NATURE OF THE INVENTION

This invention relates to the field of protective devices particularly current limiting magnetic circuit breakers and most particularly for the magnetic circuit breaker component for a motor control center including a contactor and a thermal circuit breaker.

BACKGROUND OF THE INVENTION

Circuit breakers as such have long been known either as discrete components or as a portion of an integrated motor controller. A magnetic circuit breaker must interrupt a fault current and dissipate the heat generated during ^' the interruption process. A current limiting magnetic circuit breaker limits current by interrupting the fault current before it can fully develop. The heat dissipation requirements can require larger circuit breakers for the ability to absorb and dissipate heat. The amount of heat generated is generally proportional to the duration of any arc generated during the interruption process and the amount of current carried in that arc. Among the patents issued in this area is U.S. Patent 4,118,608 issued to Frank W.

Kussy et al on October 3, 1978 describing a TRIP INDICATOR. Frank W. Kussy has alone and with others, a number of patents published in this area of technology. Also known are protective devices involving rotary action of a knob to activate an on or off operation such as that believed to be sold by Telemecanique, under their INTEGRAL 32 name, controls circuit continuity with holding contacts. Also publicly used is the Klockner-Moeller Model PKZ-2, which is believed to have a rotary acting mechanism with high speed current sensing solenoids with direct actions on the contacts. This breaker uses a gear driven spring loaded ove center mechanism. Additional improvement is desirable in the circuit breaker area to reduce the time of interruption and the amount of heat that is generated during the interrupting process Low dissipation in a breaker allows compactness.

SUMMARY OF THE INVENTION

The low dissipation compact circuit breaker of the present invention selectively conducts breaker current in a circuit to be protected. The compact circuit breaker is in an enclosure surrounding at least a stationary contact and a moveable contact. This moving contact selectively assumes one of two bistable states, a contiguous closed state or a noncontiguous open state.

A rotary operator means selectively causes the stationary conta and the moveable contact to assume either a closed or an open state. Sensing trip means for sensing breaker current causes t rotary operator means to move the contacts from a closed state an open state. Additionally, the sensing trip means directly acts to cause contacts to begin to assume an open state in a tr operation, if breaker current reaches a preselected trip value the faulted phase. The rotary operator means causes the contac to move from a closed to an open position by initiating a trip operation.

BRIEF DESCRIPTION OF THE DRAWING

Figure 1 is a non-integrated protective mechanism for a motor starter including the low dissipation compact circuit breaker of the present invention.

Figure 2 is a perspective view of the motor starter circui of Figure 1 with the compact circuit breaker of the present invention separated from the remaining components.

Figure 3 is a plan view of the face of the compact circuit breaker.

Figure 4 is a sectional view along the lines 4-4 of Figure 3.

Figure 5 is a sectional view along the lines 5-5 of Figure 4.

Figure 6 is a sectional view along the lines 6-6 of Figure 4.

Figure 7 is a perspective view of the compact circuit breaker of the present invention with portions of the enclosure broken away with elements missing for clarity.

Figure 8 is a partially exploded view of the compact circui breaker of the present invention.

Figure 9 is a depiction of the front panel of the compact circuit breaker of the present invention in the process of movin between a contact open position to a contact closed position.

Figure 10 is a cross section of the compact circuit breaker of Figure 9 in a manner similar to Figure 5.

Figure 11 is a cross section view of Figure 9 in the manner of Figure 6.

Figure 12 is a perspective view of the compact circuit breaker with the enclosure partially removed as is Figure 7.

Figure 13 is a side elevation of the compact circuit break of Figure 9 with the enclosure partially broken away.

Figure 14 is a front elevation of the compact circuit breaker illustrating the very last portion of movement to bring the contacts into the on position.

Figure 15 is a cross section view of the compact circuit breaker of Figure 14 in the manner of Figure 6.

Figure 16 is a cross section view of the compact circuit breaker of Figure 14 along the lines 16-16.

Figure 17 is a simplified cross section view of the present invention shown in Figure 14 in the manner of Figure 5.

Figure 18A is a cross section view illustrating the interna operating components of Figure 17 at the beginning of a knob initiated off movement.

