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Elevator control apparatus
| Details |
Inventors: Ohira, Takeshi; Kameyama, Tadao; Honzyo, Chihiko; Iwasa, Yuzaburo; Hatakeyama, Takanobu;
Assignee: Hitachi, Ltd. (JP)
Primary Examiner: Rubinson; Gene Z.
Assistant Examiner: Duncanson, Jr.; W. E.
Attorney, Agent or Firm: Craig & Antonelli
An elevator car control apparatus is disclosed in which a three-phase AC tachometer generator is coupled to a motor for driving an elevator car, and the AC output of the tachometer generator is full-wave rectified for use as a speed feedback voltage. A waveform-shaping circuit generates one pulse for each cycle of the output of the AC tachometer generator. A counter counts such pulses after the car has passed a deceleration-initiating point, thereby producing the number of counts proportional to a car running distance after the passage of the deceleration-initiating point. From this number of counts, a deceleration command voltage decreasing progressively in accordance with car positions is obtained by a decoder and a digital-analog converter. During deceleration, the car-drive motor is subjected to feedback control in accordance with the difference between the speed feedback voltage and the deceleration command voltage, thus effecting deceleration control of the elevator car. |
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DETAILED DESCRIPTION What we claim is: 1.
An elevator control apparatus including a motor for driving a car running in an elevator hoistway, a device for generating a speed command signal in accordance with the position of said car, and a device for controlling said motor in response to said speed command signal and a feedback signal of the speed of said motor; said elevator control apparatus further comprising an AC tachometer generator driven by said car drive motor, a rectifier circuit for rectifying the output of said AC tachometer generator to deliver said speed feedback signal, and a counter for detecting a car position by counting the number proportional to the output frequency of said AC tachometer generator.
2.
An elevator control apparatus according to claim 1, further comprising a waveform-shaping circuit for shaping the waveform of the output of said AC tachometer generator and producing pulses whose number is proportional to the output frequency of said AC tachometer generator, said counter counting the output pulses produced from said wave-form-shaping circuit.
3.
An elevator control apparatus according to claim 2, in which said waveform-shaping circuit generates one pulse for each cycle of the output of said AC tachometer generator.
4.
An elevator control apparatus according to claim 1, in which said rectifier circuit comprises a full-wave rectifier bridge circuit including a plurality of diodes, and said counter counts a signal proportional to the output frequency of said AC tachometer generator taken out of one arm of said full-wave rectifier bridge circuit.
5.
An elevator control apparatus according to claim 1, in which said AC tachometer generator is a three-phase AC tachometer generator and said rectifier is a three-phase full-wave rectifier bridge circuit for full-wave rectifying the output of said three-phase AC tachometer generator, and in which said apparatus further comprises a circuit for shaping a signal proportional to the output frequency of said three-phase AC tachometer generator taken out of one arm of said three-phase full-wave rectifier bridge circuit, into a pulse which is counted by said counter
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