US4980794A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electromagnetic contactor with lightweight wide range current transducer with sintered powdered metal core
Assignee: Westinghouse Electric Corp
•
Filing: 1989-04-20
•
Granted: 1990-12-25
•
Expires: 2009-04-20
Abstract
Abstract A motor controller or contactor is disclosed which utilizes a non-saturating current transformer for sensing the amount of current flowing in the electrical conductor connected to the contactor. The current sensor is made of homogeneous sintered powdered metal having evenly distributed microscopic air gaps therein which increase the reluctance of the magnetic circuit but resist the influence of stray magnetic flux. This increased reluctance prevents magnetic saturation over a wide range of input current and allows the secondary of the transducer to produce a voltage which is proportional to the derivative of the primary current, that is the current being sensed by the transducer. The aforementioned voltage is linearly proportional to the derivative of the current over a wide range of primary current values. This voltage is integrated to produce an output signal which is directly proportional to the aforementioned primary current over the wide range of current values. By measuring only the derivative of the primary current, the current transducer can be significantly smaller than an equivalent current transformer. The homogenous magnetic core of powdered metal and interposed air gaps has a Rayleigh Constant lambda of such value lambda H is significantly less than the initial permeability less than the initial permeability mu o of the core, thus allowing the transformer to sense current over a wide range.
Inventors
- 👤 Joseph C. Engel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:33
CPC Classifications
H; H01; H01F; H01F29/00; H01F29/08; H01F29/10; G; G01; G01R; G01R15/00; G01R15/14; G01R15/18; G01R15/183; H01F27/00; H01F27/24; H01F27/255; H01F3/00; H01F3/10; H01F3/14
Claims Analysis
Total Claims: 65
Claim 1
Independent Claim
208 words
Motor control apparatus of the kind which performs a motor control operation as a function of motor current, comprising: a current-to-voltage transducer, comprising: homogeneous magnetic core means; primary winding means disposed to electromagnetically interact with said homogeneous magnetic core means for providing magnetic flux in said homogeneous magnetic core means in general proportion to the amount of electrical current I flowing in said primary winding means for values of said electrical current I within a given range of current I; homogeneous magnetic core means comprising powdered metal and interposed microscopic air gaps characterized by a Rayleigh Constant λ of such magnitude that a value λH is significantly less than the initial permeability μo of the homogeneous magnetic core means, thus causing the relationship: ##EQU16## for said entire range of Current I, where H Equals the electromagnetic field strength attributable to said magnetic flux; secondary winding means disposed on said homogeneous magnetic core means for providing an electrical voltage V at the output terminals thereof which is generally approximately proportional to the first derivative of said current I with respect to time for said entire range of current I; and voltage sensitive means disposed to receive said electrical voltage V and to provide said control operation in response thereto.
Claim 2
Dependent Claim
208 words
Motor control apparatus of the kind which performs a motor control operation as a function of motor current, comprising: a current-to-voltage transducer, comprising: homogeneous magnetic core means; primary winding means disposed to electromagnetically interact with said homogeneous magnetic core means for providing magnetic flux in said homogeneous magnetic core means in general proportion to the amount of electrical current I flowing in said primary winding means for values of said electrical current I within a given range of current I; homogeneous magnetic core means comprising powdered metal and interposed microscopic air gaps characterized by a Rayleigh Constant λ of such magnitude that a value λH is significantly less than the initial permeability μo of the homogeneous magnetic core means, thus causing the relationship: ##EQU16## for said entire range of Current I, where H Equals the electromagnetic field strength attributable to said magnetic flux; secondary winding means disposed on said homogeneous magnetic core means for providing an electrical voltage V at the output terminals thereof which is generally approximately proportional to the first derivative of said current I with respect to time for said entire range of current I; and voltage sensitive means disposed to receive said electrical voltage V and to provide said control operation in response thereto.
Claim 3
Dependent Claim
16 words
The combination as claimed in claim 1 wherein said primary winding means comprises a single turn.
Claim 4
Dependent Claim
13 words
The combination as claimed in claim 1 wherein said powdered metal comprises ferrite.
Claim 5
Dependent Claim
13 words
The combination as claimed in claim 1 wherein said powdered metal is sintered.
