Patent Application
20140091061
The present application relates generally to electrical current contact arc suppression.
Electrical current contact arcing may have a deleterious effects on electrical contact surfaces, such as of relays and certain switches. Arcing may degrade and ultimately destroy the contact surface over time and may result in premature component failure, lower quality performance, and relatively frequent preventative maintenance needs. Additionally, arcing in relays, switches, and the like may result in the generation of electromagnetic interference (EMI) emissions. Electrical current contact arcing may occur both in alternating current (AC) power and in direct current (DC) power across the fields of consumer, commercial, industrial, automotive, and military applications. Because of its prevalence, there have literally been hundreds of specific means developed to address the issue of electrical current contact arcing.
Some embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings.
Arc suppression devices that have been developed in the art may be categorized according to three broad categories. Such categories may include: the use of devices, the design of contacts, and the use of discrete components.
With respect to the use of devices, various hybrid power switching devices have been developed to address the effects of contact current arc suppression. These devices typically rely on a coil or other input information to infer the presence of an arc. The use of an input triggered by the coil activation of a relay may be problematic, as the timing of coil activation and contact separation may vary over the operating life of the relay. The use of an optical arc detection input may be problematic, as the arc may occur so fast that the arc may be completed before an optical signal may be both read and acted upon.
With respect to contact design, various types of contact design have also been employed to combat the effects of contact current arc suppression. Relatively larger contact surfaces, such as may be typical of contactors, and/or contacts made of relatively more durable metals may simply take longer for arcing to destroy than may be the case with conventional contacts. Contacts have been used in a gap environment, such as a vacuum or a liquid or gas environment, that suppresses the arc. Magnets have been utilized to magnetically suppress arcs by mitigating or “blowing out” the arc after the arc has formed.
With respect to discrete components, current limiters, voltage limiters and risetime limiters have been utilized to attempt to address the effects of contact current arc suppression. RC snubbers, for example, are a series combination of a resistor and a capacitor in order to provide EMI suppression and voltage risetime (dV/dt) reduction. Snubbers may limit some EMI from an arc; however, snubbers may be of reduced or minimal effectiveness in actually suppressing an arc. Voltage suppressors, such as a metal oxide varistor (MOV), a transient voltage suppressor (TVS) diode, and Zener diodes have also been utilized. Voltage suppressors may address the over-voltages created by an inductive load during certain stages of contact separation, but may not actually suppress the arc.
Such previous efforts at arc suppression may lessen an effect of an arc without fundamentally or significantly reducing the arc itself. While snubbers may be commonly utilized to reduce the EMI effect of an arc, snubbers may have little impact on protecting the contacts against the physical effects of the arc. Similarly, while contacts may be reinforced to improve their resistance to the effects of arcing, reinforcement may merely delay the physical impact of an arc while also failing to reduce other effects and, at the same time, increase the size and cost of the contact.
An arc suppressor has been developed that may interrupt, at least in part, undesirable contact arcing and potentially protect, at least in part, a contact from deleterious effects. The arc suppressor may utilize a processor (the processor being any of a variety of suitable electronic components, as disclosed herein) to control the connection of a bypass across the contacts. A contact separation detector may detect a condition indicative of a separation of the contacts, such as a change in voltage and/or current, as disclosed herein, and output an indication of the contact separation. The indication may be output directly to the bypass, in which case a processor may not necessarily be utilized, or to the processor, which may connect the bypass over the contacts. Connecting the bypass over the contacts may thereby reduce the energy over the contacts until the conditions over or between the contacts that may cause or lead to an arc have passed. As such, the arc may not form in the first instance or may not form past an initial, non-damaging level or “arclet”, as disclosed herein. The arc suppressor may significantly reduce electromagnetic emissions resulting from contact arcing in contrast to alternative methodologies, in various examples owing to the arc having been extinguished or substantially reduced. The arc suppressor may be relatively scalable to cover a range of applications from low power to high power, from small size to large size, and from simple to complex.
In various examples, the arc suppressor may monitor and indicate the status of a contact. While the arc suppressor disclosed herein will be discussed in particular with respect to electrical contacts, it is to be recognized and understood that the arc suppressor may be applicable with respect to other electrical members between which an arc may form, such as fixed electrodes and the like. In various examples, the arc suppressor may detect electrical changes related, at least in part, to the contact, such as contact voltage and current through an RC circuit coupled over the contact. In various examples, the arc suppressor does not have a significant power-on current pass through. The arc suppressor may reduce overstress on a capacitor in the RC circuit relative to other arc suppression technologies. In various examples, the arc suppressor does not generate more current leakage than an RC snubber known in the art.
