Abstract: An electrical switching apparatus includes separable contacts, an operating mechanism structured to open and close the separable contacts, and a trip mechanism cooperating with the operating mechanism to trip open the separable contacts. The trip mechanism includes a trip latch, and an arc chamber operatively associated with the separable contacts. The arc chamber includes a plurality of arc plates and a barrier disposed between the arc plates and the trip latch. The barrier has an opening therein. A trip member is disposed in or about the opening of the barrier of the arc chamber. During interruption of current flowing through the separable contacts, pressure arising from an arc in the arc chamber pushes the trip member away from the barrier of the arc chamber to engage the trip latch and cause the trip mechanism to trip open the separable contacts.

Abstract: An electrical switching apparatus includes separable contacts, an operating mechanism structured to open and close the separable contacts, and a trip mechanism cooperating with the operating mechanism to trip open the separable contacts. The trip mechanism includes a trip latch, and an arc chamber operatively associated with the separable contacts. The arc chamber includes a plurality of arc plates and a barrier disposed between the arc plates and the trip latch. The barrier has an opening therein. A trip member is disposed in or about the opening of the barrier of the arc chamber. During interruption of current flowing through the separable contacts, pressure arising from an arc in the arc chamber pushes the trip member away from the barrier of the arc chamber to engage the trip latch and cause the trip mechanism to trip open the separable contacts.

Abstract: A load conductor is provided for an electrical switching apparatus, such as a circuit breaker. The circuit breaker includes a housing having a number of recesses. The load conductor includes first and second opposing sides, an intermediate portion extending between the first and second sides, and a number of protrusions extending outwardly from the second side. Each of the protrusions is disposed within a corresponding one of the recesses of the housing to secure the load conductor without a separate fastener.

Abstract: A movable arm assembly is for an electrical switching apparatus including a stationary contact and an operating mechanism. The arm assembly includes a biasing member and an arm member having a first end, an opposite second end, a pivot point therebetween, and a portion having a longitudinal axis. A movable contact is disposed at or about the first end. The arm member engages a crossbar member at or about the pivot point such that the arm member can pivot from a first position to a second position. The biasing member engages the arm member at a point between the pivot point and the second end and includes a portion that engages and biases against a housings of the crossbar member. The longitudinal axis of the portion of the arm member is oriented generally parallel to the portion of the biasing member when the arm member is at the first position.

Abstract: A load conductor is provided for an electrical switching apparatus, such as a circuit breaker. The circuit breaker includes a housing having a number of recesses. The load conductor includes first and second opposing sides, an intermediate portion extending between the first and second sides, and a number of protrusions extending outwardly from the second side. Each of the protrusions is disposed within a corresponding one of the recesses of the housing to secure the load conductor without a separate fastener.

Abstract: A handle arm assembly is for a circuit interrupter including an undervoltage release mechanism having a reset mechanism. The handle arm assembly includes a body portion rotatable through an arc between an on position, an off position, and a reset position beyond the off position and an arm portion projecting laterally from the body portion out of the plane of the arc through which the body portion rotates. The body portion and the arm portion are formed from a single piece of material wherein the body portion and the arm portion are different portions of the single piece of material. The arm portion is structured to engage the reset mechanism in a manner such that arcuate movement of the arm portion as the body portion moves to the off position is translated into actuation of the reset mechanism.

Abstract: A magnetic trip mechanism is provided for an electrical switching apparatus. The magnetic trip mechanism includes a magnetic member, an armature having opposing first and second ends and first and second sides, an armature restraint and a biasing element. The armature moves among first and second positions corresponding to separable contacts of the electrical switching apparatus being tripped open and closeable, respectively. The armature restraint includes first and second portions. In the first position, the first side of the armature engages the magnetic member. In the second position, the second side of the armature engages the second portion of the armature restraint. The armature restraint and the biasing element comprise a sub-assembly, which is removably coupled to the magnetic member. After being removably coupled to the magnetic member, the biasing element is chargeable to bias the armature away from the first position toward the second position.

