| 摘要 |
<p>1,112,377. Control of motors. ENGLISH ELECTRIC CO. Ltd. 4 Aug., 1965 [5 Aug., 1964], No. 31873/64. Heading H2J. [Also in Division G3] When a drive motor moves a cage from a datum position in a mine shaft, counter 12 receives pulses from generator 10, the number counted from zero being proportional to the distance the cage has travelled. The output signal of the counter is converted to an analogue signal so that square-root function generator 19 produces a speed reference signal. At a predetermined distance from the datum, the counter provides a signal for gate 15 which produces an inhibit signal to gate 11 whereby the counter is rendered insensitive to further pulses from the generator 10. Thereafter the speed reference signal has a constant magnitude. When the cage passes a fixed point in the shaft, a retardation signal from memory device 13 prevents gate 15 from producing the inhibit signal and energizes controller 14 to subtract the pulses derived from generator 10 from the number registered in the counter which commences to count down towards zero. The speed reference signal is thus reduced according to a decelerating part of a preset speed-distance cycle. When the cage is within a creep-speed zone, gate 22 energizes amplifier 24 so that the reference signal is now derived from generator 26. Manual control of the speed of the drive motor is effected by controller 30 associated with reference counter 28. Manual operation lies within the limits set by the speed-distance cycle. When the number of pulse counts representing the speed set by controller 30 is equal to the number registered in counter 28, comparator 29 produces a control signal for gate 27 which renders the counter 28 insensitive to further pulses from generator 10. Counter 18 is then supplied with a steady signal. If the controller 30 is adjusted for lower speed, comparator 29 actuates controller 32 whereby counter 28 subtracts pulses and cancels the signal to gate 27. The reference counter then counts down until the number of pulses set by the manual controller equals the number registered in the counter. Comparator 31 prevents the number registered in counter 28 from exceeding the number in counter 12. The square-root function generator provides linear acceleration and deceleration.</p> |
