MXPA95003931A - Double breaking circuit circuit breaker higher secondary - Google Patents

Abstract

The present invention relates to a circuit breaker for passing current during a normal condition and, in response to at least one abnormal condition, interrupting the current, comprising: a pair of primary contact sets, each of the contact assemblies primary including a respective contact, at least one of the primary contact sets being constructed and arranged to interrupt the current moving from a normally closed position to an open position, a linking member that provides a bonding force in response to the movement of one of the sets of primary contacts from the normally closed position, one spring, and a pair of sets of secondary contacts, each of the sets of secondary contacts including a respective contact, one of the secondary sets being stationary and the other of the sets of secondary contacts having a movable contact arm coupled to the linking member and capable of rotating about a pivot and biased by the spring to a normally closed position such that, in response to an overcurrent condition exceeding a predetermined level, the movable contact arm rotates away from the position normally closed until the overcurrent condition falls below the predetermined level, at which time the movable contact arm rotates to the normally closed position and, in response to the bonding force provided by the linking member, the arm Movable contact of said other set of secondary contacts rotates away from the position normally closed

Description

DOUBLE BREAKING CIRCUIT CIRCUIT BREAKER HAVING IMPROVED SECONDARY SECTION Field of the Invention The present invention relates generally to circuit breakers and, more particularly, to circuit breakers having multiple sets of contacts to interrupt a single current path through the circuit breaker. BACKGROUND OF THE INVENTION The use of circuit breakers in current residential, commercial and industrial electrical systems is widespread and is an indispensable component of such systems to provide protection against overcurrent conditions. Various circuit breaker mechanisms have been developed and refined over time based on specific application factors such as current capacity, response time, and the type of reset function (manual or remote) desired of the circuit breaker. One type of circuit breaker mechanism employs a thermo-magnetic trip device to "trip" a latch in response to a specific range of overcurrent conditions. The triggering action is caused by a significant deflection in a bi-metal or thermostat-metal element that responds to changes in temperature due to resistance heating caused by the flow of electrical current from the circuit through the element. The metal thermostat element is typically in the form of a flat metal member and operates in conjunction with a latch so that the deflection of the metal member releases the latch after a time delay corresponding to an overcurrent threshold. predetermined in order to "break" the associated current circuit. Circuit circuit breakers of this type often include an electro-magnet that operates on a lever to release the circuit breaker latch in the presence of a very high short-circuit or current condition. A handle or button mechanism is also provided to open the electrical contacts to the required separation width and sufficiently fast to perform an adequate interruption of the current. Another type of circuit breaker, referred to as a "double break" circuit breaker, includes two sets ", of current breaking contacts to accommodate a higher level of overcurrent conditions than that accommodated by the above-discussed one such double-circuit circuit breaker implements its two sets of contacts using the respective ends of a elongated blade, capable of rotating as movable contacts that are attached to the non-movable contacts disposed adjacent to the non-movable contacts.The non-movable contacts are located at the ends of respective r-stationary U-shaped terminals, so that a Explosive electromagnetic force arises when the current, which exceeds the threshold level, passes through the U-shaped terminals. In this way, when this high-level overcurrent condition is present, the explosive force causes the blade elongated able to rotate turn and the two sets of contacts separate simultaneously.Other type of double break circuit circuit breaker implements its s two sets of contacts using separate and independent structures. For example, a set of contacts can be implemented using the thermomagnetic trip device previously discussed to trigger the current path at low-level current conditions, and the other set of contacts using an intricate and current-sensitive array that separates its contacts. contacts in response to high level explosive current conditions. See, for example, U.S. Patent Nos. 3,944,953; 3,946,346; 3,943,316 and 3,943,472, each of which was assigned to the same assignee as the present one. Although they provide adequate protection to high level overcurrent conditions, such double-circuit circuit breakers are too complex and difficult to manufacture and service. With respect to its manufacture, for example, the complexity of the control mechanism for separating each set of contacts is added in a significant way to the global account of component parts for the circuit breaker. As a result, the materials and assembly costs for such circuit breakers are relatively high. The double-break circuit breakers also have disadvantages of energy loss that are not found in the circuit breaker (single break) described in the foreground. These double-break circuit breakers typically develop contact resistances that create higher energy losses. Energy losses fluctuate "* from one operation to the next, thereby making the double-circuit circuit breaker unreliable and cumbersome to conserve, and there is a need for a double-break circuit breaker that can be implemented without The aforementioned disadvantages SUMMARY OF THE INVENTION The present invention provides a circuit breaker having a double breakthrough current path switching mechanism that overcomes the aforementioned deficiencies of the prior art.The present invention further provides a circuit breaker which it has a double-burst current path switch mechanism that operates with lower peak currents, lower I2t power, and high rated interrupt ratings in a relatively small package.

