Abstract: An ESP assembly includes a motor having a stator, a rotor, a drive shaft, and an asymmetric magnetic ring mounted to an end of the drive shaft. Electricity for driving the motor is provided by a power source on surface and delivered to the motor through a power cable inserted into the wellbore. Power cable leads insert into a star connection mounted around an end of the shaft having the ring and that houses a downhole sensor. During operation of the ESP assembly, the sensor tracks the rotor position by monitoring ring rotation. Information about the rotor position is transmitted uphole along the power cable. A controller on surface receives and processes the position information, and delivers control commands to the motor that are transmitted down the power cable. The power cable is connected to the controller and to the sensor by current transformers.