In various examples, the arc suppressor does not singly rely on current change detection or voltage change detection for bypass element triggering. Rather, the arc suppressor may utilize or rely upon both current change detection and voltage change detection. In various examples, the arc suppressor may reduce, eliminate, or substantially eliminate spurious oscillation.
In various examples, the arc suppressor may permit contacts to be constructed relatively smaller and of relatively less exotic material than contacts of alternative arc suppression technologies, owing, for instance, to the reduced potential for damage to the contacts from arcing over alternative arc suppression technologies. Additionally, in various examples, the arc suppressor may allow contacts to operate at a faster rate, at higher ambient temperatures, and at higher duty cycles than contemporary contacts designed to operate with alternative arc suppression technologies. In various examples, the arc suppressor may be connectorizable and contact agnostic, contactor agnostic, hook-up agnostic, load agnostic, polarity agnostic, power agnostic, and device agnostic (that is to say, the arc suppressor works on switch contacts, relay contacts, and/or contactor contacts).
In various examples, the arc suppressor may be implementable in semiconductor technology and be micro-miniaturizable. In various examples, the arc suppressor may be integrated into a conventional relay case or within the case of other electronic circuits or devices. In various examples, the arc suppressor may be applied to the regulation of electronic circuitry in ways that are not necessarily limited to arc suppression circumstances, such as in the detection of an arc without necessarily intending to suppress the arc. In various examples, the arc suppressor switchably or alternatively operates on DC and on AC power, and, in various examples, on DC and AC power concurrently. In various examples, the arc suppressor operates on DC or AC power. In various examples, the arc suppressor operates on external power. In various examples, the arc suppressor operates on internal power.
The arc suppressor may extend, at least in part, the life of contacts used in switches, relays, and contactors, among other potential circuits or components, used to switch either an alternating current (AC) and/or a direct current (DC) source to a load. The arc suppressor can, in various examples, suppress arcing, suppress electromagnetic interference, suppress of the creation of fine particles, suppress deleterious effects to the contact, extend contact life, and improve contact performance.
The system 100 includes a power source 104, a contact 106, and a load 108. The power source 104 may be an AC power source or a DC power source. Sources for AC power may include generators, alternators, transformers, and the like. The source for AC power may be sinusoidal, non-sinusoidal, or phase controlled. An AC power source may be utilized on a power grid (e.g., utility power, power stations, transmission lines, etc.) as well as off the grid, such as for rail power. Sources for DC power may include various types of power storage, such as batteries, solar cells, fuel cells, capacitor banks and thermopiles, dynamos, and power supplies. DC power types may include direct, pulsating, variable, and alternating (which may include superimposed AC, full wave rectification and half wave rectification). DC power may be associated with self-propelled applications, i.e., articles that drive, fly, swim, crawl, dive, tunnel, dig, cut, etc.
The contact 106 may be a switch, relay, contactor, or other contact. The contact 106 includes a pair of contacts, such as electrodes, as illustrated herein. As noted above, the contact 106 may alternative be a static electrode or electrodes or other component over which an arc may tend to form. The load 108 may be a general purpose loads, such as consumer lighting, computers, data transfer switches, etc. The load 108 may be a resistive load, such as a resistor, heater, electroplating device, etc. The load 108 may be a capacitive load, such as a capacitor, capacitor bank, power supply, etc. The load 108 may be an inductive load, such as an inductor, transformer, solenoid, etc. The load 108 may be a motor load, such as a motor, compressor, fan, etc. The load 108 may be a tungsten load, such as a tungsten lamp, infrared heater, industrial light, etc. The load 108 may be a ballast load, such as a fluorescent light, neon light, light emitting diode (LED), etc. The load 108 may be a pilot duty load, such as a traffic light, signal beacon, control circuit, etc.
