Abstract:
An electrical protection device is provided. The device can be removably attached to or mounted inside of a power source, such as a vehicle, e.g., automobile, battery and can employ a replaceable fuse element. The device includes an overcurrent protection element, such as a fuse element, and provides any one or more of the following types of electrical protection: (i) overcurrent protection; (ii) accident or catastrophic event power cutout protection; and (iii) load dump protection. The system is configurable to protect certain vehicle electrical components from an overcurrent and allow others to operate independent of the overcurrent protection. Systems and methods employing the protection device are also illustrated and discussed.

Description:
RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. Provisional Application Ser. No. 60/525,196 filed on Nov. 26, 2003 which is incorporated herein by reference. 
     
    
     BACKGROUND  
       [0002]     The disclosed system relates to electrical devices and more particularly to the protection of electrical devices.  
         [0003]     Vehicles, such as cars, trucks, recreational vehicles, motorcycles, truck tractors, motor homes, three-wheeled vehicles, snowmobiles, motorboats, aircraft and others each include electrical devices. Typically, these electrical devices are powered by an on-board battery. Batteries in general store energy in chemical form that is released upon demand as electricity. The electrical power is used by the vehicle&#39;s ignition system for cranking the engine and may power lights and other accessories. Further, should an alternator belt fail, the battery might also need to power the vehicle&#39;s entire electrical system for a short period of time. Automobile batteries are typically twelve volt direct current batteries and supply power over a fairly wide range.  
         [0004]     Automobile batteries are often rated in terms of cold cranking amps, which is the ability of the battery to supply an amount of current for 30 seconds at zero degrees Fahrenheit without dropping below a specified cutoff voltage (this is manufacturer specific and can range from 7.2 volts to 10.5 volts). Cold cranking amps for car batteries can range from about 500 amps to about 1,500 amps. Further, smaller batteries for motorcycles, mopeds and other small vehicles can provide amperages as low as twenty-five amps.  
         [0005]     As more and more complicated electrical systems are placed into automobiles, the need to protect those devices within those systems as well as to protect the automobile battery will increase. There is also significant work being done to develop a 42 volt automobile generator that would drive a 36 volt battery for higher voltage loads. As voltages of batteries increase, the potential damage also increases. It is therefore desirable to provide a device that protects a vehicle&#39;s electrical system when a short circuit or overcurrent condition occurs.  
         [0006]     Another problem associated with vehicle batteries, such as automobile batteries, is load dump. The main battery line in an automobile is the source of a number of potentially harmful transients, including load dump. One form of load dump occurs when the connection from the generator or alternator to the battery is broken. The generator in that time continues to provide power and because the battery is not connected to the generator, the power runs into the voltage regulator causing a voltage rise. The mechanical generator typically needs several hundred milliseconds to bring the overvoltage situation under control, but during that time it is possible for the voltage to rise as high as 200 volts. Another form of load dump occurs when a battery cable is suddenly disconnected from the battery. Such a situation can cause overstresses of electronic parts connected to the battery due to the inertial energy within the vehicle&#39;s electrical system. A need therefore exists to protect vehicle devices connected to the battery from the dangers due to overvoltage caused by load dump.  
         [0007]     Also, as automobiles add electronics to historically mechanical devices, the potential danger upon an accident or other type of catastrophic vehicle event, such as a fire, increases. It is desirable to discontinue power to many electrical components upon such an event. For example, many automobile fuel systems are now controlled electronically. It is desirable to discontinue power to the fuel system upon an accident or catastrophic event to stop the flow of fuel and to minimize injury and damage. Further, an accident can often cause a wire&#39;s conductor to be exposed, wherein the exposed wire can then contact the vehicles chassis and cause a short. The short in turn heats and melts the electrical insulation, potentially causing a fire. A need therefore exists for a device that discontinues power to certain electrical vehicle components. On the other hand, it is desirable to maintain power to other components and functions of the vehicle upon an accident or catastrophic event, such as the automobile&#39;s flashing lights, door locks, cellular telephone, etc. Accordingly, the device should accommodate that need as well.  