In an implementation of the present invention, a circuit breaker includes a pair of primary contact sets, a spring and a pair of secondary contact sets. At least one of the sets of primary contacts interrupts the current moving from a normally closed position to an open position and closes with the sets of primary contacts separated. One of the secondary contact assemblies is stationary and the other of the secondary contact assemblies has a movable contact arm, capable of rotating about a pivot and polarized by the spring to a normally closed position such that, in response to a Overcurrent condition exceeding a predetermined level, the movable contact arm rotates away from the closed position normally against the bias of the spring until the overcurrent condition falls below the predetermined level, at which time the arm Movable contact rotate to the normally closed position. According to another embodiment of the present invention, a circuit breaker includes a pair of primary contact assemblies, a pair of secondary contact assemblies, a spring, and a linking member. At least one of the primary contact assemblies is constructed and is arranged to interrupt the current moving from a normally closed position to at least one open position, and at least one of the secondary contact assemblies is / - polarized by the spring toward a normally closed position and is able to rotate around a pivot away from the normally closed position against the polarization of the spring. The linking member, which is coupled to one of the primary contact sets and one of the secondary contact sets, causes one of the secondary contact sets to rotate around the pivot in response to one of the primary contact sets being move from the normally closed position. The above summary of the present invention is not intended to represent each embodiment, or each aspect, of the present invention. This is the purpose of the figures and the detailed description that follows. BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages of the invention will become apparent upon reading the following detailed description and with reference to the drawings, in which: Figure 1 is an illustration of a circuit breaker, in accordance with the present invention, with the cover of the circuit breaker removed so as to illustrate the components inside the circuit breaker; Figure 2 is an illustration of the circuit breaker of Figure 1 with certain components removed so as to illustrate the current path through the circuit breaker; ~ - Figure 3 is an illustration of the circuit breaker of Figure 1, with certain components removed in order to illustrate the firing mechanism; Figures 4a and 4b are perspective illustrations of the primary blade, according to the present invention, used in the circuit breaker of Figure 1; Figure 5a is an illustration of a middle terminal and a guide rail member, according to the present invention, used in the circuit breaker of Figure 1; Figure 5b is an illustration of an alternative middle terminal arrangement and guide rail member, in accordance with the present invention, which may be used in place of the components shown in Figure 5a; Figure 6 is an amplified illustration of an alternative middle section that can be used in place of the structure shown in Figure 1; and Figure 7 is an illustration of an alternative circuit breaker, in accordance with the present invention, using an array of components similar to that shown in Figure 1, but using a cam / spring arrangement in the secondary section. Although the invention is susceptible to various modifications and alternative forms, a specific embodiment thereof has been shown as an example in the drawings and will be described in detail. However, it should be understood that it is not intended to limit the invention to the particular form described, On the contrary, the intention is to cover all modifications, equivalents, and alternatives that fall within the spirit and scope of the invention. , as defined by the appended claims, Detailed Description of the Figures Although the present invention can be used in a wide variety of residential, commercial and industrial applications, the implementation of the present invention shown * ~ in Figure 1 is ideally suited for applications that require high performance, low cost, and simplicity of design in a small package The circuit breaker of figure 1 includes a housing (including base 10 and cover 11) that has numerous compartments of components (in the form of molded protuberances) to retain the internal components of the circuit breaker, most of which reside in a primary section 12 or in a secondary section 14. Although there is no definitive line of distinction between the primary and secondary sections, a conductive middle terminal 15 may be used to generally delineate