Claim 6
Dependent Claim
16 words
The combination as claimed in claim 1 wherein said electrical current I is said motor current.
Claim 7
Dependent Claim
12 words
The combination as claimed in claim 1, wherein said metal comprises iron.
Claim 8
Dependent Claim
53 words
The combination as claimed in claim 1, wherein the relationship of λH to μo is such that the contribution to the change in voltage V related to the value: ##EQU17## varies over said range of current I by ≦1% of the contribution to the change in voltage V related to the value: ##EQU18##
Claim 9
Dependent Claim
204 words
A contactor of the kind which opens and closes an electrical circuit, comprising: a current-to-voltage transducer, comprising: homogeneous magnetic core means; primary winding means disposed to electromagnetically interact with said homogeneous magnetic core means for providing magnetic flux in said homogeneous magnetic core means in general proportion to the amount of electrical current I flowing in said primary winding means for values of said electrical current I within a given range of current I; homogeneous magnetic core means comprising powdered metal and interposed microscopic air gaps characterized by a Rayleigh Constant λ of such magnitude that a value λH is significantly less than the initial permeability μo of the homogeneous magnetic core means, thus causing the relationship: ##EQU19## for said entire range of Current I, where H Equals the electromagnetic field strength attributable to said magnetic flux; secondary winding means disposed on said homogeneous magnetic core means for providing an electrical voltage V at the output terminals thereof which is generally approximately proportional to the first derivative of said current I with respect to time for said entire range of current I; and voltage sensitive means disposed to receive said electrical voltage V and to open said electrical circuit when required in response thereto.
Claim 10
Dependent Claim
204 words
A contactor of the kind which opens and closes an electrical circuit, comprising: a current-to-voltage transducer, comprising: homogeneous magnetic core means; primary winding means disposed to electromagnetically interact with said homogeneous magnetic core means for providing magnetic flux in said homogeneous magnetic core means in general proportion to the amount of electrical current I flowing in said primary winding means for values of said electrical current I within a given range of current I; homogeneous magnetic core means comprising powdered metal and interposed microscopic air gaps characterized by a Rayleigh Constant λ of such magnitude that a value λH is significantly less than the initial permeability μo of the homogeneous magnetic core means, thus causing the relationship: ##EQU19## for said entire range of Current I, where H Equals the electromagnetic field strength attributable to said magnetic flux; secondary winding means disposed on said homogeneous magnetic core means for providing an electrical voltage V at the output terminals thereof which is generally approximately proportional to the first derivative of said current I with respect to time for said entire range of current I; and voltage sensitive means disposed to receive said electrical voltage V and to open said electrical circuit when required in response thereto.
Claim 11
Dependent Claim
16 words
The combination as claimed in claim 8 wherein said primary winding means comprises a single turn.
Claim 12
Dependent Claim
13 words
The combination as claimed in claim 8 wherein said powdered metal comprises ferrite.
Claim 13
Dependent Claim
13 words
The combination as claimed in claim 8 wherein said powdered metal is sintered.
Claim 14
Dependent Claim
20 words
The combination as claimed in claim 8 wherein said electrical current I is current which flows in said electrical circuit.
Claim 15
Dependent Claim
12 words
The combination as claimed in claim 8, wherein said metal comprises iron.
Claim 16
Dependent Claim
53 words
The combination as claimed in claim 8, wherein the relationship of λH to μo is such that the contribution to the change in voltage V related to the value: ##EQU20## varies over said range of current I by ≦1% of the contribution to the change in voltage V related to the value: ##EQU21##
Claim 17
Dependent Claim
173 words
A current-to-voltage transducer, comprising: homogeneous magnetic core means; primary winding means disposed to electromagnetically interact with said homogeneous magnetic core means for providing magnetic flux in said homogeneous magnetic core means in general proportion to the amount of electrical current I flowing in said primary winding means for values of said electrical current I within a given range of current I; said homogeneous magnetic core means comprising generally homogeneously dispersed magnetic regions and non-magnetic regions therein characterized by a Rayleigh Constant λ of such magnitude that a value λH is significantly less than the initial permeability μo of the homogeneous magnetic core means, thus causing the relationship: ##EQU22## for said entire range of Current I, where H Equals the electromagnetic field strength attributable to said magnetic flux; and secondary winding means disposed on said homogeneous magnetic core means for providing an electrical voltage V at the output terminals thereof which is generally approximately proportional to the first derivative of said current I with respect to time for said entire range of current I.