       SUMMARY  
       [0008]     A vehicle electrical protection device is provided. The device can be removably attached to a power source, such as the battery of a vehicle. In one embodiment, the protection device is mounted removably to the exterior of the vehicle&#39;s battery. In another embodiment, the protection device is maintained integrally within the battery. In either case, the protection device can have a permanent or replaceable fuse element. That is, in various embodiments, the fuse, the protection device or the power supply employing the device is replaced upon an opening of the fuse element. As described herein, the overcurrent protection device is alternatively resettable.  
         [0009]     For purposes of the present disclosure, the term “vehicle” includes but is not limited to an automobile, a motorcycle, a truck tractor, a motor home, a recreational vehicle, a three-wheeled vehicle, a moped, a motorboat, an aircraft and any combination thereof. Also, the term “power source” includes but is not limited to batteries, fuel cells, solar energy devices and electrical generators. Further, while the terms “fuse” and “fuse element” are used throughout the disclosure, the present invention is expressly not limited to metallic fuse elements and instead includes other types of overcurrent protection devices including resettable overcurrent devices. One such resettable overcurrent devices is a positive temperature coefficient (“PTC”) device.  
         [0010]     The protection device is coupled to the positive and negative terminals of the power source. The device includes a positive contact that is connected electrically to the positive terminal, a negative contact that is connected electrically to the negative terminal and a load contact that is positioned between the positive and negative contacts. In one embodiment, a fuse element is electrically connected between the positive and load contacts. The fuse element is rated for any suitable amperage, such as 20 amps to 2000 amps.  
         [0011]     A switching device is provided and is operable to selectively electrically connect the negative terminal to the load contact. The vehicle&#39;s negative load line is connected electrically to the power source&#39;s negative terminal. The vehicle&#39;s main positive load line (i.e., load line connected to devices which are desirably fuse protected) is connected to the fused load terminal instead of to the power source&#39;s positive terminal. This configuration enables the fuse element to open when: (i) the power draw exceeds the rated amperage; or (ii) when the switching apparatus closes, causing a short between the load/positive terminals and the negative terminal until the fuse element opens.  
         [0012]     The switching apparatus is activated upon an event indicative of an automobile accident or other catastrophe. For example, the switching apparatus can be activated upon the deployment of an airbag. When that occurs, a signal is sent from the airbag, an airbag sensor or an airbag controller to the switching apparatus. The switching apparatus can be one of a multitude of different types of switches. The term “switching apparatus” includes but is not limited to a silicon controlled rectifier (“SCR”), a rotating arm solenoid, a translating arm solenoid, a relay, a metal oxide semiconductor field effect transistor (“MOSFET”) and any combination thereof.  
         [0013]     The switching device is preferably connected to an inductor to reduce the rate of electrical current rise applied to the switch so that the switch closes as designed. The inductor may be formed as a helical metal piece. The inductor may be formed from the same metal piece as the fuse element or from a separate metal piece.  
         [0014]     Each of the electrical load components connected to the fuse protected load line is thus protected from an overcurrent and is de-energized upon an accident or catastrophic event. Certain electrical components within the car may be deemed necessary to be operational upon a catastrophic event or accident (e.g., lights). Therefore, in one embodiment, a second positive load line leading to those non-fuse protected loads is connected to the positive terminal, bypassing the fuse element.  
         [0015]     To combat load dump, an overvoltage or intermediate resistance state device, which allows some of the load dump current to flow through the protection device but not enough to open the element, is connected electrically between the negative contact and the load contact as a voltage limiter. The overvoltage device in essence provides two functions: (i) clamps the voltage at a desired voltage, e.g., fifteen to sixty volts or more; and (ii) limits the amount of current flowing through the device. If a voltage spike from a load dump scenario occurs, e.g., the generator becomes disattached from the battery or a lead becomes disattached from the power source, the overvoltage device clamps any voltage spike occurring along the positive load line and allows the voltage spike to be dissipated across the overall protection device to the negative terminal of the power source and eventually to ground or chassis of the vehicle. The protection device in one embodiment doubles therefore as a load dump protection device.  
