CA1245254A - High speed contact driver for circuit interruption device - Google Patents
High speed contact driver for circuit interruption deviceInfo
- Publication number
- CA1245254A CA1245254A CA000500260A CA500260A CA1245254A CA 1245254 A CA1245254 A CA 1245254A CA 000500260 A CA000500260 A CA 000500260A CA 500260 A CA500260 A CA 500260A CA 1245254 A CA1245254 A CA 1245254A
- Authority
- CA
- Canada
- Prior art keywords
- conductors
- contact
- high speed
- driver
- bridging
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Abstract
HIGH SPEED CONTACT DRIVER
FOR CIRCUIT INTERRUPTION DEVICE
Abstract of the Disclosure A bridging contact is arranged across two fixed contacts with a pair of parallel, closely spaced conductors serving as the bridging contact carrier. A
high current pulse in opposite direction within the parallel conductors generates electrodynamic forces rapidly propelling the conductors further apart. The bridging contact carried by the parallel conductors is rapidly driven out of contact relation with the fixed contacts to interrupt the circuit.
FOR CIRCUIT INTERRUPTION DEVICE
Abstract of the Disclosure A bridging contact is arranged across two fixed contacts with a pair of parallel, closely spaced conductors serving as the bridging contact carrier. A
high current pulse in opposite direction within the parallel conductors generates electrodynamic forces rapidly propelling the conductors further apart. The bridging contact carried by the parallel conductors is rapidly driven out of contact relation with the fixed contacts to interrupt the circuit.
Description
~2~SZ~
HIGH SPEE~ CONTACT DRIVER
FOR CIRCUIT INTERRUPTION DEVICE
Backqround of the Invention The advent of a practical solid state current limiting interrupter such as described in Canadian Application Serial No. 478,410, filed April 4, 1985 in the name of E.K. Howell has provided a synergistic relationship between the circuit interrupter contacts and the contact operating mechanism. By employing a solid state switch in parallel with the contacts, the current is diverted away Erom the contacts immediately upon contact separation to substantially reduce the arcing energy and hence essentially eliminate the deleterious arcing effect on the contacts. This in turn allows the contacts to be made much smaller and hence reduces both their thermal and inertial mass. ~'he reduction in the inertial mass in turn allows the contacts to be more rapidly separated and hence allows circuit interruption during the early stages of the current waveform. The lower contact inertial mass allows the use of a bridging contact between a pair of fixed contacts such as described in U.S. Patent No.
4,598,1~7, issued July 1, 19~6, entitled "Current Limiting Circuit Breaker" in the name of E.K. Howell.
The bridging contact arrangement provides for a further reduction in the mass of the contacts such that even more rapid contact separation can be attained and allows the current interruption to occur at the correspondingly earlier stages of the current waveform.
~' ~ 5~
HIGH SPEE~ CONTACT DRIVER
FOR CIRCUIT INTERRUPTION DEVICE
Backqround of the Invention The advent of a practical solid state current limiting interrupter such as described in Canadian Application Serial No. 478,410, filed April 4, 1985 in the name of E.K. Howell has provided a synergistic relationship between the circuit interrupter contacts and the contact operating mechanism. By employing a solid state switch in parallel with the contacts, the current is diverted away Erom the contacts immediately upon contact separation to substantially reduce the arcing energy and hence essentially eliminate the deleterious arcing effect on the contacts. This in turn allows the contacts to be made much smaller and hence reduces both their thermal and inertial mass. ~'he reduction in the inertial mass in turn allows the contacts to be more rapidly separated and hence allows circuit interruption during the early stages of the current waveform. The lower contact inertial mass allows the use of a bridging contact between a pair of fixed contacts such as described in U.S. Patent No.
4,598,1~7, issued July 1, 19~6, entitled "Current Limiting Circuit Breaker" in the name of E.K. Howell.
The bridging contact arrangement provides for a further reduction in the mass of the contacts such that even more rapid contact separation can be attained and allows the current interruption to occur at the correspondingly earlier stages of the current waveform.
~' ~ 5~
- 2 - 41PS 6306 The aforementioned Canadian Application Serial No. 478,410 and U.S. Patent No.
should be reviewed for a good description of the operation of a solid state switch for circuit interruption as well as for describing the configuration of a bridging electrode arranyement.
