Control apparatus for elevator
First Claim
1. A control apparatus for an elevator comprising a converter which converts electric power of an A.C. power source in a normal state into direct current while the A.C. power source is normal and which has a battery connected thereto and operates as a step- up chopper when the A.C. power source stops, a capacitor which smooths the output of said converter during the normal state of the A.C. power source and which is charged to a voltage double that of the battery during the stoppage of the A.C. power source, an inverter which receives the voltage of said capacitor to invert it into alternating current of variable voltage and variable frequency and which supplies the alternating current to an electric motor for driving the cage of the elevator, and a control device which controls said converter in pulse width modulation during the normal state of the A.C. power source and controls it as the chopper during the stoppage of the A.C. power source.
1 Assignment
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Accused Products
Abstract
An elevator wherein an electric motor for driving the cage of the elevator is driven by the use of alternating current produced by an inverter, comprising a converter which feeds D.C. power to the inverter and which is so arranged that a plurality of transistors are connected into a bridge corresponding to the number of phases of an A.C. power source connected on the input side of the converter and that diodes are connected to the respective transistors in inverse parallel relationship. In addition, a battery to be used in emergency is connected on the input side of the converter. The converter is controlled in the pulse width modulation in the normal state of the A.C. power source, and the converter connected to the battery is controlled as a chopper during the stoppage of the power source, thereby making it possible to run the elevator at high speed even with the battery of low voltage.
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Citations
6 Claims
- 1. A control apparatus for an elevator comprising a converter which converts electric power of an A.C. power source in a normal state into direct current while the A.C. power source is normal and which has a battery connected thereto and operates as a step- up chopper when the A.C. power source stops, a capacitor which smooths the output of said converter during the normal state of the A.C. power source and which is charged to a voltage double that of the battery during the stoppage of the A.C. power source, an inverter which receives the voltage of said capacitor to invert it into alternating current of variable voltage and variable frequency and which supplies the alternating current to an electric motor for driving the cage of the elevator, and a control device which controls said converter in pulse width modulation during the normal state of the A.C. power source and controls it as the chopper during the stoppage of the A.C. power source.
Specification