Figure 18B is a continuation in movement of Figure 18A showing the internal components of Figure 18A as the turning off process continues.

Figure 19 is a cross section view similar to Figure 4 showing the contacts in transition to the open position.

Figure 20 is a similar view showing a portion of the internal mechanism of the compact circuit breaker when the contacts are in an on position.

Figure 21 is a cross section view showing the internal mechanism of the compact circuit breaker during a trip operation moving the contacts to an open position.

Figure 22A is a view of the internal mechanism illustrated in Figure 18A showing that mechanism towards the end of a trip operation.

Figure 22B is a partial view of the front of the compact circuit breaker of the invention showing the knob reflecting a trip operation.

Figure 23 is a exploded view of the solenoid components of the present invention along with components associated with the solenoids.

Figure 24 is an exploded view continued from Figure 23 showing components of the compact circuit breaker more closely associated with the contacts.

Figure 25 is a cross sectional view of a moving contact an components most closely associated with the moving component.

Figure 26 is a perspective view of a contact mounting spri and its spring seat.

Figure 27 is a perspective view of the spring seat of Figu 26 from a bottom perspective.

Figure 28 is a cross sectional view along the line 28-28 of

Figure 26.

Figure 29 is a top plan view of the spring seat of Figure 26.

Figure 30 is an exploded view showing a portion of the breaker of the present invention with an auxiliary switch.

Figure 31 is a cross section view of Figure 30 along the lines of 31-31.

Figure 32-A is a exploded view of the switch of Figure 31. Figure 32-B is a perspective view of a moving contact carrier component of the switch of Figure 31.

Figure 33 is a perspective view of the breaker of the present invention in association with the auxiliary switch with the enclosure of the breaker broken away to show the inner- connection between the two.

Figure 34— is an abstracted view of compact circuit breaker components of Figure 33 which activate the auxiliary switch, and the auxiliary switch.

Figure 34-B has a view of the components when the compact circuit breaker is tripping.

Figure 34-C is a view of the compact circuit breaker and components when the breaker is manually turned to the off condition.

Figure 35 is a depiction of the breaker of the present invention with the auxiliary switch interacting with a portion of

the breaker to give an indication of the on off status of the breaker.

Figure 36 is a view of the breaker and auxiliary switch wh the breaker is in an off position.

Figure 37 is an abstracted view of the breaker of the present invention including its lockout tab.

Figure 38 is a similar view to that of Figure 37 with a lockout tab in a blocking or lockout position.

Figure 39 is a perspective view of the trigger.

Figure 40 is a cross section view taken along Line 40-40 of Figure 39.

DETAILED DESCRIPTION OF THE DRAWING

Figure 1 illustrates the compact circuit breaker 10 of the present invention in association with customarily associated units being a contactor 12 and thermal circuit breaker 14. Circuit breaker 10 of the present invention is a magnetic circui breaker designed to interrupt faults in the circuit including th breaker of moderate value exceeding a preselected trip value. Contactor 12 is typically used as a remote operated switch to

turn an associated protected motor on and off. Thermal circuit breaker 14 is intended to interrupt low level faults.

Figure 2 shows circuit breaker 10 in isolation from associated components. Contactor 12 and thermal breaker 14 and particularly shows stabs 16 particularly configured to join breaker 10 to a particular contactor 12. Stabs or tangs 16 come in a number of particular configurations to insure that circuit breaker 10 and contactor 12 are a suitable match. Contactor 12 comes in a variety of ratings and only those ratings suitable fo use with a particular circuit breaker 10 can be used with circui breaker 10 because of the stabs 16 configuration since a stabs 16 are spaced to fit only one rating of a family of potential contactors.

Line terminals 18 (Figure 23) include a conventional planar tab 20 which has an unconventional side notch 22 interfacing with a portion of enclosure 24 to prevent inadvertent withdrawal of line terminal 18 in the process of connecting conductors to the line side of breaker 10. Enclosure 24 includes top housing 26, bottom housing 28 and middle housings #1-4, 30-36 respectively. The enclosure outside surfaces are top housing 26, bottom housing 28, middle housing #1/30 and middle housing #4/36. Notches 22 engage associated portions of middle housings 30-34. Between load terminal stabs 16 and line terminal 18 are a pair of contacts for each phase, namely a stationary contact 38 and a

moveable contact 40 each having a pair of conformal contact points 42. Magnetic enhancers 39 may be used in stationary contacts 38. A contiguous closed state for contacts 38,40 is shown in Figure 16. Similarly, a noncontiguous open state between contacts 38,40 is shown in Figure 4. A single trip solenoid 44 (Figure 23) senses current in a respective phase an initiates a trip operation when the current in the phase exceed a preselected trip value of the breaker current whether the breaker current exceeds the trip value by a large margin or by a lesser margin.