         [0016]     To the above described ends, in one embodiment an electrical protection device is provided including: a positive contact configured to be coupled to a positive terminal of a power source; a negative contact configured to be coupled to a negative terminal of the power source, and wherein one of the positive and negative contacts is configured to be placed in electrical communication with a first load line; a load contact configured to be coupled to a second load line; a fuse element connected electrically to one of the positive and negative contacts; and a switching apparatus connected electrically to one of the negative contacts and the load contact.  
         [0017]     The protection device may be mounted inside or outside of the power source. The fuse element may be replaceable. The switching apparatus may be a silicon controlled rectifier (“SCR”), a solenoid, a relay, a metal oxide semiconductor field effect transistor (“MOSFET”), and/or any other suitable switching device. Preferably, the protection device includes a load dump protection device connected electrically to the negative contact and the load contact. The load dump devices discharges a voltage from a load component. The load dump protection device may be a transient voltage suppression (“TVS”) diode, a silicon avalanche diode (“SAD”), a multilayer varistor (“MLV”), a metal oxide varistor (“MOV”), and/or any other suitable load dump protection device.  
         [0018]     Preferably, the switching apparatus is operated by a signal source. The signal source may be from an airbag, an airbag sensor, an airbag controller, a heat sensor, a motion sensor, an impact sensor, a fuel sensor, a pressure sensor, a liquid sensor, and/or any suitable signal source. Example protected load components include a battery cable, a fuel injector, an engine fan, a starter, a heater, a compressor, and/or any other component that should be turned off in case of an emergency. Example non-protected load components include a power locking device (e.g., door), a flashing light, a power window motor, a communications device (e.g., cellular telephone), and/or any other component that should remain on in case of an emergency.  
     
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0019]      FIG. 1  is a perspective view illustrating one embodiment of an automobile electrical system employing an example vehicle electrical protection device.  
         [0020]      FIG. 2  is a perspective view illustrating another embodiment of an automobile electrical system employing an integrally mounted vehicle electrical protection device.  
         [0021]      FIG. 3  is an electrical schematic showing an example vehicle electrical protection device wherein the fuse element and fuse protected contact terminal are placed on a positive side of the battery.  
         [0022]      FIG. 4  is an electrical schematic showing an example vehicle electrical protection device wherein the fuse element and fuse protected contact terminal are placed on a negative side of the battery.  
         [0023]      FIG. 5  is a perspective view illustrating another embodiment of the automobile electrical system employing an example vehicle electrical protection device.  
         [0024]      FIG. 6  is a perspective view illustrating the example vehicle electrical protection device of  FIG. 5 .  
         [0025]      FIG. 7  is a perspective view of the example vehicle electrical protection device of  FIG. 5  showing the helical inductor and fuse assembly.  
         [0026]      FIG. 8  is a front view of the example vehicle electrical protection device of  FIG. 5  showing the helical inductor and the switching apparatus. 
     
    
     DETAILED DESCRIPTION  
       [0027]     Referring now to the drawings and in particular to  FIG. 1 , one embodiment of an electrical protection device used in a vehicle electrical system is illustrated by system  10 . System  10  includes a power source  12 , such as a battery, having a housing  14 . Positive and negative terminals  16   a  and  18   a,  respectively, extend from housing  14 . In the illustrated embodiment, terminals  16   a  and  18   a  extend vertically upward, however, the terminals can extend in any suitable direction from housing  14 . An electrical protection device  20  is fitted onto leads  16   a  and  18   a.  Protection device  20  includes a positive contact  22  that is in electrical communication with positive terminal  16   a  of power source  12 . Protection device  20  also includes a negative terminal  24  that makes electrical contact with negative terminal  18   a.  Device  20  includes a load contact  26  placed between contacts  22  and  24  in the illustrated embodiment.  
         [0028]     Load contact  26  includes or defines a load terminal  28 . Load terminal  28  in one embodiment can have a different and unique shape or size from the shape of terminals  16   a  and  18   a.  As discussed in more detail below, that different shape helps to prevent a misconnection of the load lines.  
