US3683264A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Adaptive limit current
Assignee: Reliance Electric Co
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Filing: 1970-11-12
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Granted: 1972-08-08
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Expires: 1990-11-12
Abstract
Abstract A limit circuit responsive to varying input line voltages to an inverter in order to establish a variable current limit value or maximum current at which the inverter circuit is allowed to operate. If the load current attempts to exceed a variable value established by the input line voltage, the current is limited, and in the preferred embodiment the current is electronically interrupted.
Inventors
- 👤 Robert G Schieman
- 👤 Lee J Penkowski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:56
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/10; H02H7/12; H02H7/122; H02H3/00; H02H3/20
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
186 words
An adaptive limit circuit for an inverter changing DC into AC operable from a fluctuating power source having power input terminals and supplying current to load terminals, comprising in combination, first sensing means establishing a first signal proportional to the magnitude of the voltage across the power input terminals, second sensing means establishing a second signal proportional to the magnitude of the current to the load terminals, capacitor means connected to the inverter to commutate the current to the load terminals, said capacitor means having an increased commutation ability with increased voltage at the power input terminals, and control means including a comparator comparing said first and second signals to limit the current to the load terminals in response to the magnitude of said second signal exceeding the magnitude of said first signal to increase the limit value of the current to the load terminals in direct proportion to an increase of the voltage at the power input terminals and to decrease the limit value of the current to the load terminals in direct proportion to a decrease of the voltage at the power input terminals.
Claim 2
Dependent Claim
186 words
An adaptive limit circuit for an inverter changing DC into AC operable from a fluctuating power source having power input terminals and supplying current to load terminals, comprising in combination, first sensing means establishing a first signal proportional to the magnitude of the voltage across the power input terminals, second sensing means establishing a second signal proportional to the magnitude of the current to the load terminals, capacitor means connected to the inverter to commutate the current to the load terminals, said capacitor means having an increased commutation ability with increased voltage at the power input terminals, and control means including a comparator comparing said first and second signals to limit the current to the load terminals in response to the magnitude of said second signal exceeding the magnitude of said first signal to increase the limit value of the current to the load terminals in direct proportion to an increase of the voltage at the power input terminals and to decrease the limit value of the current to the load terminals in direct proportion to a decrease of the voltage at the power input terminals.
Claim 3
Dependent Claim
42 words
An adaptive limit circuit as set forth in claim 1, including semiconductor switch means connected between the power and load terminals to carry current to the load terminals, and said capacitor means connected to said switch means to commutate the current therebetween.
Claim 4
Dependent Claim
36 words
A limit circuit as set forth in claim 1, wherein said first and second signals are first and second voltages proportional to the magnitude of the input voltage and the magnitude of the output current respectively.
Claim 5
Dependent Claim
24 words
A limit circuit as set forth in claim 1, including means responsive to the comparator output to interrupt the current output of the inverter.
Claim 6
Dependent Claim
23 words
A limit circuit as set forth in claim 1, wherein said control means includes means to algebraically sum said first and second signals.
Claim 7
Dependent Claim
68 words
A limit circuit as set forth in claim 1, including, plural semi-conductor devices acting as switch means, a first group of said semi-conductor devices connected to a positive input terminal, a second group of said semi-conductor devices connected to a negative input terminal, and said control means operative to establish conduction of all semiconductor devices in one of said groups upon said second signal exceeding said first signal.
Claim 8
Dependent Claim
25 words
A limit circuit as set forth in claim 1, wherein said control means limits the current output upon said first signal exceeding a limit value.
Claim 9
Dependent Claim
40 words
A limit circuit as set forth in claim 1, including a voltage limit circuit in said control means, and said voltage limit circuit connected to limit the current output of the inverter upon the input voltage exceeding a limit value.
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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) | 1975-08-08 | 1976-02-07 | 1976-08-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-08 | 1980-02-07 | 1980-08-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-08 | 1984-02-07 | 1984-08-08 | $7700.00 | Window Closed / Lapsed |