The instant invention is directed toward a high speed contact driver for rapidly separating bridging contacts from a pair of fixed contacts such as described in the aforementioned U.S. Patent No~ .
U.S. Patent No. 3,215,796, issued November 2, 1965 in the name of Bruno Leisi, discloses the idea of utilizing line current to induce current in a current loop including closely spaced parallel conduetors to drive the conductors apart and to separate movable contacts from associated Eixed contacts.
U.S. Patent No. 3,168,626, issued February 2, 1965 in the name of Richard Patrick, discloses a fuse utilizing the repulsive forees developed by fault eurrents flowing in opposite directions through closely spaced, parallel fuse links to sever one or both links and thus interrupt the faulted circuit.
U.S. Patent No. 3,002,065, issued September 26, 1961 in the name of John LaTour, Jr., discloses the use of excessive line eurrents flowing in opposite direetion through conductive columns to repulse one of the columns and thus provide a shunt path to protect a meter.
The purpose of the instant invention is to provide a high speed contact driver arrangement wherein a high current pulse is employed to electrodynamically repulse a pair of conductors serving as a contact carrier for a bridging contact arranged across a pair of contacts within a protected circuit for extremely fast circuit interruption upon eommand.
Summary of *he Invention The invention eomprises a high speed eontaet
should be reviewed for a good description of the operation of a solid state switch for circuit interruption as well as for describing the configuration of a bridging electrode arranyement.
The instant invention is directed toward a high speed contact driver for rapidly separating bridging contacts from a pair of fixed contacts such as described in the aforementioned U.S. Patent No~ .
U.S. Patent No. 3,215,796, issued November 2, 1965 in the name of Bruno Leisi, discloses the idea of utilizing line current to induce current in a current loop including closely spaced parallel conduetors to drive the conductors apart and to separate movable contacts from associated Eixed contacts.
U.S. Patent No. 3,168,626, issued February 2, 1965 in the name of Richard Patrick, discloses a fuse utilizing the repulsive forees developed by fault eurrents flowing in opposite directions through closely spaced, parallel fuse links to sever one or both links and thus interrupt the faulted circuit.
U.S. Patent No. 3,002,065, issued September 26, 1961 in the name of John LaTour, Jr., discloses the use of excessive line eurrents flowing in opposite direetion through conductive columns to repulse one of the columns and thus provide a shunt path to protect a meter.
The purpose of the instant invention is to provide a high speed contact driver arrangement wherein a high current pulse is employed to electrodynamically repulse a pair of conductors serving as a contact carrier for a bridging contact arranged across a pair of contacts within a protected circuit for extremely fast circuit interruption upon eommand.
Summary of *he Invention The invention eomprises a high speed eontaet
- 3 - 41PS 6306 driver wherein a bridging contact is resiliently supported by means of a cantilever spring and is carried by a pair of closely spaced electrical conductors. The bridging contact is biased into electrical contact relation with a pair of stationary contacts by means of a contact spring. A pulse of current applied to the conductors results in the electrodynamic repulsion of the conductors and the lifting of the bridging contact away from the stationary contacts against the bias of the contact spring.
Brief De'scrip'tio'n'of the Drawings Fig. 1 is a plan view in partial section of the high speed contact driver according to the invention;
Figs. 2A and 2B represent plan views in partial section of the contact driver of Fig. 1 before and after excitation;
Fig. 3 is a graphic representation of the bridging contact separation force relative to the separa-tion distance between the bridging contact and the stationary contacts; and Fig. 4 is a plan view in partial section of an alternative embodiment of the high speed contact driver shown in Fig. 1.
Description'of the Preferred Embodiment An illustrative embodiment of the high speed contact driver 10 of the invention is shown in Fig. 1 wherein a pair of rigid conductors 11 r 12 each carrying a fixed contact 13, 14 are connected by means of a bridging contact 15. The bridging contact is carriedby a pair of conductors 20, 21 which are attached to the bridging contact at one end so that the bridging contact electrically connects the two conductors in series.
The opposite ends of the two conductors are respectively connected to a pair of terminal connectors 22, 23 by means of ter~inal screws 24, 25. Electrical connection is made to the two conductors by attaching a current
Brief De'scrip'tio'n'of the Drawings Fig. 1 is a plan view in partial section of the high speed contact driver according to the invention;
Figs. 2A and 2B represent plan views in partial section of the contact driver of Fig. 1 before and after excitation;
Fig. 3 is a graphic representation of the bridging contact separation force relative to the separa-tion distance between the bridging contact and the stationary contacts; and Fig. 4 is a plan view in partial section of an alternative embodiment of the high speed contact driver shown in Fig. 1.
