Patent US5077486A successfully refreshed from Google Patents.
US5077486A
Expired / Lapsed
US
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Power supply for cathodic protection system
Assignee: RTS ELECTRONIC MANUFACTURING Ltd A CORP OF CANADA
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Filing: 1988-03-21
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Granted: 1991-12-31
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Expires: 2008-03-21
Abstract
Abstract A power module for a cathodic protection system is provided having a switch-mode power circuit and a synchronous switch assembly. The method of the invention comprises rectifying an alternating utility power signal with a power transformer and switch assembly. The switch assembly is controlled by a phase control circuit to provide a selective controlled phase delay to provide a 0-100% range power signal to the load selectively operable in a constant current, constant voltage or off-potential manner.
Inventors
- 👤 Gary Marson
- 👤 Art W. Gaber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 16:28
CPC Classifications
C; C23; C23F; C23F13/00; C23F13/02; C23F13/04; G; G01; G01N; G01N17/00; G01N17/02; H; H02; H02M; H02M3/00; H02M3/22; H02M3/24; H02M3/28; H02M3/325; H02M3/335; H02M3/33569; H02M3/33576; H02M3/33592; Y; Y02; Y02B; Y02B70/00; Y02B70/10
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
172 words
An assembly for cathodically protecting a structure by impressing a selective electrical potential upon the structure with high frequency switching, said impressing being selectively operable in either a constant current, a constant voltage, or an auto-potential mode, said assembly comprising: a source of an alternating voltage power signal; a switch mode power circuit means for generating a square wave voltage form the source; a power transformer having a primary side winding and a secondary side winding, the primary side winding being driven by the power circuit means, the secondary side winding having a tap to divide the square wave voltage and produce a plurality of selectively phase differentiated square wave voltages; a switch means for selectively rectifying the phase differentiated square wave voltages; and, a phase control circuit means for selectively delaying the rectifying of the phase differentiated square wave voltages comprising means for delaying operation of the switch means proportionate to a frequency of the differentiated square wave voltages, wherein the switch means is delayed by a controlled phase delay time.
Claim 2
Dependent Claim
172 words
An assembly for cathodically protecting a structure by impressing a selective electrical potential upon the structure with high frequency switching, said impressing being selectively operable in either a constant current, a constant voltage, or an auto-potential mode, said assembly comprising: a source of an alternating voltage power signal; a switch mode power circuit means for generating a square wave voltage form the source; a power transformer having a primary side winding and a secondary side winding, the primary side winding being driven by the power circuit means, the secondary side winding having a tap to divide the square wave voltage and produce a plurality of selectively phase differentiated square wave voltages; a switch means for selectively rectifying the phase differentiated square wave voltages; and, a phase control circuit means for selectively delaying the rectifying of the phase differentiated square wave voltages comprising means for delaying operation of the switch means proportionate to a frequency of the differentiated square wave voltages, wherein the switch means is delayed by a controlled phase delay time.
Claim 3
Dependent Claim
75 words
The assembly as claimed in claim 1 further including: a current measuring circuit means for measuring an actual current form the switch means; a current comparator circuit means for comparing the measured actual current with a preselected desired current and generating a signal representative of a difference between the actual current and the desired current; and a feedback control circuit means for selectively adjusting the controlled phase delay time as a function of said difference.
Claim 4
Dependent Claim
85 words
The assembly as claimed in claim 1 further including an off potential measuring circuit means for measuring a potential of the structure during a testing period comprising a period when current to the structure is momentarily interrupted; an off potential comparator circuit means for comparing the measured potential of the structure with a preselected desired potential and generating an off-potential difference signal; said feedback control circuit means selectively adjusting the controlled phase delay time of synchronous switches in proportion to the off potential difference signal.
Claim 5
Dependent Claim
73 words
The assembly as claimed in claim 1 further including: a voltage measuring circuit means for measuring a voltage from the switch means; a voltage comparator circuit means for comparing the measured voltage with a preselected desired voltage and generating a signal representative of a difference between the measured voltage and the desired voltage; and, a feedback control circuit means for selectively adjusting the controlled phase delay time as a function of said difference.