the components in the primary section 12 (to the right of the middle terminal 15) and the components in the secondary section 14 (to the left of the middle terminal 15). The current path through the circuit breaker is best viewed with reference to FIG. 2, which shows the circuit breaker of FIG. 1 with certain components removed for illustrative purposes. The current path begins within the secondary section 14 at a line terminal 16. The line terminal 16 includes a conventional line block (or nipple) 17 for grasping the line wire within an opening (not shown) therein. . From the line terminal 16, a flexible conductor (or pigtail) 18 connects the current path to a secondary blade 20 capable of rotating, which, together with a secondary blade contact 22 and a stationary mating contact 24 , are used to establish a pair of contact sets for the secondary section 14. From the stationary contact 24, the current flows through the middle terminal 15 to a pair of contact sets for the primary section 12, including a stationary contact 28 and a primary blade contact 30, capable of rotating, mating. The stationary contact 28 is attached to a primary blade 32, which rotates about a blade pivot 33 in response to a firing mechanism (illustrated and discussed with respect to Figure 3). The current flows through the stationary and movable contacts 28 and 30, through the primary blade 32, and towards one end of a primary flexible connector (or pigtail) 34. The other end of the primary flexible connector 34 is attached to a bi-metal member 36, * "" ~ - which provides the thermal trip characteristics for the circuit breaker. Finally, the current flows from the bi-metal member 36 through a charging terminal and out of the charging end of the circuit breaker via a terminal (or nipple) block 40. The middle terminal 15 is "S" shaped. and is arranged with respect to the secondary and primary blades 20 and 32 to form a U-shaped conductive path for each pair of contact assemblies. Such a "U" shaped construction is used to form an electromagnetic blasting force sufficiently intense to separate each pair of contacts in response to an overcurrent condition of sufficient magnitude For additional information regarding the manufacture and operation of the middle terminal 15, reference will be made to United States Patent Application No. 07 /, entitled "Mid Terminal for a Double Break Circuit Breaker" (CRC-16 / SQUC114), filed simultaneously with the present, and assigned to the same assignee (incorporated herein by reference). With reference to Figures 1 and 3, the primary section of the circuit breaker also includes a trigger lever 42, a handle 44, a magnetic armature 46, a primary arc stack 47 and an anvil 50. These components are used to implement manual on / off operation, thermal trip separation, and electromagnetic trip separation of the primary contacts 28 and 30. The normal operation of turning on and off the primary blade 32 occurs in response to the rotation of the handle 44 in a movement in the sense of the hands of the clock or the opposite direction. In response to the rotation of the handle 44 in either direction, the primary blade 32 opens or closes the circuit via the primary movable contact 30 and the primary stationary contact 28. The rotation of the primary blade 32 is directly coupled to the handle 44 in interface points (or pivots) 56a and 56b (figures 1 and 5a, 5b) for the normal operation of turning on and off the primary blade 32. The secondary section is not affected by the normal operation of turning the primary blade on and off 32, and the secondary blade contact 22 and the secondary stationary contact 24 remain in the closed position. The thermal trip separation of the primary contacts 28 and 30 provides current interruption capability for all levels of current overload from zero to about 3,000 amps without operational assistance of the secondary section; that is, without requiring the secondary section to interrupt with the primary section. The primary section is ready to be fired when the handle 44 is manually turned first to the right to close the firing lever 42 by means of the magnetic armature 46 and then to the left to turn on the circuit breaker (closing the current path ). In rese to carrying a relatively high current level, via the bi-metal member 36, the magnetic armature 46 is brought to the yoke 50 to de-link the trigger lever 42, thereby causing the trigger lever 42 to rotate in the direction clockwise and primary blade 32 turn counterclockwise to the triggered position. This results in the primary blade contact 30 separating from the stationary contact 28 and interrupting the current flow. Related trigger arrangements are shown in U.S. Patent Nos. 2,902,560; 3,098,136; 4,616,199; and 4,616,200, and the United States patent application No.