Solenoids in some ranges of trip current values may be advantageously double wound with a bifilar winding 46 to minimiz winding diameter which is illustrated in Figure 23. Free end 48 of the winding for solenoid 44 is connected to stationary contacts 38. The opposite end of the winding for solenoid 44 is connected line terminal 18. Nuisance trips about a trip value may be a problem with some motors. To reduce the number of nuisance trips, solenoid frame 50 is of a non uniform cross section to cause saturation near the trip value of the breaker. Finite element analysis may be used to determine appropriate frame dimensions to cause saturation, typically, about 10 times for load motor current. In the event that saturation is not achievable, a typical inertial delay may be inserted, as is well

known to those skilled in the art. The trip value for each solenoid 44 is individually adjustable at the factory with individual trip value screw 52. Individual trip value screw 52 passes through trip adjustment beam 54 in an individual orifice A user of circuit breaker 10 may adjust a central beam adjustme screw 56 which adjusts the beam so that all individual trip values are changed to another common value. Each individual tr screw 52 bears against a respective trip adjustment lever 58 to adjust the degree of preload through adjustment spring 60.

Adjustment spring 60 extends between spring cup 62 in trip adjustment lever 58 to brim 64 surrounding the upper circumference of plunger hat 66. A conventional solenoid return spring 67 totally contained within the body acts in opposition t the adjustment spring 60. Activation of solenoid 44 by a trip current causes the hat 66 to move towards the plunger frame 50 which causes brim 64 to interact with a contact lever and move the contacts to an open position in a trip operation. Brim hat 66 and brim 64 are withdrawn towards solenoid frame 50 by means of solenoid shaft 68 passing through a shaft orifice 70 and solenoid frame 50. Magnet sticking forces and friction between solenoid shaft 68 and solenoid frame 50 can be reduced by making shaft orifice 70 with a plurality of dimples about the circumference of shaft orifice 70. As conveniently seen in Figure 4 and 15, minimum penetration of individual trip screws 52 into trip adjustment beam 54 will result in a maximum current

setting for breaker 10, if trip adjustment beam 54 is distant from trip adjustment lever 58. Tamper plug 72 may be used to block access to beam adjustment screw 56 and once removed cann be replaced indicating that an attempt has been made to change the setting of breaker 10. Attempts to remove tamper plug 72 from access hole 74 results in sufficient distortion of tamper plug 72 to prevent its replacement. Each trip adjustment leve 58 is pivotally supported by a pivot shaft 76 near the apex of the triangular adjustment lever 58 above an angled adjustment face 78 distant from said spring cup 62. Individual trip scre 52 in cooperation with trip adjustment levers 58 and trip adjustment beam 54 act as individual adjustable trip level mea for individually varying the trip level of a given phase. Cooperatively the individual adjustment trip level means for a phases with beam adjustment screw 56 act as circuit breaker adjustable trip level means for simultaneously varying the tri level of each trip solenoid to set a common trip level for the breaker.

Moving contacts 40 are each guided on an individual conta carrier 80. As a fault on a phase occurs brim 64 impacts agai contact lever train member trigger 82, initiating a trip operation through the remainder of contact lever train. Shortl thereafter, brim 64 impacts against solenoid bell crank 84

causing bell crank 84 to directly act on the faulted contact carrier 80. The rotary operation means is then allowed to open the contact. Sensing trip means for sensing breaker current, causing the rotary operation means to move the contact from a closed state to an open state and for directly acting to cause the contacts to begin to assume the open state in a trip operation when the breaker current reaches a preselected trip value is provided by the cooperation of a number of elements. These cooperating elements include solenoid 44 and its components contact carrier 80, trigger 82 and solenoid bell crank 84.

