A motor controller "is a device or group of devices that serves to govern in some predetermined manner the performance of an electric motor. A motor controller might include a manual or automatic means for starting and stopping the motor, selecting forward or reverse rotation, selecting and regulating the speed, regulating or limiting the torque, and protecting against overloads and faults."
The Contactor: In electric vehicles a contactor serves to disconnect the battery pack from the rest of the vehicle. A contactor is a switch and turning the contactor on or off connects or disconnects the battery pack. A contactor can be manually operated, or by a relay. Contactors are part of the main power connections in an EV, and it must handle all the power used in the EV.