Series (DC0137, filed), each of which was assigned to the assignee hereof and is incorporated herein by reference. The primary contacts 28 and 30 can also be triggered manually, for example for testing purposes, by pressing (via an opening in the upper part of the housing) the upper part of a plastic depressible member, of a part 51 (Figure 1). As shown in Figure 4, the depressible member 51 includes flexible arms 52a and 52b and a linking leg 53. The flexible arms 52a and 52b reside in triangular-shaped compartments 35a and 35b (Figure 2) and, via the walls of these compartments 35a and 35b provide resilience to return the member 51 to its normal position after being depressed. The connecting leg 53 is of sufficient length so that, in response to the depression of the depressable member 51, the linking leg 53 links a wing 54a of a cam 54 (figure 1) which, in turn, rotates the cam 54 counterclockwise and causes the opposite wing 54b to link the armature 46. This releases the linkage of the firing lever 42 by means of the armature 46, thereby separating the contacts 28 and 30. The separation opened by Electromagnetic blasting of the primary contacts 28 and 30 occurs simultaneously with the separation of the secondary contacts 22 and 24 in the secondary section 14, to provide current overload protection for levels of more than about 3,000 amperes. In response to the occurrence of a current failure above 3,000 amperes, two additive forces develop in opposite directions between each set of contacts, the primary contacts 28 and 30 and the secondary contacts 22 and 24. The first force is the resistance to the constriction between each set of contacts. This provides a magnetic force that tries to separate the contacts. The second force is a result of the U-shaped configuration of the current path of the middle terminal 15 in combination with the associated contacts and the primary / secondary blade. This configuration forms a magnetic blasting loop that creates an additional contact separation force to separate each set of contacts substantially simultaneously. Within the primary section 12, the primary blade 32 is biased by means of an extension spring 60 (Fig. 1), which is attached at one end to a retaining member 62 (Figs. 5a, 5b) of the primary blade 32 and at the other end to a retaining member (not shown in Figure 1) on the firing lever 42. The firing lever 42 is closed by the magnetic armature 46. The handle 44 is used to rotate the primary blade to the position of closed contacts. A short or high level fault causes the primary blade 32 to rotate counterclockwise until the rotation is stopped by a knife stop 31 (molded as part of base 10). During this rotation, the knife interface pins 56a and 56b (figures 3, 5a, 5b) remain in the fixed position and, at the same time as the blade 32 is being opened by blasting, the firing lever 42 is disengaged and is rotating counterclockwise. The handle 44 and the knife interface pivots 56a and 56b move only after the trigger lever 42 has moved sufficiently to pull the blade 32 out of position, which occurs after the blade 32 returns to the closed contacts position. For more information concerning the primary blade 32, reference may be made to the United States patent application No., entitled "High Current Capacity Blade" (CRC-12 / SQUC115), filed simultaneously with the present, assigned to the same. assignee, and incorporated in the preseijte by reference. Within the secondary section 14, the collective separation force causes the secondary blade 20 to rotate counterclockwise about a pivot 49 to overcome the force of an extension spring 48 (FIG. 1), causing the extension spring 48 to stretch. The extension spring 48 allows the secondary blade 20 to continue opening as long as the force to open the blade is greater than the extension force of the spring 48. In this way, when the force of separation is reduced to a level that is less than the extension force of the spring 48, the spring 48 returns the secondary blade 20 to its normally closed position. Except for the extension spring 48, the only other component acting on the secondary blade 20 is an optionally used guide rail 61, which separates the contacts 28 and 30 slightly in response to a "trip" (by the trigger lever 42). ) in order to prevent the over-corrie condition from welding the contacts 22 and 24 together. The guide rail 61 is a component of elongated plastic, which resides in a hole through the center of the middle terminal 15, having one end that tcpa at an extension 63 (figure 3) on the trigger lever 42, and another end abutting in the secondary blade 20 just below the secondary contact 22. In this way, in response to a triggered condition, the firing lever 42 rotates about a pivot 65, causing the extension 63 to link the guide rail 61 which , in turn, responds by hitting the secondary blade 20 and keeping it at a non-substantial distance (about 0.025 in) away from its normally closed position. For additional information concerning the structure and operation of the guide rail 61 and the extension spring 48, as well as their alternative implementations, you may refer to the United States patent application.