         [0029]     A fuse element  30  is provided between contacts  22  and  26 . Fuse element  30  in one embodiment is a curved or straight metal piece having a cross-sectional area less than the area of the contacts  22  to  26 , which creates a weak point in the electrical connection between terminals  16   a  and  18   a,  causing the electrical connection upon an overcurrent to open at fuse element  30 . Contacts  22 ,  24  and  26  can be the same or of a different material or metal as fuse element  30 . Any one or more of those contacts or element can be copper, a copper alloy, zinc or any other suitable metal, such as silver, gold, tin, solder and any combination or alloy thereof. Further, it is possible that any one or more of those contacts or element is plated, e.g., silver plated copper, silver plated zinc, tin plated copper, tin plated zinc or multilayer plating. Fuse element  30  can also be formed from two dissimilar metals. Upon an overcurrent, one metal will diffuse into another to create an alloy with a higher electrical resistance, thereby lowering the temperature required to open the fuse element  30 . Lower temperature metal  32  provides additional control in achieving a fuse element having a desired or defined current rating.  
         [0030]     Giving the term “vehicle” each of its possible meanings described above, fuse element  30  is rated for any suitable vehicle power supply current rating. The amperage rating range is from about 20 amps to about 2,000 amps, but could be configured for higher or lower amperages. A typical automobile application might have an upper current limit of about 50 amps to about 500 amps.  
         [0031]     Protection device  20  in an alternative embodiment includes electrical electrodes  32  shown in phantom, which connect electrically to a replaceable fuse  34  also shown in phantom. Electrodes  32  and replaceable fuse  34  can be used in place of or in addition to fuse element  30 . Indeed, U.S. patent application Ser. No. 10/090,896, entitled Multi-Element Fuse Array, assigned to the assignee of the present invention, the entire contents of which are incorporated by reference, describes a similar type of arrangement. That is, it is possible that fuse element  30  is provided initially, wherein no replacement fuse  34  is needed or used. After fuse element  30  opens, replacement fuse  34  is inserted into electrodes  32  to remake the connection between contacts  22  and contacts  26 . Alternatively, fuse element  30  is not provided and fuse  34  is instead employed initially to make said contact. Further alternatively, electrodes  32  and fuse  34  are not used and device  20  is replaced after element  30  opens.  
         [0032]     Protection device  20 , in an alternative embodiment, is formed on a printed circuit board (“PCB”). In such a case, fuse element  30  includes one or more PCB traces along the board between contacts  22  and  26 , which themselves are copper or other metal provided on the PCB.  
         [0033]     As illustrated, power source  12  and protection device  20  connect removably and electrically to a plurality of load lines. In particular, positive load line  36  is connected to positive terminal  16   a.  Positive load line  38  is connected to load terminal  28 . Negative load line  40  is connected to negative terminal  18   a.  Those physical connections in one embodiment also secure protection device  20  physically in place. Alternatively, protection device  20  is held in place via an independent attachment mechanism (not shown).  
         [0034]     Load line  40  is a negative load line, which extends from negative terminal  18   a  to the vehicle&#39;s chassis or ground. In some instances, such as with a starter that draws a relatively high amount of current, load line  40  extends to the high current component instead of to the chassis. Fuse protected load line  38  extends from load terminal  28  to electrical components within the vehicle that are intended to be protected by fuse element  30 . Bypass load line  36  extends from positive terminal  16   a  to electrical components within the vehicle that are not intended to be protected by fuse element  30 . The terminal heads of load lines  36  and  38  are shaped differently to match differently shaped terminals  16   a  and  28  to at least help to avoid the possibility of connecting electrical components that are not intended to be protected by fuse element  30  to load terminal  28  and vice versa.  
         [0035]     A switching apparatus  50  is provided to selectively make electrical connection between contacts  24  and  26 . In the illustrated embodiment, switching apparatus  50  includes leads  52  and  54 , which can be plug-type leads. In an embodiment, switching apparatus  50  receives via leads  52  and  54  a signal from a vehicle component upon a vehicle collision or catastrophic event. For example, the signal can flow to switching apparatus  50  from an exploded airbag, an airbag sensor, an airbag controller, a heat sensor, a motion sensor, an impact sensor, a force sensor, a fuel sensor, a pressure sensor, a liquid sensor and any combination thereof. That is, multiple different types of sensing devices, alone or in combination, can detect if an accident or other type of harmful situation has occurred and thereafter send a signal to switching apparatus  50 .  