In the illustrated example, connection between the power source 104 and the contact 106 is via a non-switched contact current node 110. Connection between the contact 106 and the arc suppressor 102 is optionally via a wire connection 112 affixed to a wire terminal 114 of the arc suppressor 102. Connection between the contact 106 and the load 108 is optionally via a switched contact current node 116. A second connection between the contact 106 and the arc suppressor 102 is optionally via a wire connection 118 affixed to a wire terminal 120 of the arc suppressor 102. Connection between the load 108 and the power source 104 is optionally via a return wire connection 122. Thus, the arc suppressor 102 is connected directly in parallel with the contact 106 to be protected.
The arc suppressor 102 may optionally be coupled to an external power supply via a power supply connection 124. The arc suppressor 102 may further optionally be coupled to an external status monitor via a status monitor connection 126. It is emphasized that, as with various components of the system 100, while the power supply connection 124 and status monitor connection 126 are illustrated, such components are optional and may not be included in various examples of the system 100.
The block diagram of the arc suppressor system 198 includes elements of the arc suppressor system 198 generically and without respect to specific voltage, current or power ratings. In various specific implementations, the various blocks may be scaled according to component ratings such as, but not limited to, resistance, capacitance, inductance, voltage, current, power, tolerance, and transformation ratio, to construct specific arc suppressors.
The contact separation detector 200 may detect a condition indicative of a separation of the contact 106, such as a change in voltage and/or current, as disclosed herein. The condition indicative of the separation of the contacts 106 may more generally be a condition indicative of an arc or a formation of an arc, and circumstances in which the contact separation detector 200 is utilized without respect to contacts may produce a detection and an indication of an arc or a condition indicative of an arc. The contact separation detector 200 may, in various examples, output an analog signal that, at relatively low values, indicates a condition, such as a contact separation state, that may not necessarily result in the bypass of the contacts 106. The contact separation detector 200 may, in various examples, output an analog signal that, at relatively higher values, indicates the formation of an arc, as disclosed herein, that may result in bypassing the contacts 106. The values of those indications may be dependent on the circumstances in which the contact separation detector 200 is applied and may be utilized by one or more of the indicator 202, processor 204, and bypass 206 to variously indicate the separations state of the contact 106, indicate an arc condition over the contact 106, and/or bypass the contact 106, as appropriate.
The contact separation detector 200 may output an indication of the contact separation. As illustrated, the indicator is provided to the processor 204. However, in various examples, the indicator may be provided, alternatively or additionally, to the indicator 202 and/or to the contact bypass circuit 206 without respect to the processor 204. On the basis of receiving the indication, the processor 204 may output a trigger signal to engage the electrical bypass of the contact bypass circuit 206 over the contact 106. Alternatively, the contact bypass circuit 206 may receive the indication directly from the contact separation detector 200 and engage the bypass over the contact 106. By bypassing the contact 106 during at least a portion of the time during which the arc may form or tend to form over the contact 106, the energy over the contact 106 may be reduced to levels that may not produce an arc until the conditions within the contact 106 that may cause an arc have passed or otherwise subsided.
The component protection circuit 208 and the protection circuit 210 may provide protection for the various components within the arc suppressor system 198. In various examples, the component protection circuit 208 includes one or more of a varistor, a transient voltage suppressor, and back-to-back Zener diodes coupled in parallel with one or more of the contact separation detector 200, the processor 204, and the contact bypass circuit 206. In various examples, the protection circuit 210 includes one or more of a fuse, a resistor, a circuit breaker, and a fusible link coupled in series with one or more of the contact separation detector 200, the processor 204, the contact bypass circuit 206, and the component protection circuit 208.
The connection termination 212 may be a component of the contact 106 itself and may, in various examples, not be considered a component of the arc suppressor system 198. In various alternative examples, the arc suppressor system 198 may be considered an integral component of the contact 106. The contact termination 212 may be one or more of wire terminals, a pluggable connector, a card-edge connector, and flying leads. The power connection 214 and power supply 216 may optionally supply power to the arc suppressor system 198 as a whole, such as to the processor 204. The power connection 214 may be any one or more of wire terminals, a pluggable connector, a card-edge connector, flying leads, and a power connector. The power supply 216 may be any one or more of a battery, a capacitor, one or more voltage regulators, and one or more power regulators.
The arc suppressor system 198 may be implemented according to any of a variety of embodiments of some or all of the blocks 200, 202, 204, 206, 208, 210, 212, 214, 216. While specific embodiments are presented in detail herein, it is to be understood that alternative embodiments may be implemented. The particular embodiments may be configured to provide desired performance characteristics, such as for the circumstances in which the arc suppressor system 198 is used. The particular embodiments disclosed herein are for the purposes of example and illustration and are not limiting on the implementations disclosed herein.
