US3859542A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Harmonic and power factor compensation means and method for power systems controlled by a non-linear device
Assignee: Inductotherm Corp
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Filing: 1973-09-12
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Granted: 1975-01-07
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Expires: 1993-09-12
Abstract
Abstract The fundamental frequency power factor is improved and a practical reduction in significant harmonic current is made in electrical power systems where the power to the load is controlled by a non-linear device, such as a saturable reactor, by using series inductive-capacitive filters to filter the significant harmonic current to act as a shunt for harmonic current in conjunction with a supply line inductive reactance. The resonant frequency of each filter is less than the frequency of the harmonic current and the impedance of each said inductivecapacitive filter is a net inductive reactance. The capacitive element of the filter provides a leading power factor component to compensate for the lagging power factor component imposed on the supply system by the non-linear control device.
Inventors
- 👤 Theodore R Kennedy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 12:55
CPC Classifications
H; H03; H03H; H03H7/00; H03H7/01; H03H7/17; H03H7/1741; H03H7/1758; H02; H02J; H02J3/00; H02J3/18; H02J3/1821; H02J3/1828; H03H7/0115; H03H7/1791; Y; Y02; Y02E; Y02E40/00; Y02E40/30; Y02P; Y02P80/00; Y02P80/10
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
93 words
In an electrical power system comprising a load, power factor correcting means, a non-linear device for controlling the power delivered to the load, said non-linear device having an inductive reactance and filter means for filtering harmonic currents, the improvement comprising: said filter means including an inductivecapacitive filter for each of one or more significant harmonic currents, each inductive-capacitive filter being tuned to less than the harmonic frequency of the current which is to filter, and each of said inductive-capacitive filters having a net inductive reactance at the harmonic frequency being filtered by it.
Claim 2
Dependent Claim
93 words
In an electrical power system comprising a load, power factor correcting means, a non-linear device for controlling the power delivered to the load, said non-linear device having an inductive reactance and filter means for filtering harmonic currents, the improvement comprising: said filter means including an inductivecapacitive filter for each of one or more significant harmonic currents, each inductive-capacitive filter being tuned to less than the harmonic frequency of the current which is to filter, and each of said inductive-capacitive filters having a net inductive reactance at the harmonic frequency being filtered by it.
Claim 3
Dependent Claim
19 words
The electrical power system of claim 1 wherein the non-linear device for controlling the power is a saturable reactor.
Claim 4
Dependent Claim
30 words
The electrical power system in accordance with claim 1 wherein said power factor correcting means includes capacitive means for substantially correcting the power factor to unity at the fundamental frequency.
Claim 5
Dependent Claim
129 words
In a process for controlling the power delivered to a load using power factor correcting means, a non-linear device for controlling the power delivered to the load, said non-linear device having an inductive reactance filter means for filtering the harmonic currents, the improvement comprising: providing a series inductive-capacitive filter for each of one or more significant harmonic currents, tuning each inductive-capacitive filter to less than the harmonic frequency which it is to filter, and setting the impedance of each of said inductive-capacitive filters to have a net inductive reactance at the harmonic frequency being passed by it, said net inductive reactance being selected so that the harmonic current attributable to the non-linear control device divides in a predetermined ratio between each harmonic filter and the supply system delivering power.
Claim 6
Dependent Claim
129 words
In a process for controlling the power delivered to a load using power factor correcting means, a non-linear device for controlling the power delivered to the load, said non-linear device having an inductive reactance filter means for filtering the harmonic currents, the improvement comprising: providing a series inductive-capacitive filter for each of one or more significant harmonic currents, tuning each inductive-capacitive filter to less than the harmonic frequency which it is to filter, and setting the impedance of each of said inductive-capacitive filters to have a net inductive reactance at the harmonic frequency being passed by it, said net inductive reactance being selected so that the harmonic current attributable to the non-linear control device divides in a predetermined ratio between each harmonic filter and the supply system delivering power.
Claim 7
Dependent Claim
52 words
The process for controlling the power delivered to a load in accordance with claim 4 including adjusting the capacitive element of each filter to provide a leading power factor component at the supply line frequency to compensate for a lagging power factor component imposed on the supply system by the non-linear device.
Claim 8
Dependent Claim
45 words
The electrical power system of claim 1 wherein the micro-farad value of the capacitive elements of the filters provide a leading power factor component at the supply frequency to compensate for the lagging power factor component imposed on the supply system by the non-linear device.
Claim 9
Dependent Claim
149 words
In an electrical power system for an inductive load, said iNductive load being an induction furnace, power factor correcting means for said inductive load, a non-linear device comprising a saturable reactor for delivering power to the load, said non-linear device having an inductive reactance, and filter means for filtering harmonic currents, the improvement comprising: said filter means including an inductive-capacitive filter for each of one or more significant harmonic currents, each inductive-capacitive filter being tuned to less than the harmonic frequency of the current which it is to filter, each of said inductive-capacitive filters having a net inductive reactance at the harmonic frequency being filtered by it, and the micro-farad value of the capacitive elements of the filters being such as to provide a leading power factor component at the supply frequency to compensate for the lagging power factor component imposed on the supply system by the non-linear device.
Claim 10
Dependent Claim
149 words
In an electrical power system for an inductive load, said iNductive load being an induction furnace, power factor correcting means for said inductive load, a non-linear device comprising a saturable reactor for delivering power to the load, said non-linear device having an inductive reactance, and filter means for filtering harmonic currents, the improvement comprising: said filter means including an inductive-capacitive filter for each of one or more significant harmonic currents, each inductive-capacitive filter being tuned to less than the harmonic frequency of the current which it is to filter, each of said inductive-capacitive filters having a net inductive reactance at the harmonic frequency being filtered by it, and the micro-farad value of the capacitive elements of the filters being such as to provide a leading power factor component at the supply frequency to compensate for the lagging power factor component imposed on the supply system by the non-linear device.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-01-06 | 1978-07-08 | 1979-01-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-06 | 1982-07-08 | 1983-01-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-06 | 1986-07-08 | 1987-01-07 | $7700.00 | Window Closed / Lapsed |