         [0036]     Switching apparatus  50  can be any suitable apparatus that makes electrical contact upon receiving a signal from an external source. For example, the switching apparatus  50  may be a silicon controlled rectifier (SCR), a relay (solid state or mechanical) or a MOSFET. In the illustrated embodiment, switching apparatus  50  is a swing-arm type solenoid that makes contact with a mating member  56  connected electrically to contact  26 . Switching apparatus  50  is shown in a normally open state in  FIG. 1 . Upon receiving a signal from one or more remote accident sensing sources, switching apparatus  50  causes an arm  58  to rotate and make contact with mating member  56 .  FIG. 2  shows an alternative plunger-type switching apparatus  150 , wherein a plunger  158  moves translationally to make contact with mating member  156 .  
         [0037]     In one embodiment, the switching apparatus  50  is a silicon controlled rectifier (“SCR”). The SCR is normally nonconducting as long as an integral gate is at a lower voltage than an integral cathode. If the gate voltage becomes larger than the cathode voltage(e.g., upon receiving a signal from a signal source), the SCR becomes conductive (and may eventually become a short) thereby allowing current to pass from an anode to a cathode. This in turn allows current to flow through electrical protection device  20 , which causes fuse element  30  to open. SCRs are well suited for the present application because (i) SCRs continue to conduct current once they are activated, and (ii) SCRs tend to fail in a conductive mode (i.e., fail short as opposed to fail open).  
         [0038]     However, SCRs and other switching devices  50  intended to close upon an activation signal (e.g., application of an electrical current) may fail open upon excessive current and/or voltage. For example, an SCR may mechanically fail if the SCR experiences a large current spike. Preferably, an inductor  31  is connected in series with the switch  50  to prevent this from happening. The inductor  31  slows the rate of electrical current rise applied to the switch  50  so that the switch closes as designed. In one embodiment, at least one of the two sides the switching device  50  is mechanically biased toward the other side of the switching device  50  in order to keep the two sides of the switching device  50  in electrical contact when the switching device is closed.  
         [0039]     In one embodiment, the switching apparatus  50  is a MOSFET. MOSFETs employ a breakdown voltage, which is the voltage at which a reverse biased diode breaks down to enable significant current to flow between a source and a drain. In system  10 , the MOSFET breaks down at a particular voltage supplied by the signal source to enable current to flow directly between terminals  16   a  and  18   a,  causing fuse element  30  to open.  
         [0040]     As discussed above, it is desirable to discontinue power to a vehicle&#39;s electrical system upon an accident or catastrophic event. For example, vehicle components that may need to be protected upon such event include, but are not limited to, a battery cable, a fuel injector, an engine fan, a starter, a heater, a compressor and any other component, especially high current draw components. On the other hand, components that may need to continue to receive power after an accident or catastrophic event may include, but are not limited to, a power locking device (e.g., door), headlights, interior lights, emergency lights, automatic window motors, communications systems (e.g., cellular telephone, On-Star™, etc.) and potentially others. Protection device  20  enables such a fuse/bypass configuration.  
         [0041]     Some batteries provide top mount terminals as shown as terminals  16   a  and  18   a  Other batteries provide side mount terminals as shown in phantom as terminals  16   b  and  18   b.  Either type of terminal may be used with the protection device  20  described herein.  
         [0042]     As illustrated and discussed, fuse element  30  opens in a first instance when too much current is being demanded from fuse protected load line  38 . In that manner, fuse element  30  provides overcurrent protection to the components connected to line  38 . Fuse element  30  also protects the power source from being overly stressed. Fuse  30  in a second instance also opens upon a vehicle accident or catastrophic event when switching apparatus  50  receives a signal indicating such event and closes to make a direct connection between terminals  16   a  and  18   a.  It should be appreciated that device  20  in alternative embodiments is provided having only overcurrent protection or only disaster or catastrophic event protection.  