Although the faulted phase initiates movement to open all the contacts through trigger 82, solenoid bell crank 84 by having lower inertia and directly acting on the associated contact carrier acts to open the faulted contact phase first. Thereafter, the remaining contacts are opened by the trigger 84 initiated movement. Depending upon the level of fault, the contact for the faulted phase may be already open due to magnetic forces by the time bell crank 84 initiates movement by the associated contact carrier. The magnetic forces are generated by a convoluted current path between moveable contacts 40 and stationary contact 38. Contact carriers 80 include a chisel point end 86, a bell crank end 88 and a solenoid bell crank indentation 90 adjacent chisel point end 86. Moveable contact 40 is slidingly fitted onto

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chisel point end 86 and is retained in place by being trapped against contact shoulder 92 and contact spring 94. Contact spring 94 fits about chisel point end 86. At an opposite skirted contact spring end 96, spring end 96 is received by spring seat 97 mounted on shorting strap 100 with a locating cross 101. Strap 100 runs between arc quencher stacks 102 to maintain an equal potential. Locating cross arms 101 are a snuggish fit in strap hold 103. when the moving contacts 40 are fully open, spring 94 is shielded from arc debris such as hot metal particles. Spring end 96 surrounds hollow reinforced post 98 and skirt 99 surrounds both spring end 96 and post 98. The open top of spring seats 97 is covered by contact 40 when contact 40 is fully open. Spring seats 97 are a shock absorbing material such as ZYTEL 101 and tend to cushion the impact of contact carriers 80 under high fault conditions. Ablation of the glass reinforced NYLON in the quencher area promotes arc cooling and more rapid interruption. It is desirable that moveable contact 40 not have a mass substantially in excess of contact carriers 80 to avoid the eventuality of moving contacts 40 rebounding from fully compressed spring 94 and substantially impeding the downward movement of contact carrier 80.

The low dissipation circuit breaker 10 of the invention achieves low dissipation with a variety of techniques. Among

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those techniques is the rotary operating means generally rotatin about operator shaft 104 in a first direction or plurality of parallel axis and a contact lever train operating in a second direction or second plurality of parallel planes. Additionally, a number of miscellaneous members generally reciprocate in interacting with the shaft rotary members or contact lever train members. A significant portion of the speed with which contacts 40 move to the open position results from the low inertia of the moving members. The manner in which the shaft rotary members an the contact lever train interact further contribute to the speed and compactness of breaker 10. The plurality of shaft rotary members tend to rotate about operating shaft 104. These rotary members include the shaft rotary members are generally arcuate and often circular. These members include: hook plate 106 concentrically positioned about shaft 104; operator disk 108 also concentrically positioned about shaft 104? operator disk 108 also concentrically mounted about shaft 104,* expander 110 pivotally mounted to reset actuator 112 which

is concentrically mounted to shaft 104, and on/off disk 114 bei off cam concentrically mounted to shaft 104.

Shaft 104 in this region has a plurality of reduced diameters f the rotary members ending in a bearing diameter 116 being the smallest diameter and received in bearing hole 118 of middle housing no. 2 reference numeral 32. Opposite the end of shaft 104 having the bearing diameter 116 is knob end 120 terminating keyed squarish portion of shaft 104 which extends beyond the fa of top housing 26 to receive knob 122 which is generally elongate. Approximately midway between shaft end bearing diameter 116 and knob end 120 there is a operating lug 124 bein a rectangular stepped body extending radially from the shaft. portion of operating lug 124, step lug 125, selectively engages central aperture 126 including an operating lug surface 128 engaged by step lug 125. These shaft rotary members rotate abo a pivot axis parallel to operating shaft 104. Escapement 130 also rotates about a pivot axis 132 which is parallel to operating shaft 104. However, escapement 130 while interacting with rotary shaft members is generally U-shaped with one truncated leg 134, base 136 and plunger leg 138. On plunger le 138 is a spring receptacle 140 for mounting escapement lever return spring 142 which biases escapement lever 130 towards tri plunger 144.

Trip plunger 144 and reset lever 146 can be generally categorized as miscellaneous components which often move rectalinearly such as contact carrier 80.