Description'of the Preferred Embodiment An illustrative embodiment of the high speed contact driver 10 of the invention is shown in Fig. 1 wherein a pair of rigid conductors 11 r 12 each carrying a fixed contact 13, 14 are connected by means of a bridging contact 15. The bridging contact is carriedby a pair of conductors 20, 21 which are attached to the bridging contact at one end so that the bridging contact electrically connects the two conductors in series.
The opposite ends of the two conductors are respectively connected to a pair of terminal connectors 22, 23 by means of ter~inal screws 24, 25. Electrical connection is made to the two conductors by attaching a current
- 4 - 41PS 6306 source to the terminal screws. A block of insulating material 16 of a predetermined mass Ml is attached to one end oE a cantilever spring 18 by means of a screw 19 and the spring is attached to a support 17 at the opposite end by means of a separate screw. The mass M2 of the bridging contact 15, is selected to be very small with respect to the mass Ml of the insulating material.
A contact spring 26 is attaehed to the bridging contact at one end and the other end is fixedly attached to a support 27. The tension supplied by contact spring 26 is adjusted to hold the bridging contact into good electrical connection with the fixed contac-ts in opposition to the force exerted by the cantilever spring 18 on the bridging contact via the conductors 20, 21. When the lS contact driver is used within a circuit interrupter, the circuit current I2 transfers between the rigid conductors 11, 12 in the indicated direction, through the fixed contacts 13, 14 and the bridging contact 15 in the manner described in the aforementioned U.S.
~;; 20 Patent No. ~ of Howell. The length Il of the conductors 20, 21 and the separation distance dl is adjusted to ensure that a predetermined controlled current pulse Il in the indicated directions, will produce sufficient electrodynamic repulsion between the two conductors to overcome the bias provided by the contact spring 26 and to rapidly separate the bridging contact from the fixed contacts within a time increment of 10-100 microseconds from the initiation of the current pulse I1.
The current loop provided between the terminal screw 24, conductor 21, bridging contact 15, conductor 20 and terminal screw 25 is depicted at Fig. 2(a) with no current flowing through the loop and with a permanent magnetic field exerted across a central section of the conductors as outlined by the dotted rectangle 30. The substantial increase in the electrodynamic repulsion ``` ~2~52~
A contact spring 26 is attaehed to the bridging contact at one end and the other end is fixedly attached to a support 27. The tension supplied by contact spring 26 is adjusted to hold the bridging contact into good electrical connection with the fixed contac-ts in opposition to the force exerted by the cantilever spring 18 on the bridging contact via the conductors 20, 21. When the lS contact driver is used within a circuit interrupter, the circuit current I2 transfers between the rigid conductors 11, 12 in the indicated direction, through the fixed contacts 13, 14 and the bridging contact 15 in the manner described in the aforementioned U.S.
~;; 20 Patent No. ~ of Howell. The length Il of the conductors 20, 21 and the separation distance dl is adjusted to ensure that a predetermined controlled current pulse Il in the indicated directions, will produce sufficient electrodynamic repulsion between the two conductors to overcome the bias provided by the contact spring 26 and to rapidly separate the bridging contact from the fixed contacts within a time increment of 10-100 microseconds from the initiation of the current pulse I1.
The current loop provided between the terminal screw 24, conductor 21, bridging contact 15, conductor 20 and terminal screw 25 is depicted at Fig. 2(a) with no current flowing through the loop and with a permanent magnetic field exerted across a central section of the conductors as outlined by the dotted rectangle 30. The substantial increase in the electrodynamic repulsion ``` ~2~52~
- 5 - 41PS 6306 forces exerted upon the conductors by the addition of the magnetic field will be descri.bed below with reference to Fig. 3.