         [0043]     Further alternatively, any combination of the above types of protection can be combined with a third type of protection provided by protection device  20 , namely, load dump protection. As discussed above, vehicle load dump can be caused via a number of electrical connection failures within the vehicle, such as a failed connection between the vehicle&#39;s generator and battery or a disconnection of one of the leads, e.g., leads  36 ,  38  or  40  from its respective terminal, namely, terminals  16   a,    28  and  18   a.  A load dump can cause a rather high voltage spike or transient to occur within the vehicle&#39;s electrical system.  
         [0044]     To combat load dump, an overvoltage protection device  60  is connected electrically to contact  24  and contact  26 . Overvoltage protection device  60  clamps the voltage spike cause by load dump and enables an intermediate amount of current, e.g., an amount less than the fuse element rating, to flow though electrical protection device  20  to negative terminal  18   a,  negative load line  40  and eventually to the vehicle chassis or other type of vehicle or non-vehicle ground. Overvoltage device  60  can be but is not limited to a transient voltage suppression (“TVS”) diode, a silicon avalanche diode (“SAD”), a multilayer varistor (“MLV”) and a metal oxide varistor (“MOV”), each of which exhibit and are selected to have a particular clamping voltage.  
         [0045]     Overvoltage device  60  is sized or selected to have a voltage above the normal operating range of: (i) the power source or (ii) the electrical system, e.g., above 12 volts or 14 volts for an automobile battery and electrical system respectively, but lower than a voltage that could potentially cause harm to components within the vehicle. One suitable range of clamping voltages for overvoltage protection device  60  is from about fifteen volts to about sixty volts. The present invention is expressly not limited to such range especially in light of the current work being done to develop 36 volt battery and 42 volt automobile generation systems. Further, non-vehicle type power generation systems could require lower or higher and potentially significantly higher clamping voltages.  
         [0046]     In normal operation, e.g., when no load dump condition is present, overvoltage protection device  60  has a high resistivity. The normal resistance of overvoltage protection device  60  is such that very little current flows across protection device  20 . When a voltage transient or spike does occur, overvoltage protection device  60  switches to a controlled and intermediate resistivity and clamps the spike at a suitable voltage, which enables the energy from the spike to dissipate across protection device  20  to the vehicle chassis or otherwise to ground.  
         [0047]     As discussed above, electrical protection device  20  can include any combination of the different types of electrical protection described herein, including only providing load dump protection if desired. Protection device  20  is capable, however, of providing overcurrent protection, catastrophic event or accident protection as well as load dump protection.  
         [0048]      FIG. 1 . illustrates a number of embodiments for replacing or resetting protection device  20  after the fuse element  30  opens, including completely replacing protection device  20  or replacing an opened replaceable fuse  34 , such as a blade fuse.  FIG. 2  illustrates an alternative system  110 , wherein an alternative device  120  is integrated within an alternative power source  112 . Alternative device  120  includes many of the same components described above and numbered the same, such as contacts  22 ,  24  and  26 . Those contacts are shown in phantom because they are installed beneath the housing  114  of power source  112 . Each of the components shown in solid resides on top of power source  112 .  
         [0049]     As discussed above, a fuse element  30  is electrically connected between contacts  22  and  26 . An alternative switching device  150  is positioned to make electrical contact with mating member  156 . Mating member  156  then connects to contact  26  via inductor  31 . Placed in parallel with switching apparatus  150  is an overvoltage protection device  60  that provides load dump protection as described above. The power source also includes terminals  16   a  and  18   a  as described above and can include alternative side extending terminals  16   b  and  18   b  described in connection with  FIG. 1 .  