Claim 18
Dependent Claim
173 words
A current-to-voltage transducer, comprising: homogeneous magnetic core means; primary winding means disposed to electromagnetically interact with said homogeneous magnetic core means for providing magnetic flux in said homogeneous magnetic core means in general proportion to the amount of electrical current I flowing in said primary winding means for values of said electrical current I within a given range of current I; said homogeneous magnetic core means comprising generally homogeneously dispersed magnetic regions and non-magnetic regions therein characterized by a Rayleigh Constant λ of such magnitude that a value λH is significantly less than the initial permeability μo of the homogeneous magnetic core means, thus causing the relationship: ##EQU22## for said entire range of Current I, where H Equals the electromagnetic field strength attributable to said magnetic flux; and secondary winding means disposed on said homogeneous magnetic core means for providing an electrical voltage V at the output terminals thereof which is generally approximately proportional to the first derivative of said current I with respect to time for said entire range of current I.
Claim 19
Dependent Claim
23 words
The combination as claimed in claim 15 wherein said magnetic core means comprises powdered metal particles separated by regions of low magnetic permeability.
Claim 20
Dependent Claim
17 words
The combination as claimed in claim 16 wherein said regions of low magnetic permeability comprise air gaps.
Claim 21
Dependent Claim
14 words
The combination as claimed in claim 15 wherein said magnetic core means is toroidal.
Claim 22
Dependent Claim
30 words
The combination as claimed in claim 15 wherein said total magnetic permeability is generally constant for values of said electrical current I less than or equal to said predetermined amount.
Claim 23
Dependent Claim
23 words
The combination as claimed in claim 15 wherein said voltage V is generally directly proportional to said current I when I is sinusoidal.
Claim 24
Dependent Claim
17 words
The combination as claimed in claim 15 wherein said magnetic regions and said non-magnetic regions are microscopic.
Claim 25
Dependent Claim
14 words
The combination as claimed in claim 15, wherein said magnetic regions comprise powdered iron.
Claim 26
Dependent Claim
53 words
The combination as claimed in claim 15, wherein the relationship of λH to μo is such that the contribution to the change in voltage V related to the value: ##EQU23## varies over said range of current I by ≦1% of the contribution to the change in voltage V related to the value: ##EQU24##
Claim 27
Dependent Claim
211 words
Motor control apparatus of the kind which performs a motor control operation as a function of motor current, comprising: a current-to-voltage transducer, comprising: homogeneous magnetic core means; primary winding means disposed to electromagnetically interact with said homogeneous magnetic core means for providing magnetic flux in said homogeneous magnetic core means in general proportion to the amount of electrical current I flowing in said primary winding means for values of said electrical current I within a given range of current I; said homogeneous magnetic core means comprising generally homogeneously dispersed magnetic regions and non-magnetic regions therein characterized by a Rayleigh Constant λ of such magnitude that a value λH is significantly less than the initial permeability μo of the homogeneous magnetic core means, thus causing the relationship: ##EQU25## for said entire range of Current I, where H Equals the electromagnetic field strength attributable to said magnetic flux; secondary winding means disposed on said homogeneous magnetic core means for providing an electrical voltage V at the output terminals thereof which is generally approximately proportional to the first derivative of said current I with respect to time for said entire range of current I; and voltage sensitive means disposed to receive said electrical voltage V and to provide said control operation in response thereto.