Contact lever train members include trigger 82 at one end interacting with brim 64 to initiate a trip operation, a trip lever 148, trip latch 150 and bell crank 152. Bell crank 152 h a plunger arm 154 and a carrier arm 156. When contacts are to opened carrier arm 156,powered by trip springs 158 acting throu plunger 144 and plunger arm 154, is rotated into engagement wit the bell crank end 88 of the contact carrier 80 for each phase. Once initiated a trip or off operation continues until the contacts open fully. Circuit Breaker 10 operates in four (4) modes. One mode i turning on from an off position where knob handle 160 is essentially in a horizontal position 90 degrees from a vertical on position. Turning on requires that knob 122 be moved manuall into the on position generally illustrated in Figure 14, from th off position generally illustrated in Figure 3. A second operation is an off operation from a circuit breaker on position shown in Figure 14 requiring an operator to rotate knob 122 to the horizontal position and in the process opening the contacts. Another operation is a trip operation from the condition where

the breaker is on and solenoid 44 is activated causing a trip condition opening the contacts independently of manipulation o knob 122. The fourth operation is a reset operation where the knob 122 is at a 45 degree angle between the on and the off condition indicating the breaker has tripped. Reset occurs in moving knob 122 from the 45 degree position to the 90 degree position as in the later stages of an off operation. Manipulation of a knob 122 in an off operation in later stages initiates the same mechanism which causes a trip operation. Similarly, a reset operation occurs as part of an on operation once the knob is in the off position.

An on operation is illustrated in Figures 3 - 7, 9 - 17 an Figure 20. In most sectional figures some components actually present as shown in exploded views or other figures are not illustrated for purposes of clarity in showing how components work together. Figures 3, 4, 5, 6 and 7 show the breaker 10 in an off position. Figure 4 shows reset lever 146 in its blockin position where crank surface 162 on the lower portion of reset lever 146 is blocking, block surface 164 near the end of plunge arm 154. Plunger arm 154 is bearing against bell crank end 88 contact carrier 80. This blocks contacts 40, 42 in the open position as shown to the left of the drawing. Shaft recess 166 surrounds bearing boss 167 shown in Figure 23 surrounding beari

hole 118 if hold-off spring 168 is maintaining reset lever 146 the blocking or hold-off position and insuring that cam lip 17 is bearing against on/off cam 114. As long a reset lever 146 remains in a blocking position no accidental closure of the contacts can occur. If knob 122 is rotated towards the on position clockwise operating shaft 104 rotates clockwise carryi operator disk 108, hook plate 106 and on/off cam 114 in a clockwise rotation. Hook plate 106 is pivotally mounted to operator disk 108 by being pivoted on disk pivot 172 to the top housing 26 side of disk 108. Hook return spring 174 is mounted between hook post 176 on hook plate 106 and disk post 178 on operator disk 108. Spring 174 is biased to set plate hook 180 outward from shaft 104. Arcuate projection 182 limits the degr to which plate hook 180 extends outward from shaft 104. Arcuat semi-circle 184 extends toward top housing 26 end, as shown in Figure 5, of arcuate semi-circle 184 stop lug 186 protruding further towards top housing 26 limits the rotation of shaft 104 by riding in a conformal arcuate groove on the interior of top housing 26. Similar structure of arcuate protrusions, lugs and pivot pins extend to the rear of disk 108. A knob post 188 anchors one end of knob return spring 190. The opposite end of knob return spring 190 is anchored to a spring anchor 192. Knob return spring 190 tends to rotate shaft 104 in a counter clockwise direction towards an open position of the breaker

contacts 40,42. Arcuate spacer 194 rests against reset actuat 112 to allow free pivoting of expander 110 towards the top end spacer 194, cam lug 196 projects rearwardly to on/off cam 114 rests in lug notch 198 causing on/off cam to rotate with operating disk 108. Expander 110 includes an expander pivot po 200 received in actuator pivot hole 202. Expander return sprin 204 is hooked at one end to expander post 206 and at the other actuator post 208 and biases expander 110 to a minimum radius about shaft 104.