Claim 6
Dependent Claim
32 words
The assembly as claimed in claim 1 further including circuitry whereby said assembly is adapted to be arranged in at least one of a series or parallel configuration with other identical assemblies.
Claim 7
Dependent Claim
16 words
The assembly as claimed in claim 1 wherein the high frequency is above commercial line frequency.
Claim 8
Independent Claim
99 words
A method for selectively adjusting the energy impressed on a structure by a cathodic protection system comprising the steps of: rectifying a conventionally available energy signal with a high frequency switch-mode power circuit and a synchronous detector switch assembly; impressing the rectified signal on the structure; measuring a parameter representative of the impressed energy and generating a control signal representative of a difference with the measured energy and a desired energy; and, adjusting a timing operation of the switch assembly to selectively adjust the rectified signal whereby the adjusted rectified signal substantially impresses the desired energy on the structure.
Claim 9
Independent Claim
99 words
A method for selectively adjusting the energy impressed on a structure by a cathodic protection system comprising the steps of: rectifying a conventionally available energy signal with a high frequency switch-mode power circuit and a synchronous detector switch assembly; impressing the rectified signal on the structure; measuring a parameter representative of the impressed energy and generating a control signal representative of a difference with the measured energy and a desired energy; and, adjusting a timing operation of the switch assembly to selectively adjust the rectified signal whereby the adjusted rectified signal substantially impresses the desired energy on the structure.
Claim 10
Dependent Claim
42 words
The method of claim 7 wherein the desired energy comprises a preselected constant voltage impressed on the structure, the measuring comprising measuring the voltage from the switch assembly and adjusting the switch assembly operation to maintain a constant voltage to the structure.
Claim 11
Dependent Claim
42 words
The method of claim 8 wherein the desired energy comprises a preselected constant current from the switch means, the measuring comprising measuring the current from the switch assembly and adjusting the switch assembly operation to maintain a constant current to the structure.
Claim 12
Dependent Claim
50 words
The method of claim 7 wherein the desired energy comprises a potential of the structure, the measuring comprising measuring a potential of the structure during a testing period when the impression of energy on the structure is momentarily interrupted, and adjusting the switch assembly operation to provide the desired potential.
Claim 13
Dependent Claim
26 words
The method of claim 7 further including the step of: interconnecting a plurality of said assembly in at least one of a series or parallel configuration.
Claim 14
Dependent Claim
115 words
An off-potential method for selectively adjusting the energy impressed on a structure by a cathodic protection system having a high frequency switch mode power circuit and a synchronous detector switch assembly comprising the steps of: supplying an energy signal to the structure; selectively halting the supply of energy for a preselected period of time including switching the energy signal to obtain opposite phased signals and adding the signals to produce a zero signal; measuring the potential difference between the structure and a reference cell during the preselected period, the measuring being substantially I-R drop free; comparing the measured potential difference with a preselected desired potential level; and, adjusting the supplied energy in a preselected manner.
Claim 15
Dependent Claim
115 words
An off-potential method for selectively adjusting the energy impressed on a structure by a cathodic protection system having a high frequency switch mode power circuit and a synchronous detector switch assembly comprising the steps of: supplying an energy signal to the structure; selectively halting the supply of energy for a preselected period of time including switching the energy signal to obtain opposite phased signals and adding the signals to produce a zero signal; measuring the potential difference between the structure and a reference cell during the preselected period, the measuring being substantially I-R drop free; comparing the measured potential difference with a preselected desired potential level; and, adjusting the supplied energy in a preselected manner.
Claim 16
Dependent Claim
32 words
The method of claim 12 wherein a plurality of the measured potential differences are selectively stored and averaged, the comparing comprising comparing an averaged potential difference signal wit the desired potential level.
Claim 17
Dependent Claim
61 words
The method of claim 12 wherein the supply of energy has an alternating current power line frequency and further including the steps of: synchronizing the halting of the supply of energy to the power line frequency with zero cross-over point; and, measuring at least two I-R drop free potential differences on alternate power supply frequency cycles for minimizing power supply interference.
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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) | 1994-12-30 | 1995-07-01 | 1995-12-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-12-30 | 1999-07-01 | 1999-12-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-12-30 | 2003-07-01 | 2003-12-31 | $7700.00 | Window Closed / Lapsed |