Claim 28
Dependent Claim
211 words
Motor control apparatus of the kind which performs a motor control operation as a function of motor current, comprising: a current-to-voltage transducer, comprising: homogeneous magnetic core means; primary winding means disposed to electromagnetically interact with said homogeneous magnetic core means for providing magnetic flux in said homogeneous magnetic core means in general proportion to the amount of electrical current I flowing in said primary winding means for values of said electrical current I within a given range of current I; said homogeneous magnetic core means comprising generally homogeneously dispersed magnetic regions and non-magnetic regions therein characterized by a Rayleigh Constant λ of such magnitude that a value λH is significantly less than the initial permeability μo of the homogeneous magnetic core means, thus causing the relationship: ##EQU25## for said entire range of Current I, where H Equals the electromagnetic field strength attributable to said magnetic flux; secondary winding means disposed on said homogeneous magnetic core means for providing an electrical voltage V at the output terminals thereof which is generally approximately proportional to the first derivative of said current I with respect to time for said entire range of current I; and voltage sensitive means disposed to receive said electrical voltage V and to provide said control operation in response thereto.
Claim 29
Dependent Claim
23 words
The combination as claimed in claim 24 wherein said magnetic core means comprises powdered metal particles separated by regions of low magnetic permeability.
Claim 30
Dependent Claim
17 words
The combination as claimed in claim 25 wherein said regions of low magnetic permeability comprise air gaps.
Claim 31
Dependent Claim
14 words
The combination as claimed in claim 24 wherein said magnetic core means is toroidal.
Claim 32
Dependent Claim
30 words
The combination as claimed in claim 24 wherein said total magnetic permeability is generally constant for values of said electrical current I less than or equal to said predetermined amount.
Claim 33
Dependent Claim
23 words
The combination as claimed in claim 24 wherein said voltage V is generally directly proportional to said current I when I is sinusoidal.
Claim 34
Dependent Claim
17 words
The combination as claimed in claim 24 wherein said magnetic regions and said non-magnetic regions are microscopic.
Claim 35
Dependent Claim
16 words
The combination as claimed in claim 24 wherein said electrical current I is said motor current.
Claim 36
Dependent Claim
14 words
The combination as claimed in claim 24, wherein said magnetic regions comprise powdered iron.
Claim 37
Dependent Claim
53 words
The combination as claimed in claim 24, wherein the relationship of λH to μo is such that the contribution to the change in voltage V related to the value: ##EQU26## varies over said range of current I by ≦1% of the contribution to the change in voltage V related to the value: ##EQU27##
Claim 38
Dependent Claim
207 words
A contactor of the kind which opens and closes an electrical circuit, comprising: a current-to-voltage transducer, comprising: homogeneous magnetic core means; primary winding means disposed to electromagnetically interact with said homogeneous magnetic core means for providing magnetic flux in said homogeneous magnetic core means in general proportion to the amount of electrical current I flowing in said primary winding means for values of said electrical current I within a given range of current I; said homogeneous magnetic core means comprising generally homogeneously dispersed magnetic regions and non-magnetic regions therein characterized by a Rayleigh Constant λ of such magnitude that a value λH is significantly less than the initial permeability μo of the homogeneous magnetic core means, thus causing the relationship: ##EQU28## for said entire range of Current I, where H Equals the electromagnetic field strength attributable to said magnetic flux; secondary winding means disposed on said homogeneous magnetic core means for providing an electrical voltage V at the output terminals thereof which is generally approximately proportional to the first derivative of said current I with respect to time for said entire range of current I; and voltage sensitive means disposed to receive said electrical voltage V and to open said electrical circuit when required in response thereto.
Claim 39
Dependent Claim
207 words
A contactor of the kind which opens and closes an electrical circuit, comprising: a current-to-voltage transducer, comprising: homogeneous magnetic core means; primary winding means disposed to electromagnetically interact with said homogeneous magnetic core means for providing magnetic flux in said homogeneous magnetic core means in general proportion to the amount of electrical current I flowing in said primary winding means for values of said electrical current I within a given range of current I; said homogeneous magnetic core means comprising generally homogeneously dispersed magnetic regions and non-magnetic regions therein characterized by a Rayleigh Constant λ of such magnitude that a value λH is significantly less than the initial permeability μo of the homogeneous magnetic core means, thus causing the relationship: ##EQU28## for said entire range of Current I, where H Equals the electromagnetic field strength attributable to said magnetic flux; secondary winding means disposed on said homogeneous magnetic core means for providing an electrical voltage V at the output terminals thereof which is generally approximately proportional to the first derivative of said current I with respect to time for said entire range of current I; and voltage sensitive means disposed to receive said electrical voltage V and to open said electrical circuit when required in response thereto.
