US4721188A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control apparatus for A.C. elevator
Assignee: Mitsubishi Electric Corp
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Filing: 1987-04-01
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Granted: 1988-01-26
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Expires: 2007-04-01
Abstract
Abstract A control apparatus for an A.C. elevator comprises resistances connected between an A.C. power source and a converter, a detection device to detect the build-up rate of the charged voltage of a smoothing capacitor, and control means to generate a signal for closing a contact interposed between the A.C. power source and the converter, when the output of the detection device is not greater than a predetermined value. The detection and control devices are preferably provided by a microcomputer.
Inventors
- 👤 Hiroshi Araki
- 👤 Tooru Tanahashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:46
CPC Classifications
B; B66; B66B; B66B1/00; B66B1/24; B66B1/28; B66B1/30; B66B1/308
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
142 words
A control apparatus for an A.C. elevator, comprising: a converter which is connected to an A.C. power source through a first contact, and by which A.C. power fed from the A.C. power source is converted into direct current, a smoothing capacitor which smooths the D.C. output of said converter, an inverter by which a smoothed output from said smoothing capacitor is inverted into A.C. power of variable frequency, an induction motor which is driven by the A.C. output of said inverter and which operates a cage of the elevator, impedance elements which are connected between the A.C. power source and said converter, detection means to detect a build-up rate of a charged voltage of said smoothing capacitor, and control means to generate a signal for closing said first contact when the output of said detection means does not exceed a predetermined value.
Claim 2
Dependent Claim
142 words
A control apparatus for an A.C. elevator, comprising: a converter which is connected to an A.C. power source through a first contact, and by which A.C. power fed from the A.C. power source is converted into direct current, a smoothing capacitor which smooths the D.C. output of said converter, an inverter by which a smoothed output from said smoothing capacitor is inverted into A.C. power of variable frequency, an induction motor which is driven by the A.C. output of said inverter and which operates a cage of the elevator, impedance elements which are connected between the A.C. power source and said converter, detection means to detect a build-up rate of a charged voltage of said smoothing capacitor, and control means to generate a signal for closing said first contact when the output of said detection means does not exceed a predetermined value.
Claim 3
Dependent Claim
20 words
A control apparatus for an A.C. elevator as defined in claim 1, wherein said each impedance element is a resistor.
Claim 4
Dependent Claim
24 words
A control apparatus for an A.C. elevator as defined in claim 1, wherein A.C. reactors are connected between said first contact and said converter.
Claim 5
Dependent Claim
38 words
A control apparatus for an A.C. elevator as defined in claim 1, wherein a second contact is connected between the A.C. power source and said impedance elements, and it is closed by a start command for the cage.
Claim 6
Dependent Claim
25 words
A control apparatus for an A.C. elevator as defined in claim 1, wherein said detection means and said control means are constructed by a microcomputer.
Claim 7
Dependent Claim
53 words
A control apparatus for an A.C. elevator as defined in claim 5, wherein said microcomputer is fed with a signal obtained by amplifying the charged voltage of said smoothing capacitor and then subjecting the amplified voltage to analog-to-digital conversion, and it delivers the signal for controlling opening and closure of said first contact.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-01-25 | 1991-07-27 | 1992-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-01-25 | 1995-07-27 | 1996-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-01-25 | 1999-07-27 | 2000-01-26 | $7700.00 | Window Closed / Lapsed |