The arc suppressor system 198 may be configured for any of a variety of applications and circumstances. In various examples, the arc suppressor system 198 supports electric vehicle automobile battery voltages, such as an automobile battery voltage of approximately one thousand (1000) Volts DC. In various examples, the arc suppressor supports hybrid electric automobile battery voltages, such as a hybrid electric automobile battery voltage of approximately five hundred (500) Volts DC. In various examples, the arc suppressor supports various sizes and power capabilities to support a change from a current automobile vehicle standard battery voltage, such as a voltage of twelve (12) Volts DC, to a new automotive vehicle standard battery voltage, such as approximately forty-two (42) Volts DC. In various examples, the arc suppressor supports various sizes and power capabilities to support the electric vehicle automobile battery voltages, such as electric vehicle automobile battery voltages of up to and in excess of approximately one thousand (1000) Volts DC. In various examples, the arc suppressor supports various sizes and power capabilities to support hybrid electric automobile battery voltages, such as hybrid electric automobile battery voltages of up to approximately five hundred (500) Volts DC.
In various examples, the arc suppressor 300 includes the following components: a first capacitor 320 having a capacitance of 0.1 microFarads; a first resistor 322 having a resistance of one hundred (100) Ohms; a Hall-effect sensor 324; a transmission line driver 326; a system on a chip 328, such as may operate at twenty-four (24) megahertz; a field effect transistor 330 configured to be coupled across a fifteen (15) Volt supply; a second resistor 332 of fifteen (15) kiloOhms; a third resistor 334 of thirty-three kiloOhms; first, second, and third IGBTs 336, 338, 340 having a collector-emitter breakdown voltage of one thousand seven hundred (1700) Volts, a current collector of two hundred (200) Amperes, and a maximum power of one thousand forty (1040) Watts; a bridge rectifier 342; a varistor 344 rated up to one thousand (1000) Volts; and a fuse 346 of up to thirty (30) Amperes and one thousand (1000) Volts. A case 348 may enclose the system 300. In the illustrated example and with the component values listed, the arc suppressor 300 may support a one (1) megaWatt contact 106 and applications of one thousand (1000) Volts DC across the contact 106 and one thousand (1000) Amperes through the contact 106. A
The above example is non-limiting, and arc suppressor systems may be developed according to the principles and topologies disclosed herein to meet specifications across a range of applications. Arc suppressors as disclosed herein may be fabricated using a variety of technologies known in the art, including solid state, ceramic, and thick film technologies. A family of arc suppressor devices may be scaled from small size to large size, low power to high power, low voltage to high voltage, low current to high current.
It is to be understood that the arc suppressor examples disclosed herein may be carried out by different equipment and devices, and that various modifications, both as to the equipment and operating procedures, may be accomplished without departing from the scope of the arc suppressor itself.
The description of the various embodiments is merely exemplary in nature and, thus, variations that do not depart from the gist of the examples and detailed description herein are intended to be within the scope of the present disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the present disclosure.
At 400, an electrical contact is coupled to a contact separation detector of an arc suppressor, the electrical contact including a pair of contacts configured to couple a power source to a load, the contact separation detector configured to output an indication of a separation state of the pair of electrical contacts. In an example, the electrical contact is an electrode.
At 402, a contact bypass circuit of the arc suppressor is coupled to the contact separation detector, wherein the contact bypass circuit is configured to provide an electrical bypass between the pair of contacts based on the indication as provided by the contact separation detector.
At 404, the electrical contact and the arc suppressor are enclosed in a case. In an example, the electrical contact is a relay and wherein the case is a relay case.
At 406, the power source and the load are coupled to the electrical contact. In an example, the power source is an automotive battery and wherein the arc suppressor is configured to prevent arcing over the pair of contacts at an automotive battery voltage. In an example, the load comprises an electric drivetrain.
At 408, a return connection is coupled between the power source and the load.
At 410, a switch is coupled to the arc suppressor, wherein the electrical contact is a component of the switch.
At 412, a connector is coupled to the arc suppressor, wherein the electrical contact is a component of the connector.
The description of the various embodiments is merely exemplary in nature and, thus, variations that do not depart from the gist of the examples and detailed description herein are intended to be within the scope of the present disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the present disclosure.