Claim 40
Dependent Claim
23 words
The combination as claimed in claim 34 wherein said magnetic core means comprises powdered metal particles separated by regions of low magnetic permeability.
Claim 41
Dependent Claim
17 words
The combination as claimed in claim 35 wherein said regions of low magnetic permeability comprise air gaps.
Claim 42
Dependent Claim
14 words
The combination as claimed in claim 34 wherein said magnetic core means is toroidal.
Claim 43
Dependent Claim
30 words
The combination as claimed in claim 34 wherein said total magnetic permeability is generally constant for values of said electrical current I less than or equal to said predetermined amount.
Claim 44
Dependent Claim
23 words
The combination as claimed in claim 34 wherein said voltage V is generally directly proportional to said current I when I is sinusoidal.
Claim 45
Dependent Claim
17 words
The combination as claimed in claim 34 wherein said magnetic regions and said non-magnetic regions are microscopic.
Claim 46
Dependent Claim
22 words
The combination as claimed in claim 34 wherein said electrical current I is said motor current which flows in said electrical circuit.
Claim 47
Dependent Claim
53 words
The combination as claimed in claim 34, wherein the relationship of λH is μo is such that the contribution to the change in voltage V related to the value: ##EQU29## varies over said range of current I by ≦1% of the contribution to the change in voltage V related to the value: ##EQU30##
Claim 48
Dependent Claim
212 words
Motor control apparatus of the kind which performs a function in response to the flow of electrical current I, comprising: a current-to-voltage transducer, comprising: homogeneous magnetic core means; primary winding means disposed to electromagnetically interact with said homogeneous magnetic core means for providing magnetic flux in said homogeneous magnetic core means in general proportion to the amount of said electrical current I flowing in said primary winding means for values of said electrical current I within a given range of current I; said homogeneous magnetic core means comprising generally homogeneously dispersed magnetic regions and non-magnetic regions therein characterized by a Rayleigh Constant λ of such magnitude that a value λH is significantly less than the initial permeability μo of the homogeneous magnetic core means, thus causing the relationship: ##EQU31## for said entire range of Current I, where H Equals the electromagnetic field strength attributable to said magnetic flux; secondary winding means disposed on said homogeneous magnetic core means for providing an electrical voltage V at the output terminals thereof which is generally approximately proportional to the first derivative of said current I with respect to time for said entire range of current I; and voltage sensitive means disposed to receive said electrical voltage V and to provide said function in response thereto.
Claim 49
Dependent Claim
212 words
Motor control apparatus of the kind which performs a function in response to the flow of electrical current I, comprising: a current-to-voltage transducer, comprising: homogeneous magnetic core means; primary winding means disposed to electromagnetically interact with said homogeneous magnetic core means for providing magnetic flux in said homogeneous magnetic core means in general proportion to the amount of said electrical current I flowing in said primary winding means for values of said electrical current I within a given range of current I; said homogeneous magnetic core means comprising generally homogeneously dispersed magnetic regions and non-magnetic regions therein characterized by a Rayleigh Constant λ of such magnitude that a value λH is significantly less than the initial permeability μo of the homogeneous magnetic core means, thus causing the relationship: ##EQU31## for said entire range of Current I, where H Equals the electromagnetic field strength attributable to said magnetic flux; secondary winding means disposed on said homogeneous magnetic core means for providing an electrical voltage V at the output terminals thereof which is generally approximately proportional to the first derivative of said current I with respect to time for said entire range of current I; and voltage sensitive means disposed to receive said electrical voltage V and to provide said function in response thereto.
Claim 50
Dependent Claim
23 words
The combination as claimed in claim 43 wherein said magnetic core means comprises powdered metal particles separated by regions of low magnetic permeability.
Claim 51
Dependent Claim
17 words
The combination as claimed in claim 44 wherein said regions of low magnetic permeability comprise air gaps.
Claim 52
Dependent Claim
14 words
The combination as claimed in claim 43 wherein said magnetic core means is toroidal.
Claim 53
Dependent Claim
30 words
The combination as claimed in claim 43 wherein said total magnetic permeability is generally constant for values of said electrical current I less than or equal to said predetermined amount.
