US4482031A
Expired / Lapsed
US
⏱️ 0.0 years remaining
AC elevator control apparatus
Assignee: Mitsubishi Electric Corp
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Filing: 1983-03-07
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Granted: 1984-11-13
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Expires: 2003-03-07
Abstract
Abstract Disclosed is an AC elevator control apparatus, in which AC power supplied from an AC source is rectified by a converter and a smoothing capacitor into DC power, the DC power being in turn converted by an inverter into variable-frequency AC power by which an AC electric motor is driven to operate an elevator cage. The apparatus includes a rectifying circuit connected to the AC source, a resistor connected between the rectifying circuit and the smoothing capacitor, a charging time measuring circuit for measuring the time from turn-on of the AC source until the completion of charging the smoothing capacitor, and a control circuit for producing an abnormality detection signal when it is detected that the output of the charging time measuring circuit is shorter than a predetermined value, whereby the reduction in capacitance of the capacitor, and hence the expiration of the lifetime of the same, can be evaluated in advance.
Inventors
- 👤 Masayuki Yoshida
- 👤 Masami Nomura
- 👤 Hiroyuki Ikejima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:19
CPC Classifications
B; B66; B66B; B66B1/00; B66B1/24; B66B1/28; B66B5/00; B66B5/0006; B66B5/0018; B66B5/0031
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
131 words
In an AC elevator control apparatus wherein AC power supplied from an AC source is rectified by a converter and a smoothing capacitor into DC power, the DC power being in turn converted by an inverter into variable-frequency AC power by which an AC electric motor is driven to operate an operator cage, the improvement comprising: a rectifying circuit connected to said AC source; a resistor connected between an output side of said rectifying circuit and said smoothing capacitor; charging time measuring means for measuring the time from turn-on of said AC source until the completion of charging of said smoothing capacitor; and a control circuit for producing an abnormality detection signal when it is detected that an output of said charging time measuring means is shorter than a predetemined value.
Claim 2
Dependent Claim
131 words
In an AC elevator control apparatus wherein AC power supplied from an AC source is rectified by a converter and a smoothing capacitor into DC power, the DC power being in turn converted by an inverter into variable-frequency AC power by which an AC electric motor is driven to operate an operator cage, the improvement comprising: a rectifying circuit connected to said AC source; a resistor connected between an output side of said rectifying circuit and said smoothing capacitor; charging time measuring means for measuring the time from turn-on of said AC source until the completion of charging of said smoothing capacitor; and a control circuit for producing an abnormality detection signal when it is detected that an output of said charging time measuring means is shorter than a predetemined value.
Claim 3
Dependent Claim
55 words
An elevator control apparatus according to claim 1, comprising a contact provided in a circuit from the output side of said rectifying circuit through said resistor to said smoothing capacitor, said contact being arranged so as to be closed for only a predetermined period of time from the initiation of supply of said AC power.
Claim 4
Dependent Claim
22 words
An elevator control apparatus according to claim 2, said inverter and said converter being operationally inhibited during said predetermined period of time.
Claim 5
Dependent Claim
15 words
An elevator control apparatus according to claim 3, said converter including firing-controlled semiconductor switching means.
Claim 6
Dependent Claim
18 words
An elevator control apparatus according to claim 3, said inverter including diode means and firing-controlled semiconductor switching means.
Claim 7
Dependent Claim
38 words
An elevator control apparatus according to claim 4, said control circuit producing a firing command for said switching means of said converter and an operation command for said inverter during times other than said predetermined period of time.
Claim 8
Dependent Claim
106 words
In an AC elevator control apparatus wherein AC power supplied from an AC source is rectified by a converter and a smoothing capacitor into DC power, the DC power being in turn converted by an inverter into variable-frequency AC power by which an AC electric motor is driven to operate as elevator cage, the improvement comprising: a rectifying circuit connected to said AC source; a resistor connected between an output side of said rectifying circuit and said smoothing capacitor; means for detecting a shorter than normal charging time of said smoothing capacitor indicative of the degeneration of said smoothing capacitor, and means for indicating said detection.
Claim 9
Dependent Claim
106 words
In an AC elevator control apparatus wherein AC power supplied from an AC source is rectified by a converter and a smoothing capacitor into DC power, the DC power being in turn converted by an inverter into variable-frequency AC power by which an AC electric motor is driven to operate as elevator cage, the improvement comprising: a rectifying circuit connected to said AC source; a resistor connected between an output side of said rectifying circuit and said smoothing capacitor; means for detecting a shorter than normal charging time of said smoothing capacitor indicative of the degeneration of said smoothing capacitor, and means for indicating said detection.
Claim 10
Dependent Claim
31 words
An elevator control apparatus as claimed in claim 7, said detection means including charging time measuring means and timer means operative for a predetermined time after initiation of said AC power.
Claim 11
Dependent Claim
55 words
An elevator control apparatus as claimed in claim 8, said detection means comprising first and second comparators having first and second reference voltages at one input thereto and a capacitor voltage at the other input thereto, an inverter following said second comparator, and AND gate means receiving the outputs from said comparator and said inverter.
Claim 12
Dependent Claim
54 words
An elevator control apparatus as claimed in claim 9, further including flip-flop means for actuating said indicating means when an output of said AND gate means drops prior to the output of said timer means after the initiation of said AC power, said predetermined time being set shorter than said normal capacitor charging time.
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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) | 1987-11-13 | 1988-05-14 | 1988-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-13 | 1992-05-14 | 1992-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-13 | 1996-05-14 | 1996-11-13 | $7700.00 | Window Closed / Lapsed |