Adjacent spring post 208 is expander return spring slot 21 in actuator 112. Slot 210 as its name implies accommodates expander return spring 204. Reset actuator 112 in conjunction with reset lever 146 and expander 110 resets circuit breaker 10 by allowing the contacts to be closed and in the process storing energy in the stored energy mechanism of trip plunger 144 and trip springs 158 for opening. Actuator 112 includes a central aperture 212 bearing conformal diameter to shaft 104. A actuator stop 214 (on actuator 112) interacts with reset lip 170 (on reset lever 146) to prevent rotation of reset actuator 112 when reset lever 146 closest to shaft 104. Reset lever 146 is biased towards this anti-rotation block by hold off spring 168 preventing rotation

reset actuator 112 and blocking rotation of bell crank 152 from the blocking position. Opposite actuator pivot hole 202 to the opposite side of slot 210 is expander support surface 216. The inclined surface 218 shown in Figure 8 provides generous relief for the rotation of lever 148.

Trip cam 221 on the periphery of cam 114 engages trip lever 148 as breaker operating shaft 104 is rotated in a counterclockwise direction to turn the breaker off. Lever perimeter 224 engages reset lip 170 lifting reset lever 146 against the bias of spring 168 and lifting reset lever 146 to a nonblocking position during the latter stage of an on operation. At the earlier stages of an on operation clockwise rotation of operator disc 108 forces expander 110 outward against expande surface 226 and compressing trip springs 158. As trip plunger 144 moves to compress trip springs 158, latch lugs 228 on plunger 144 engage plunger shelf 230 (on latch 150) causing trip latch 150 to rotate (clockwise) . In turn, this causes contrary rotation in trigger 82 and compresses trigger return spring 232. As plunger 144 increasingly compresses trip springs 158, trip latch 150 rotates into a position where trip recesses 234 on trip latch 150 can engage latching lips 236 on trigger 82 (Figure 40) . Latching lips 236 are on the trigger pivot support 238 between outer brim arms 240. Brim arms 240 are impacted by brims 64, if the associated solenoid 44 is actuated. Engagement of latching

lips 236 and trip recesses 234 occurs locking the contacts in t on position as in Figure 20. At this point plunger 144 is also locked in position by latch lugs 228 and plunger shelf 230. Reset of the stored energy mechanism for opening the contacts i now complete as shown in Figure 16. Bell crank 152 prevents th contacts from closing being yet blocked by reset lever 146. As knob handle 160 continues to be rotated clockwise, operating lu 124 continues to bear against disc bearing 242 causing clockwise rotation of operator disc 108 and associated components. On off cam rotates lever perimeter 224 to lift reset lever 146 against hold off spring 168 bias as shown in Figure 15. As soon as reset lip 170 clears actuator stop 214, expander 110 and reset actuator 112 pivot towards a relaxed state about shaft 104 (Figure 15) . Shortly thereafter continued rotation of shaft 104 withdraws lever 146 from blocking bell crank 152 and allows contacts 40, 42 to close. During the on operation plunger 144 increasingly compresses trip springs 158 and plunger leg 138 of escapement 130 follows plunger surface 226. As a result, on hoo 244 approaches the periphery of hook plate 106. As contacts 40, 42 are closed, hook 180 (on hook plate 106) engages on hook 244 extending from escapement base 136. Breaker 10 is now in stable on state and will remain in that state until another operation i begun to move it to the off or trip positions where contacts 40, 42 are open. Until hooks 244, 180 are engaged release of knob

122 results in breaker 10 returning to the off position. Disengagement of hooks 244, 180 results in contacts 40, 42 opening. During a solenoid 44 initated trip as plunger 144 may move plunger leg 138 to disengage the hooks 244, 180 at any time trip springs 158 are compressed. The knob handle 160 position cannot inhibit a solenoid 44 initiated trip which is independent of handle 160 mechanism.