United No., entitled "Double Break Circuit Breaker Having Improved Secondary Section "(CRC-13 / SQUC118), filed simultaneously with this, assigned to the same assignee, and incorporated herein by reference, the spring 48 and the blade 20 are therefore the only substantially active components in the secondary section, and this two-component arrangement does not require traditional current-limiting components connected to the blade 20 to absorb the arc energy current that results from a separation of the contacts 22 and 24. Rather, this current is minimized by the simultaneous separation of the contacts in the primary section The arc energy that develops between the contacts of the secondary section is absorbed by a secondary arc stack 66 (Figure 1) Figure 5b illustrates an alternative arrangement for the middle terminal 15 of Figures 1 and 5a In this arrangement, an average terminal 15 'is identical to the middle terminal 15 except that the opening in it, to receive the guideway 61, it is open all the way to the edge of the middle terminal 15 '. This facilitates the assembly because it is easier to build using automatic "Z" axis equipment. However, from an operational point of view, the arrangement of FIG. 5 a is preferred because the medium 15 isolates the primary section of the secondary section against sparks and debris. Figure 6 illustrates yet another alternative for separating contacts 22 and 24 as a reaction to a trip. The firing lever 42 is pivoted from the pivot point 65 of the firing lever and is polarized in the clockwise rotation by a primary spring (not shown) which is attached to the spring hook 74 of the trigger lever. The other end of the spring hook is attached to a primary blade hook (62 of Figures 4a, 4b). The firing lever 42 is held in its stationary position by the armor (46 of Figure 3). When the firing lever is disengaged from the armature, the firing lever 42 is rotated in a clockwise motion, causing a rotary guide rail 78 to rotate (secured to it) in the same direction. address and hit the secondary blade to separate the contacts 22 and 24. More specifically, the rotatable guide rail 78 is secured via a male attachment point 80 which is positioned towards a mating hole in the firing lever. The rotating guide rail 66 has an extending arm surface 82 that links a smooth cam surface 84 on the secondary blade 20. When a fault occurs, the firing lever 42 is released and begins to rotate in the clockwise direction of the clock. The spring force on the hook 74 takes control and continues to rotate the trigger lever in the clockwise position. The extension point 82 of the rotating guide rail engages the cam surface 84 of the secondary blade and begins to rotate the secondary blade 20 in a counterclockwise rotation. As with other aspects of the circuit breaker of Figure 1, this rotating guide rail arrangement is also assembled on the "Z" axis. Within the primary section 12, the arc voltage which is generated upon separation of the primary contacts 28 and 30 is guided outside the circuit breaker by an arc transfer blade 67, a primary arc stack 68 and a sliding fiber element. , arc reflector 69. The blade 67 is positioned sufficiently close to the sweep radius of the contact 30 so that it can accommodate lower level fault currents in the circuit breaker, which is important because the secondary blade does not operate in response to lower level faults. Upon passing the contact 30 immediately to the nearest part of the arc transfer blade 67, the arc jumps to the surface of the blade 87, which provides the arc with a linear path through the arc stack and prevents the arc from re-lighting between the contacts 28 and 32. In this way, the arc energy is guided outward to the load terminal 38 along the arc transfer blade 67. At higher energy levels, the arc transfer blade 67 reduces stress on the bi-metal member 36 by diverting current from it and into the arc transfer blade 67. The sliding fiber 69 produces gaseous ions which help to propel the energy of the arc towards the arch stack 68. Because both sets of contacts separate simultaneously, the combination of the arc voltages within the secondary arc stack 66 and the stacking of primary arc 68 results in these voltages being additive. This provides a very rapid rise in arc voltage and also allows the generation of high levels of arc voltage within the disclosed circuit breaker, as is required in many applications that require double-break circuit breakers. For additional information concerning the primary and secondary arc stackings 66 and 68 and the manner in which the arc energy is shielded from the contacts, reference may be made to U.S. Patent Applications Nos. (CRC). 14 / SQUC113) and (CRC- '- 21 / SQUC116), respectively entitled "Are Stack for a Circuit Breaker" and "Blade Transíer Are Shunt", presented simultaneously with this, assigned to the same transferee, and also incorporated in the present by reference. Calibration of the thermal firing characteristics is carried out by adjusting a calibration screw 72 (Fig. 1) to fix the proper position for the bi-metal member 36. The charging terminal 38 is connected to the bi-metal member 36. so that when the calibration screw 72 is turned clockwise, the calibration screw 72 pulls the middle part of the loading terminal 38 towards the head of the calibration screw 72. In this way, both the yoke 50 as the armature 46 can be moved toward or away from the loading terminal 38 for proper reading. For additional information regarding this calibration process as well as additional details of the loading terminal 38, the bi-metal member 36 and the depressible member 51, reference may be made to the United States patent application Serial No., entitled "Circuit Breaker Having Double Break Mechanism" (CRC-11 / SQUC112), presented simultaneously with the present, assigned to the same transferee, and incorporated herein by reference. Figure 7 illustrates an alternative way