ARRANGEMENT FOR CONTROLLING A UNIT THAT CAN BE AIMED, PREFERABLY A WEAPON SIGHT, BY MEANS OF A THREE-PHASE BRUSHLESS DIRECT-CURRENT MOTOR

摘要

In an arrangement a three-phase brushless direct-current motor (MOT) is utilized for controlling a weapon sight (VP), using electrical signals. The arrangement comprises an analogue or digital motor amplifier for sinusoidal commutation, to which the electrical signals can be fed. The windings or phases of the motor are connected to individual pairs of drive transistors incorporated in a transistor bridge. The motor amplifier is arranged to generate pulse-width-modulated signals (PWM-R, PWM-S and PWM-T) and using these to control the drive transistors in the bridge and thereby cause generation of the phase drive currents in the motor's windings. Galvanically-isolated circuits (HE, HS and HE', HS' respectively) effect current feedback from the motor to the inpuT of the amplifier.