of the suitable motor to drive the mechanisms using the electronic cam is important and it depends on the mechanisms and the displacement law. In this case the selection of suitable motor for simply crank mechanism will be shown. The motor is not only loaded by the dynamic forces of mechanism but also by the dynamic force of the rotor of the motor which satisfies the displacement law of the electronic cam.