Electronic tachometer and combined brushless motor commutation and tachometer system

摘要: An electronic tachometer utilizes a transducer, typically an optical encoder disc, connected to movable mechanical element. The transducer produces pair of triangular waves fixed relative phase, each having slopes proportional the velocity are differentiated and resultant signals sampled by gating pulses derived from themselves. samples combined produce output signal magnitude element speed polarity indicative direction. In system in which is attached shaft brushless motor, another same used for commutation control motor stator windings. This arrangement particularly useful servo system, compared with indicating desired velocity. comparator modify so as Position encoding also may be accomplished using transducer.