         [0050]     Terminals  16   a  and  18   a  are connected electrically to device contacts  22  and  24 , respectively, via internal leads  116  and  118 , respectively. The load terminal  28  is also provided on top of power source  112  and makes an electrical connection with contact  26  via lead  128 . As before, load terminal  28  can have a different shape than positive terminal  16   a  to prevent improper electrical connection. The same load lines  36  to  40  described above can be used in connection with system  110  of  FIG. 2 . Protection device  120  also includes electrical electrodes  132  that receive a replacement fuse  34  if initial fuse element  30  is opened. Alternatively, fuse element  30  is not provided and instead the fuse or blade fuse  34  is used initially. Further alternatively, electrodes  132  and fuse  34  are not used, wherein power source  112  is discarded after fuse element  30  is opened.  
         [0051]     A suitable viewing window  122  is provided so that the vehicle operator or technician can detect that fuse element  30  has opened. It is also possible to coat fuse element  30  with a suitable material that vaporizes with heat and collects on viewing window  122  to provide further visual evidence that fuse element  30  has opened.  
         [0052]     In a similar manner, a connector  160 , such as a plug connector, is provided and placed in electrical contact with signal leads  152  and  154  of switching apparatus  150 . The operator simply connects a mating signal line connector (not illustrated) into connector  160  to enable operation of switching apparatus  150 . Device  120  operates the same as and includes all the same operational alternatives as described above for device  20 .  
         [0053]     Referring now to  FIGS. 3 and 4 , various electrical configurations for the protection devices of the present invention are illustrated. For purposes of illustration, power source  12  and the components used in connection with system  10  and device  20  in  FIG. 1  are shown. It should be appreciated, however, that each of the alternatives shown in  FIGS. 3 and 4  is equally applicable to system  110  and protection device  120  of  FIG. 2 .  
         [0054]     Each of  FIGS. 3 and 4  includes a schematically representative positive contact  22 , negative contact  24  and load contact  26 . In addition, each of the configurations includes a switching apparatus  50  shown figuratively as a relay. Each configuration also includes the overvoltage protection device  60  operating in parallel with switching apparatus  50  described above. Further, each of the configurations includes a fuse element  30  and an inductor  31 .  
         [0055]     The configurations also include a fuse element protected load  66  and an unprotected or bypass load  68 . Those loads refer respectively to electrical components within the vehicle that are either desirably fuse protected or left powered upon a vehicle accident or catastrophic event. The configurations differ primarily in the placement of the fuse element  30  and the contact terminal  26 . The configurations each operate exactly the same, however, they illustrate that the present invention includes any configuration that achieves the stated functions of the device  20 .  
         [0056]      FIG. 3  illustrates schematically the arrangement of components shown in  FIG. 1 .  FIG. 4  moves fuse element  30 , inductor  31 , and contact  26  to the negative side of load  66 , so that both are positioned on the opposite side of load  66  from positive contact  22 , and so that both are in direct electrical communication with negative contact  24 .  
         [0057]      FIGS. 5-8  illustrate another example of the protection device  20 . In  FIG. 5 , the protection device  20  is mechanically connected to the side terminals  16   b  and  18   b  of a power source  12 , such as an automobile battery. As shown in the example configuration of  FIGS. 5-8 , the protection device  20  includes a fuse element  30  and an inductor  31 . In this example, the fuse element  30  is a straight metal piece having a reduced cross-sectional area, which creates a weak point in the electrical connection. When an overcurrent condition occurs, the fuse element  30  permanently opens.  
         [0058]     In this example, the inductor  31  is formed as a helical metal piece. The inductor  31  may be formed from the same metal piece as the fuse element  30  or from a separate metal piece. Any suitable material may be used to form the inductor  31 . In addition, the inductor  31  may be of any suitable shape. For example, a square or rectangular shaped inductor may be used. The inductor  31  may be constructed to electrically connect two pieces in two separate planes (as shown), or the inductor  31  may be constructed substantially in a single plane. In one embodiment, the inductor  31 , or a portion of the inductor  31 , also acts as the fuse element  30 .  
         [0059]     As shown in  FIG. 8 , the protection device  20  also includes a switching apparatus  50 . In this example, the switching apparatus  50  is an SCR device. The helical inductor  31  slows the rate of electrical current rise applied to the SCR so that the SCR “melts” together to form a permanently closed connection.  
         [0060]     It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present invention and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.