Elevator power source device

• US 5,058,710 A
• Filed: 08/14/1990
• Issued: 10/22/1991
• Est. Priority Date: 08/14/1990
• Status: Expired due to Fees

• Current Assignee: Otis Elevator Company (Otis Worldwide Corp.)
• Original Assignee: Otis Elevator Company (Otis Worldwide Corp.)
• Inventors: Iwasa, Masao
• Primary Examiner(s): Deboer, Todd E.
• Assistant Examiner(s): Duncanson, Jr., W. E.
• Application Number:
  US07/567,422
• Time in Patent Office: 434 Days
• Field of Search: 187/114, 187/119, 318/807-811, 363/34, 363/37
• US Class Current: 187/290
• CPC Class Codes: B66B 5/02 responsive to abnormal operating conditions
• CPC Class Codes: Y02B 50/00 Energy efficient technologies in elevators, escalators and moving walkways, e.g. energy saving or recuperation technologies

Abstract

A simplified elevator power system using an AC-DC converter, both to convert AC to DC during normal operation and to convert stored DC power to AC during power failures. A power source monitoring relay monitors AC power coming from a utility, and upon power failure, switches a battery from a charging mode to a power source mode wherein DC power is supplied, not only to an inverter for driving a motor, but also to a converter hooked up to run as an inverter during such power failure in order to provide stepped-up AC voltage to elevator control devices. In this way, the prior art addition of an extra inverter is avoided.

Claims

1. An elevator power source device comprising:

a power source monitoring relay connected to power lines supplying AC power from a commercial power source;

an AC-DC converter which has its input side connected to said power lines;

a DC-AC inverter which has its input side connected to an output side of said AC-DC converter and is used to control a motor;

a battery connected to said output side of said AC-DC converter via contacts (in the case of power failure) of said power source monitoring relay;

a battery charger which is connected to said power lines via contacts (in the case of power failure) of said power source monitoring relay;

a step-up transformer which is connected to the input side of said AC-DC converter via contacts (in the case of power failure) of said power source monitoring relay, and which generates an elevator control voltage; and

a converter switch circuit which is connected to said power source monitoring relay and said AC-DC converter, which controls the transistors of said AC-DC converter without power failure so that said AC-DC converter operates as an AC-DC converter, and which controls the transistors of said AC-DC converter during power failure so that said AC-DC converter operates as a DC-AC inverter.

2. Apparatus for use during a primary power failure in a motor drive having an AC to DC converter, a DC link, a DC to AC inverter, means for sensing AC provided to an AC port of said AC to DC converter for providing an AC failure signal in the presence of a primary power failure and means for providing stored DC to said DC link in response to said failure signal, comprising:

means, responsive to said failure signal, for providing a first control signal to said AC to DC converter in the absence of said failure signal; and

means for providing a second control signal to said AC to DC converter, in response to said failure signal, for providing AC at said first port.

3. A method for use during a primary power failure in a motor drive having an AC to DC converter, a DC link and a DC to AC inverter, comprising the steps of:

sensing AC provided to a first port of said AC to DC converter for providing an AC failure signal in the presence thereof;

providing stored DC to a second port of said AC to DC converter connected to said DC link, in response to said failure signal; and

providing a control signal to said AC to DC converter, in response to said failure signal, for providing AC at said first port.