If a fault occurs on a given phase, the associated solenoid 44 for the faulted phase initiates a trip operation for all phases. Brim 64 is moved into engagement with trigger 82 which rotates counter clock wise to withdraw latching lips 236 from trip recesses 234 on trip latch 150 and unlock the stored energy mechanism. A five to one ratio in lever arms of trip latch 150 lowers the required force of the solenoids 44. Trip plunger moves toward operating shaft 104 releasing the stored energy in trip springs 158 and causing bell crank 152 to rotate into bell crank end 88 of contact carrier 80. Continued release of the stored energy opens those contacts remaining in a closed condition. Before the stored energy mechanism can complete opening the contacts solenoid bell crank 84 is rotated into solenoid bell crank indentation 90 on contact carrier 80 opening the contacts in the faulted phase. The low inertia of solenoid bell crank 84 directly actuating contact carrier 80 results in early interruption of the faulted phase and lower dissipation

requirements. The higher inertia and clearance tolerances of t mechanism initiated by trigger 82 results in a slower opening although trigger 82 is first actuated. Continued release of stored energy causes trip plunger 144 to rotate escapement 130 disengaging on hook 244 from hook 180 and moving trip hook 246 closer to hook plate 106. Shaft 104 then rotates to relax knob return spring 190 (counter clock wise) until hook 180 is caught by trip hook 246 after 45 degrees of rotation. At this point knob 122 provides an indication that breaker 10 is open as a result of a trip operation.

A condition window 248 in top housing 26 beneath knob 122 provides a direct view of plunger 144, which in the trip and the off position of knob 122 displays the "off" indicia 250. If breaker 10 is in the on condition an "on" indica 252 is visible due to the movement of plunger 144 to the stored energy position Release and counter clockwise rotation of shaft 124 to the trip position is sufficient to allow reset lever 146 to move int the blocking position of bell crank 152 and positioning lever 14 to allow a reset of the stored energy mechanism in a subsequent on operation. However, breaker 10 can not be turned on from a trip position. If an attempt is made to close breaker 10 from a trip position before turning knob 122 to an off position no stable condition results. Surface 214 of reset actuator 112 is not in a position acted upon by surface 170 of reset lever 146

and the turn on operation cannot be initiated. When knob 122 i released after such an attempt shaft 104 rotates counter clockwise (partially relaxing knob return spring 190) until hoo 180 catches on trip hook 246. Before the breaker can be turned to an on position, knob 12 must be rotated to the off position. The counter clockwise movement of shaft 104 brings stepped lug 125 into engagement wit operating lug surface 128 on hook plate 106. The continued counterclockwise rotation of shaft 104 results in hook 180 being withdrawn from engagement with trip hook 246 allowing further rotation of shaft 104 and associated members such as knob 122 to the full off position as best seen in Figure 5. A similar counter clockwise rotation of knob 122 and shaft 104 when the breaker 10 is in the on position has a similar effect. Stepped lug 125 again rotates hook plate 106 by engaging operating lug surface 128 and withdrawing hook 180 from engagement with hook 244. Once hooks 244 and 180 are disengaged the knob return spring 190 causes counter clockwise rotation of the entire mechanism to a stop position. Disc bearing 242 is engaged by operating lug 124 to carry the remaining shaft rotary members in a counter clockwise direction until stop lug 186 reaches the end

of the arcuate groove on the interior of top housing 26. Jus before rotation ends surface 221 of on off cam 114 causes tri lever 148 to rotate clockwise (Figure 20) . In turn trigger 8 rotated counter clockwise releasing the lock between trigger and trip latch 150. As a result, the same action as a trip operation follows. The stored energies in trip springs 158 causes trip plunger 144 to move upwards rotating bell crank 1 into contact carriers 80. Contact carriers 80 are forced downward by carrier arm 156 opening movable contacts 40. Fig 19 through 22B illustrate various aspects of trip and off operations.

Figures 37 and 38 of the application show lockout tab 25 and how it operates to prevent closing of breaker 10 when pad hole 256 is exposed. If an operator wishes to prevent closur breaker 10 when it is unattended the operator may seize grip and extend tab 254 until hole 256 is exposed. Movement of ta 254 against the bias of lockout bias spring 260 causes reset lever 146 to ride upward along reset medial ramp 262. Upper 264 of lockout indentation 266 rides along ramp 262 lifting c lip 170 clear of engagement with reset actuator 112. Since t reset actuator 112 cannot be blocked from rotation-breaker 10 cannot be turned to an on position. When lockout tab 254 has withdrawn inward, lateral arms 268 rest to either side of loc indentation 266. Medial ramp 262 provides a transition betwe

narrow height 270 and wider height 272 which lifts cam lip 170 and reset lever 146 upwards. Figures 30 through 34 illustrate the use of an auxiliary switch for two indicating functions. This switch although called auxiliary are often sold with breake 10.