The effect of the electrodynamic forces represented as Fl and Fl' in the indicated directions, is shown in Fig. 2(b) for comparison to Fig. 2(a). It is noted that the separation distance d2 between the two conductors upon electrodynamic repulsion, is substantially larger than -the inltial separation distance dl and that the bridging contact 15 has separated from the fixed contact 13 by an increment dl . The large separation distance d2 is the effect of the repulsion force Fl, which is proportional to the product of current Il, times the magnetic field strength exerted by magnetic field 30. The corce on the bridging contact is represented by the force vector F2 which is exerted in the indicated direction, wlth an equal magnitude force F2' exer-ted in the opposite direction on block 16. Since the mass M2 of contact 15 is much smaller than the mass Ml of block 16, equal forces F2 and F2' will produce a much larger acceleration of contact 15 than of block 16. Thus in the 100 microsecond time frame, block 16 remains essentially stationary.
The variation i.n the force F2 on the bridging contact as a function of the separation distance between the bridging and the fixed contacts in the absence of permanent magnetic field 30, is shown at 28 in Fig. 3.
It is noted that the force F2 on -the bridging contact is very high initially, in the order of one hundred pounds, to provide a high acceleration when the current pulse Il is first applied and decreases rapidly as the bridging contact 15 becomes separated from the fixed contacts 13, 14 and the separation distance increases from zero to a few thousandths of an inch. The effect of the permanent magnetic field 30 is shown at 29 to increase the corce exerted on the bridging contact at larger contact separation distances.
Z5~
The effect of the electrodynamic forces represented as Fl and Fl' in the indicated directions, is shown in Fig. 2(b) for comparison to Fig. 2(a). It is noted that the separation distance d2 between the two conductors upon electrodynamic repulsion, is substantially larger than -the inltial separation distance dl and that the bridging contact 15 has separated from the fixed contact 13 by an increment dl . The large separation distance d2 is the effect of the repulsion force Fl, which is proportional to the product of current Il, times the magnetic field strength exerted by magnetic field 30. The corce on the bridging contact is represented by the force vector F2 which is exerted in the indicated direction, wlth an equal magnitude force F2' exer-ted in the opposite direction on block 16. Since the mass M2 of contact 15 is much smaller than the mass Ml of block 16, equal forces F2 and F2' will produce a much larger acceleration of contact 15 than of block 16. Thus in the 100 microsecond time frame, block 16 remains essentially stationary.
The variation i.n the force F2 on the bridging contact as a function of the separation distance between the bridging and the fixed contacts in the absence of permanent magnetic field 30, is shown at 28 in Fig. 3.
It is noted that the force F2 on -the bridging contact is very high initially, in the order of one hundred pounds, to provide a high acceleration when the current pulse Il is first applied and decreases rapidly as the bridging contact 15 becomes separated from the fixed contacts 13, 14 and the separation distance increases from zero to a few thousandths of an inch. The effect of the permanent magnetic field 30 is shown at 29 to increase the corce exerted on the bridging contact at larger contact separation distances.
Z5~
- 6 - 41PS 6306 A further embodiment of the high speed contact driver 10 of Fig. 1 is shown in Fig. 4 and similar reference nu~bers will be employed where possible. The current loop is provided between conductor 20, bridging contact 15 and conductor 21. A platform 35 of insulating material, supported by a pair of support posts 17, 31 also of insulating material, has an openiny 36 for the passage of the two conductors and serves to support a helix spring 33 which biases the bridging contact against the bias of contact spring 26 in a manner similar to the cantilever spring 18 described earlier with reference to the arrangement depicted in Fig. 1. The platform and the rigid conductors 11, 12 are attached to the support posts 17, 31 by means of screws 19, as indicated.
The conductors 20, 21 are arranged as a single turn secondary winding around a toroidal core 32, with the multi-turn primary winding 34 connected to external circuitry by means of terminal connectors 22, 23 and terminal screws 24, 25. The toroidal core is secured to insulative block 16 and adds to the mass of block 16 for the advantageous relation between this mass and the mass which comprises the bridging contact as described earlier. A current pulse applied to terminal connectors 22, 23 is amplified by transformer action through the core and is induced within the conductors 20, 21 to provide the predetermined current Il which flows in the indicated directions to separate the conductors.