of implementing the biasing force on the blade 20 in the secondary section 14 of the circuit breaker of Figure 1. The secondary blade 90 of Figure 7 is very similar to the secondary blade 20 of the figure 1, but the secondary blade 90 uses a blade cam 92 and a torsion spring 94 instead of the extension spring 48 of Fig. 1. The torsion spring 94 generates a torsion about a spring pivot 96. This torsion is viewed at the spring end 98, which is at an interface with the cam 92 at a touch point 100. This torque exerts a force in one direction to rotate the cam 92 about the cam pin. At an interface point 102, cam 92 links the secondary blade at its end. The force provided to the secondary blade 90 transmits a force in the direction of the arrow A shown in Fig. 7. This force results in a twist on the secondary blade 90 to try to rotate it towards the contact 24 about the pivot 104 of secondary blade. If this blade were in the upper position, as shown, without applied current, the blade would rotate counterclockwise until the movable and stationary contacts were closed. By rotating the blade 90 in this way, the end of the secondary blade travels along the cam surface starting at point 102 and ending at interface point 106. At interface point 106, contacts 22 and 24 are closed and the contact pressure at terms of the strength in the contacts is in their work value. In the reverse mode, when the blade is opened by blasting by a high fault current, the interface point starts at point 106 and ends at point 102. When the blade rotates in this direction, the torsion on the secondary blade 90 will begin to reduce when opening the blade to its fully open position. This is a distinctive advantage over other suspensions. Another advantage of this design is the small area that is required for the torsion spring 94 that generates the energy for the contact force. If an extension spring were attempted in this particular design, the package would require more space due to the length of the extension spring. This arrangement requires less force on the secondary blade when rotating to the open position, and can be implemented using assembly on the "Z" axis. Accordingly, a double break circuit circuit breaker, which incorporates the principles of the present invention, has been described, which provides superior level performance in terms of interruption with independent operation of the primary and secondary blades for a simple design and better stability. resistance when used in switching tests. The overall impact is lower product cost with higher performance than any previous circuit breaker design. Those skilled in the art will readily recognize that various changes and modifications to the present invention may be made without departing from its true spirit and scope, which are set forth in the following claims.

Claims (10)

1. CLAIMS What is claimed is: 1. A circuit breaker for passing current during a normal condition and, in response to at least one abnormal condition, interrupting the current, comprising: a pair of sets of primary contacts, at least one of the sets of primary contacts being constructed and being arranged to interrupt the current by moving from a normally closed position to an open position; a linking member that provides a linking force in response to movement from the normally closed position; a spring; and a pair of sets of secondary contacts, one of the sets of secondary contacts being stationary and the other of the sets of secondary contacts having a movable contact arm coupled to the linking member and capable of rotating about a pivot and polarized by the spring towards a normally closed position such that, in response to an overcurrent condition exceeding a predetermined level, the movable contact arm rotates away from the normally closed position until the overcurrent condition falls below the predetermined level , upon occurrence of which the movable contact arm rotates towards the normally closed position and, in response to the engagement force, the movable contact arm rotates away from the normally closed position.
2. 2. A circuit breaker, according to claim 1, wherein the spring is an extension spring.
3. 3. A circuit breaker, according to claim 2, wherein the extension spring has an end secured to the movable contact arm.
4. 4. A circuit breaker, according to claim 1, further comprising a conductive plate having a first portion constructed and arranged as a pair of the first pair of contact assemblies and having a second portion constructed and disposed as part of said assembly. Secondary secondary contacts.
5. 5. A circuit breaker, according to claim 1, wherein the movable contact arm is constructed and arranged to interrupt the current by rotating away from the normally closed position in response to an opening force by blasting.
6. 6. A circuit breaker, according to claim 5, wherein the movable contact arm rotates a considerable distance away from the normally closed position.
7. A circuit breaker, according to claim 5, wherein the movable contact arm rotates a considerable distance away from the normally closed position only in response to the blast opening force.
8. A circuit breaker, according to claim 7, wherein said at least one of the primary contact assemblies and said movable contact arm of the secondary contact assemblies interrupts the current in response to the blast opening force by moving in substantially simultaneous form.
9. 9. A circuit breaker, according to claim 1, wherein the spring is disposed in a first plane and the movable contact arm is disposed in a second plane that is different from the first plane. A circuit breaker, according to claim 1, wherein the pair of primary contact sets and the pair of secondary contact sets are respectively located in first and second sections, said first and second sections constructed and arranged to substantially isolate the pair of primary contact sets of the pair of secondary contact sets.