Figure 30 shows a perspective side view of breaker 10 middle housing #1 reference numeral 30, including actuator tab hole 274 and mounting holes 276. Mounting holes 276 receive auxiliary locator projections 278 and auxiliary hooks 280 to snap auxiliary switch 282 into place. This same scheme is used of the other side of breaker 10 also.

Figure 31 is a cross section of auxiliary switch 282 along the line 31-31 of Figure 30. Switch 282 is shown in the actuated position with actuating tab 284 moved inward of switch front edge 286. Auxiliary contact spring 288 is compressed as is normally open contact spring 290. Normally open contacts 292 are closed. However, normally closed contacts spring 294 is extended because normally closed contacts 296 have welded. The spring loaded connection between normally closed contacts 296 and contact carrier 298 provides a yielding connection in the event that normally closed contacts 296 are welded as illustrated. If this is not done, auxiliary protuberance 300 on bell crank could lodge against actuating tab 284 (Figures 35 and 36) and prevent breaker 10 from tripping. Figures 35 and 36 are intended to illustrate

the interaction between auxiliary switch actuating tab 284 and protuberance 300 in the movement from on to off position. In event the contacts are welded, springs 290, 294 provide enough elasticity of the connection between carrier 298 and contacts 292, 296 to allow protuberance 300 to slip by. The partial enclosure of auxiliary switch 284 consists of auxiliary base 30 and auxiliary cover 303. Auxiliary cover 303 is retained on auxiliary base 301 by cover hooks 305, on auxiliary cover 303 latching on to base lips 307. Figure 32-A is an exploded view auxiliary switch 282. Figure 32-B is a perspective view of carrier 298 and associated components. The remaining component of switch 282 are relatively identifiable to one skilled in the art.

Figures 33 and 34 show auxiliary switch 282 mounted to the right side of breaker 10 where it acts as an trip indicator whi is only actuated when breaker 10 is in a trip condition. Although auxiliary switch 282 needs no modification to act as a trip indicator, internal components must be added to the interi of breaker 10. Trip switch actuator 302 is spring biased to a crank position by a trip switch lever return spring 304 as show in Figure 33. Lever spring 304 is mounted to lever 302 by leve post 306 at one end and is abutted against the interior of top housing 26 at the other. Lever 302 is of a relatively complex design having four arms as best seen in Figures 34. Two tear

dropped shape arms 308 ride in tear drop grooves 310 of adjacent middle housings. The wide base portion 312 of arm 308 provides guided reciprocal movement of lever 302. The narrow apex 314 allows pivotal movement of arm 302 as appropriate. The post 306 and arms 308 all project upward from lever 302. A continuation of upper shelf 316 is carried forward towards on off cam 114. Nearest to cam 114 shelf 316 continues as an arcuate arm 318 extending upwardly and towards the center of breaker 10. Club arm 320 descends in a downward direction from upper shelf 316 and terminates in club 322. Figure 34-A is an abstracted view of portions of the mechanism of breaker 10 and switch 282 if breaker 10 is in the on position. If breaker 10 is tripped bell crank 152 auxiliary trip lever 157 is rotated into club 322. In turn club 322 rotates into actuator tab 284 as indicated in Figure 34- B. In contrast, if knob 122 initiates an off operation, trip tab 222 impacts against the bottom of upper shelf 316 lifting and pivoting lever 302 out of position to prevent club 322 from transmitting the movement of trip lever 157 to actuator tab 284.

As those skilled in the art will readily recognize, some of the invention elements may be interchanged, for example those shown as integral may be separated or those separated may be made integral without adversely affecting the performance of the invention.

From the foregoing description it will be apparent that modifications can be made to the compact circuit breaker of the present invention without departing from the teaching of the invention. Also it will be appreciated that the invention has number of advantages, some of which have been described above a others of which are inherent in the invention. Accordingly, th scope of the invention is only to be limited as is necessitated by the accompanying claims.