US3855528A
Expired / Lapsed
US
⏱️ 0.0 years remaining
D-c current measuring circuit
Assignee: Lorain Products Corp
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Filing: 1973-04-06
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Granted: 1974-12-17
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Expires: 1993-04-06
Abstract
Abstract A measuring circuit for indicating the magnitude of d-c current flow through an associated circuit or conductor while maintaining electrical isolation therefrom. The measuring circuit includes a voltage generating circuit for generating first and second chopped d-c voltages and a magnetic amplifier comprising first and second cores, first and second gate windings, a control winding and first and second input or command windings. The current to be measured is passed through the command winding to control the current which the voltage generating circuit applies to the control winding through the gate windings. The measuring circuit exhibits a plurality of equilibrium conditions in each of which the magnitude of the control current flow is determined by the magnitude of the input current, thus causing the control current flow to be a continuous d-c output indication of d-c input current.
Inventors
- 👤 H Brown
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 05:10
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/18; G01R19/20; H; H03; H03F; H03F3/00; H03F3/38; H03F3/387
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
184 words
In a circuit for establishing a current indication which varies in accordance with the magnitude of a d-c command current, in combination, first and second saturable cores each having a gate winding and a command winding, a control winding linking said first and second cores, means for connecting said command windings in series, means for connecting first respective ends of said gate windings, means for connecting a first end of said control winding to said connected ends of said gate windings, a first path for conducting current flow through either of said gate windings and through said control winding, a second path for conducting a circulating current through said control winding when no appreciable current flows through either of said gate windings, current indicating means for indicating the amplitude of current flow through said control winding, means for connecting said current indicating means to said control winding, and means for applying a chopped d-c voltage to the second end of one of said gate windings and for applying a complementary chopped d-c voltage to the second end of the other of said gate windings.
Claim 2
Dependent Claim
184 words
In a circuit for establishing a current indication which varies in accordance with the magnitude of a d-c command current, in combination, first and second saturable cores each having a gate winding and a command winding, a control winding linking said first and second cores, means for connecting said command windings in series, means for connecting first respective ends of said gate windings, means for connecting a first end of said control winding to said connected ends of said gate windings, a first path for conducting current flow through either of said gate windings and through said control winding, a second path for conducting a circulating current through said control winding when no appreciable current flows through either of said gate windings, current indicating means for indicating the amplitude of current flow through said control winding, means for connecting said current indicating means to said control winding, and means for applying a chopped d-c voltage to the second end of one of said gate windings and for applying a complementary chopped d-c voltage to the second end of the other of said gate windings.
Claim 3
Dependent Claim
17 words
A circuit as set forth in claim 1 in which said second path includes unidirectional conducting means.
Claim 4
Dependent Claim
32 words
A circuit as set forth in claim 1 including clampinG means for providing a path for residual current flow through said gate windings upon interruption of current flow through said gate windings.
Claim 5
Dependent Claim
21 words
A circuit as set forth in claim 1 including means for absorbing the no-load exciting current flowing through said gate windings.
Claim 6
Dependent Claim
21 words
A circuit as set forth in claim 1 including means for absorbing the no-load exciting current flowing through said control winding.
Claim 7
Dependent Claim
181 words
In a circuit for establishing a current indication which varies in accordance with the magnitude of a d-c command current, in combination, voltage generating means having first and second outputs, said voltage generating means serving to alternately and severally apply a d-c voltage between a circuit common and said first and second outputs, first and second saturable cores each having a command winding and a gate winding, a control winding linking said first and second cores, means for connecting said command windings in series, means for connecting one end of each of said gate windings to a respective output of said voltage generating means, means for connecting together the other ends of said gate windings, means for connecting said control winding between said circuit common and the connected ends of said gate windings, unidirectional conducting means, means for connecting said unidirectional conducting means across said control winding to conduct current through said control winding when no appreciable current flows through either of said gate windings, and means for providing a current indication in accordance with the current in said control winding.
Claim 8
Dependent Claim
181 words
In a circuit for establishing a current indication which varies in accordance with the magnitude of a d-c command current, in combination, voltage generating means having first and second outputs, said voltage generating means serving to alternately and severally apply a d-c voltage between a circuit common and said first and second outputs, first and second saturable cores each having a command winding and a gate winding, a control winding linking said first and second cores, means for connecting said command windings in series, means for connecting one end of each of said gate windings to a respective output of said voltage generating means, means for connecting together the other ends of said gate windings, means for connecting said control winding between said circuit common and the connected ends of said gate windings, unidirectional conducting means, means for connecting said unidirectional conducting means across said control winding to conduct current through said control winding when no appreciable current flows through either of said gate windings, and means for providing a current indication in accordance with the current in said control winding.
Claim 9
Dependent Claim
42 words
A circuit as set forth in claim 6 including first and second clamping diodes, means for connecting said first clamping diode to one of said gate windings and means for connecting said second clamping diode to the other of said gate windings.
Claim 10
Dependent Claim
40 words
A circuit as set forth in claim 6 including a first current source for drawing a predetermined substantially constant current from said gate windings and means for connecting said first current source to the connected ends of said gate windings.
Claim 11
Dependent Claim
36 words
A circuit as set forth in claim 6 including a second current source for drawing a predetermined substantially constant current from said control winding and means for connecting said second current source to said control winding.
Claim 12
Dependent Claim
26 words
A circuit as set forth in claim 6 in which said command windings and said control winding are arranged to produce opposing fluxes in said cores.
Claim 13
Dependent Claim
48 words
A circuit as set forth in claim 6 in which said control winding is so arranged with respect to said cores that changes in the flux in one of said cores are accompanied by approximately equal but opposite changes in the flux in the other of said cores.
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) | 1977-12-16 | 1978-06-17 | 1978-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-16 | 1982-06-17 | 1982-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-16 | 1986-06-17 | 1986-12-17 | $7700.00 | Window Closed / Lapsed |