It has thus been shown that extremely fast contact separation can be achieved against a large contact holding force, such as exerted by the contact spring 26 on a small contact mass such as Ml relative to a lesser contact separating force, such as provided by the cantilever spring 18 on a large mass such as M2. When electrodynamic forces are provided to increase the contact separation force, the large mass remains virtually stationary resulting in a large acceleration ` ~2~5254
The conductors 20, 21 are arranged as a single turn secondary winding around a toroidal core 32, with the multi-turn primary winding 34 connected to external circuitry by means of terminal connectors 22, 23 and terminal screws 24, 25. The toroidal core is secured to insulative block 16 and adds to the mass of block 16 for the advantageous relation between this mass and the mass which comprises the bridging contact as described earlier. A current pulse applied to terminal connectors 22, 23 is amplified by transformer action through the core and is induced within the conductors 20, 21 to provide the predetermined current Il which flows in the indicated directions to separate the conductors.
It has thus been shown that extremely fast contact separation can be achieved against a large contact holding force, such as exerted by the contact spring 26 on a small contact mass such as Ml relative to a lesser contact separating force, such as provided by the cantilever spring 18 on a large mass such as M2. When electrodynamic forces are provided to increase the contact separation force, the large mass remains virtually stationary resulting in a large acceleration ` ~2~5254
- 7 - ~lPS 6306 during the initial contact separation which is highly desired for limiting the amount o~ switching current.
It is understood that higher curren-t pulses such as represented by Il can be employed along with stronger magnetic fields to further increase the separation forces and to provide even faster contact separation.
It is understood that higher curren-t pulses such as represented by Il can be employed along with stronger magnetic fields to further increase the separation forces and to provide even faster contact separation.
Claims (11)
1. A high speed contact driver for electric circuit interruption comprising:
a pair of first and second electrical conductors each fixedly attached at one end to an insulated support and arranged side by side, and extending proximate each other;
a bridging contact carried by said electrical conductors at an opposite end thereof to electrically connect said conductors in series, said bridging contact being electrically connected between a pair of fixed contacts; and terminal means for supplying a predetermined current pulse to said conductors at said one end for electrodynamic repulsion of said conductors away from each other to separate said bridging contact from said fixed contacts upon command.
a pair of first and second electrical conductors each fixedly attached at one end to an insulated support and arranged side by side, and extending proximate each other;
a bridging contact carried by said electrical conductors at an opposite end thereof to electrically connect said conductors in series, said bridging contact being electrically connected between a pair of fixed contacts; and terminal means for supplying a predetermined current pulse to said conductors at said one end for electrodynamic repulsion of said conductors away from each other to separate said bridging contact from said fixed contacts upon command.
2. The high speed contact driver of claim 1 wherein said support includes a first spring for providing a tensile force on said conductors and wherein said bridging contact includes a second spring for biasing said bridging contact toward said fixed contacts.
3. The high speed contact driver of claim 1 further including a pair of rigid conductors, supporting said fixed contacts, one of said fixed contacts arranged at one end of each of said rigid conductors.
4. The high speed contact driver of claim 2 wherein said first spring exerts a first force on said bridging contact and said second spring exerts a second force on said bridging contact, said first force being less than said second force.
5. The high speed contact driver of claim 2 wherein said support comprises a first mass and said bridging contact comprises a second mass, said second mass being less than said first mass to promote the rate of separation of said bridging contact from said fixed contacts.
6. The high speed contact driver of claim 2 wherein said first spring is a cantilever spring for moving said conductors and said bridging contact in a first plane of motion.
7. The high speed contact driver of claim 6 wherein said conductors move apart into a second plane of motion perpendicular to said first plane.
8. The high speed contact driver of claim 2 wherein said second spring comprises a helical spring.
9. The high speed contact driver of claim 1 wherein said pair of conductors comprise a first and second wire of predetermined length coextensive with each other.
10. The high speed contact driver of claim 1 wherein said support includes an apertured magnetic core, said pair of electrical conductors being arranged through said aperture on said core.
11. The high speed contact driver of claim 1 further including magnetic means arranged intermediate said ends of said conductors for enhancing said electromagnetic repulsion of said conductors.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000500260A CA1245254A (en) | 1986-01-24 | 1986-01-24 | High speed contact driver for circuit interruption device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000500260A CA1245254A (en) | 1986-01-24 | 1986-01-24 | High speed contact driver for circuit interruption device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1245254A true CA1245254A (en) | 1988-11-22 |
Family
ID=4132331
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000500260A Expired CA1245254A (en) | 1986-01-24 | 1986-01-24 | High speed contact driver for circuit interruption device |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1245254A (en) |
-
1986
- 1986-01-24 CA CA000500260A patent/CA1245254A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |