| 摘要 |
<p>1299189 Measuring speed electrically BROWN BOVERI & CO Ltd 24 Dec 1969 62916/69 Addition to 1219836 Heading G1N [Also in Division H2] The motor control system of the Parent Specification is modified in that the A. C. tachogenerator now comprises a wound rotor induction machine 2 of which one winding is energized from a three phase supply U N , and in which the winding axis of the stator or rotor may be shifted relative to that of the controlled motor. The shifting is effected by manual or servo driven rack and pinion on the stator, or by a lever operated adjustable coupling, 9, 10, Fig. 1 (not shown). The output of the tachogenerator has a component relating to the frequency of the supply U N in addition to the desired speed of rotation and this unwanted component is removed by the circuit shown in which this component is isolated and reversed 180 degrees in phase for substration at 16. The resulting output has a frequency corresponding to the speed of the motor only, down to zero speed, and its amplitude is kept constant by a feedback circuit in which it (plus a quadrature voltage V90) is rectified at 18, compared with a reference at 19 and the error amplified at 20 for application at 12. The quadrature outputs are applied to the potentiometers of the complete system described in the Parent Specification.</p> |