In Example 1, a system includes an electrical contact including a pair of contacts configured to couple a power source to a load and an arc suppressor, coupled to the electrical contact. The arc suppressor includes a contact separation detector configured to output an indication of a separation state of the pair of electrical contacts and a contact bypass circuit, coupled to the contact separation detector, configured to provide an electrical bypass between the pair of contacts based on the indication as provided by the contact separation detector.
In Example 2, the system of Example 1 optionally further includes a case configured to enclose the electrical contact and the arc suppressor.
In Example 3, the system of any one or more of Examples 1 and 2 optionally further includes that the electrical contact is a relay and wherein the case is a relay case.
In Example 4, the system of any one or more of Examples 1-3 optionally further includes the power source and the load.
In Example 5, the system of any one or more of Examples 1-4 optionally further includes that the power source is an automotive battery and wherein the arc suppressor is configured to prevent arcing over the pair of contacts at an automotive battery voltage.
In Example 6, the system of any one or more of Examples 1-5 optionally further includes that the load comprises an electric drivetrain.
In Example 7, the system of any one or more of Examples 1-6 optionally further includes a return connection between the power source and the load.
In Example 8, the system of any one or more of Examples 1-7 optionally further includes a switch, wherein the electrical contact is a component of the switch.
In Example 9, the system of any one or more of Examples 1-8 optionally further includes a connector, wherein the electrical contact is a component of the connector.
In Example 10, the system of any one or more of Examples 1-9 optionally further includes that the electrical contact is an electrode.
In Example 11, a method includes coupling an electrical contact to a contact separation detector of an arc suppressor, the electrical contact including a pair of contacts configured to couple a power source to a load, the contact separation detector configured to output an indication of a separation state of the pair of electrical contacts and coupling a contact bypass circuit of the arc suppressor to the contact separation detector, wherein the contact bypass circuit is configured to provide an electrical bypass between the pair of contacts based on the indication as provided by the contact separation detector.
In Example 12, the method of Example 11 optionally further includes enclosing the electrical contact and the arc suppressor in a case.
In Example 13, the method of any one or more of Examples 11 and 12 optionally further includes that the electrical contact is a relay and wherein the case is a relay case.
In Example 14, the method of any one or more of Examples 11-13 optionally further includes coupling the power source and the load to the electrical contact.
In Example 15, the method of any one or more of Examples 11-14 optionally further includes that the power source is an automotive battery and wherein the arc suppressor is configured to prevent arcing over the pair of contacts at an automotive battery voltage.
In Example 16, the method of any one or more of Examples 11-15 optionally further includes that the load comprises an electric drivetrain.
In Example 17, the method of any one or more of Examples 11-16 optionally further includes coupling a return connection between the power source and the load.
In Example 18, the method of any one or more of Examples 11-17 optionally further includes coupling a switch to the arc suppressor, wherein the electrical contact is a component of the switch.
In Example 19, the method of any one or more of Examples 11-18 optionally further includes coupling a connector to the arc suppressor, wherein the electrical contact is a component of the connector.
In Example 20, the method of any one or more of Examples 11-19 optionally further includes that the electrical contact is an electrode.
The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments. These embodiments are also referred to herein as “examples.” Such examples may include elements in addition to those shown and described. However, the present inventor also contemplates examples in which only those elements shown and described are provided.
All publications, patents, and patent documents referred to in this document are incorporated by reference herein in their entirety, as though individually incorporated by reference. In the event of inconsistent usages between this document and those documents so incorporated by reference, the usage in the incorporated reference(s) should be considered supplementary to that of this document; for irreconcilable inconsistencies, the usage in this document controls.
In this document, the terms “a” or “an” are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” In this document, the term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended, that is, a system, device, article, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.
The above description is intended to be, and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments may be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to comply with 37 C.F.R. §1.72(b), to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.
This application claims priority under 35 U.S.C. 119(e) to U.S. Provisional Application No. 61/707,373, “ARC SUPPRESSOR,” filed Sep. 28, 2012, which is incorporated herein in its entirety. This application claims priority under 35 U.S.C. 119(e) to U.S. Provisional Application No. 61/788,786, “ARC SUPPRESSOR,” filed Mar. 15, 2013, which is incorporated herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61707373 | Sep 2012 | US | |
| 61788786 | Mar 2013 | US |
