Abstract: A brushless servo motor for connection to a rotatable load without the need for initial adjustment and calibration of the external position servo loop. A plurality of keyways, keys, pins and projections ensure alignment of motor and position sensor rotors, motor and position sensor stators, motor and load shafts, and motor and load housings to eliminate the need for extensive adjustments. This also facilitates motor replacement without the need for readjustments.

Abstract: A current and torque feedback system for use with sine-wave controlled brushless servo motors each having a plurality of stator windings, a permanent magnet rotor and a rotor position sensor. Current sensors detect instantaneous values of electrical currents in each of the stator windings; and circuitry computes peak current values and electrical polarity of each current. Circuitry uses sensor signals from the rotor position sensor to divide the electrical revolution of the brushless motor into a number of regions equal to the number of phases of the brushless motor with each of the regions centered about the peak values of the sensed currents. The peak values of the currents and the current polarities are coupled to circuitry which generates an output signal having a value proportional to the peak values of the currents and having a polarity indicative of the direction of the torque generated by the brushless motor.