Claim 54
Dependent Claim
23 words
The combination as claimed in claim 43 wherein said voltage V is generally directly proportional to said current I when I is sinusoidal.
Claim 55
Dependent Claim
17 words
The combination as claimed in claim 43 wherein said magnetic regions and said non-magnetic regions are microscopic.
Claim 56
Dependent Claim
53 words
The combination as claimed in claim 43, wherein the relationship of λH to μo is such that the contribution to the change in voltage V related to the value: ##EQU32## varies over said range of current I by ≦1% of the contribution to the change in voltage V related to the value: ##EQU33##
Claim 57
Dependent Claim
213 words
An electrical meter of the kind which performs a meter function in response to the flow of electrical current I, comprising: a current-to-voltage transducer, comprising: homogeneous magnetic core means; primary winding means disposed to electromagnetically interact with said homogeneous magnetic core means for providing magnetic flux in said homogeneous magnetic core means in general proportion to the amount of electrical current I flowing in said primary winding means for values of said electrical current I within a given range of current I; said homogeneous magnetic core means comprising generally homogeneously dispersed magnetic regions and non-magnetic regions therein characterized by a Rayleigh Constant λ of such magnitude that a value λH is significantly less than the initial permeability μo of the homogeneous magnetic core means, thus causing the relationship: ##EQU34## for said entire range of Current I, where H Equals the electromagnetic field strength attributable to said magnetic flux; secondary winding means disposed on said homogeneous magnetic core means for providing an electrical voltage V at the output terminals thereof which is generally approximately proportional to the first derivative of said current I with respect to time for said entire range of current I; and voltage sensitive means disposed to receive said electrical voltage V and to provide said meter function in response thereto.
Claim 58
Dependent Claim
213 words
An electrical meter of the kind which performs a meter function in response to the flow of electrical current I, comprising: a current-to-voltage transducer, comprising: homogeneous magnetic core means; primary winding means disposed to electromagnetically interact with said homogeneous magnetic core means for providing magnetic flux in said homogeneous magnetic core means in general proportion to the amount of electrical current I flowing in said primary winding means for values of said electrical current I within a given range of current I; said homogeneous magnetic core means comprising generally homogeneously dispersed magnetic regions and non-magnetic regions therein characterized by a Rayleigh Constant λ of such magnitude that a value λH is significantly less than the initial permeability μo of the homogeneous magnetic core means, thus causing the relationship: ##EQU34## for said entire range of Current I, where H Equals the electromagnetic field strength attributable to said magnetic flux; secondary winding means disposed on said homogeneous magnetic core means for providing an electrical voltage V at the output terminals thereof which is generally approximately proportional to the first derivative of said current I with respect to time for said entire range of current I; and voltage sensitive means disposed to receive said electrical voltage V and to provide said meter function in response thereto.
Claim 59
Dependent Claim
23 words
The combination as claimed in claim 51 wherein said magnetic core means comprises powdered metal particles separated by regions of low magnetic permeability.
Claim 60
Dependent Claim
17 words
The combination as claimed in claim 52 wherein said regions of low magnetic permeability comprise air gaps.
Claim 61
Dependent Claim
14 words
The combination as claimed in claim 51 wherein said magnetic core means is toroidal.
Claim 62
Dependent Claim
30 words
The combination as claimed in claim 51 wherein said total magnetic permeability is generally constant for values of said electrical current I less than or equal to said predetermined amount.
Claim 63
Dependent Claim
23 words
The combination as claimed in claim 51 wherein said voltage V is generally directly proportional to said current I when I is sinusoidal.
Claim 64
Dependent Claim
17 words
The combination as claimed in claim 51 wherein said magnetic regions and said non-magnetic regions are microscopic.
Claim 65
Dependent Claim
53 words
The combination as claimed in claim 51, wherein the relationship of λH is μo is such that the contribution to the change in voltage V related to the value: ##EQU35## varies over said range of current I by ≦1% of the contribution to the change in voltage V related to the value: ##EQU36##
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) | 1993-12-24 | 1994-06-25 | 1994-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-24 | 1998-06-25 | 1998-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-24 | 2002-06-25 | 2002-12-25 | $7700.00 | Window Closed / Lapsed |