Abstract: A movable arm assembly is for an electrical switching apparatus including a stationary contact and an operating mechanism. The arm assembly includes a biasing member and an arm member having a first end, an opposite second end, a pivot point therebetween, and a portion having a longitudinal axis. A movable contact is disposed at or about the first end. The arm member engages a crossbar member at or about the pivot point such that the arm member can pivot from a first position to a second position. The biasing member engages the arm member at a point between the pivot point and the second end and includes a portion that engages and biases against a housings of the crossbar member. The longitudinal axis of the portion of the arm member is oriented generally parallel to the portion of the biasing member when the arm member is at the first position.

Abstract: A handle arm assembly is for a circuit interrupter including an undervoltage release mechanism having a reset mechanism. The handle arm assembly includes a body portion rotatable through an arc between an on position, an off position, and a reset position beyond the off position and an arm portion projecting laterally from the body portion out of the plane of the arc through which the body portion rotates. The body portion and the arm portion are formed from a single piece of material wherein the body portion and the arm portion are different portions of the single piece of material. The arm portion is structured to engage the reset mechanism in a manner such that arcuate movement of the arm portion as the body portion moves to the off position is translated into actuation of the reset mechanism.

Abstract: A magnetic trip mechanism is provided for an electrical switching apparatus. The magnetic trip mechanism includes a magnetic member, an armature having opposing first and second ends and first and second sides, an armature restraint and a biasing element. The armature moves among first and second positions corresponding to separable contacts of the electrical switching apparatus being tripped open and closeable, respectively. The armature restraint includes first and second portions. In the first position, the first side of the armature engages the magnetic member. In the second position, the second side of the armature engages the second portion of the armature restraint. The armature restraint and the biasing element comprise a sub-assembly, which is removably coupled to the magnetic member. After being removably coupled to the magnetic member, the biasing element is chargeable to bias the armature away from the first position toward the second position.

Abstract: A cradle stop assembly is provided for a circuit breaker including an operating mechanism. The operating mechanism includes a pivotable movable contact arm and a cradle member which is movable between a latched position corresponding to separable contacts of the circuit breaker being closeable and an unlatched position corresponding to the separable contacts being tripped open. The cradle stop assembly includes a first member coupled to a portion of the operating mechanism, a second member disposed opposite the first member, and a generally planar stop plate extending between the first and second members. A first stop portion of the stop plate resists movement of the cradle member beyond a first predetermined position to avoid the cradle member undesirably interfering with the pivotable movable contact arm. A second stop portion resists the pivotable movable contact arm from undesirably pivoting beyond a second predetermined position.

Abstract: A cradle stop assembly is provided for a circuit breaker including an operating mechanism. The operating mechanism includes a pivotable movable contact arm and a cradle member which is movable between a latched position corresponding to separable contacts of the circuit breaker being closeable and an unlatched position corresponding to the separable contacts being tripped open. The cradle stop assembly includes a first member coupled to a portion of the operating mechanism, a second member disposed opposite the first member, and a generally planar stop plate extending between the first and second members. A first stop portion of the stop plate resists movement of the cradle member beyond a first predetermined position to avoid the cradle member undesirably interfering with the pivotable movable contact arm. A second stop portion resists the pivotable movable contact arm from undesirably pivoting beyond a second predetermined position.

Abstract: A contact assembly for a circuit breaker includes a fixed contact, a movable contact, and a movable contact arm. The movable contact arm includes a first end carrying the movable contact, a second end, and a pivot portion proximate the second end. A moving arm portion extends from the first end toward the pivot portion. The moving arm portion has a width, an upper edge, a lower edge, and a height defined by the distance between the upper edge and the lower edge. In response to a trip condition, the movable contact separates from the fixed contact and the movable contact arm pivots open at an angular opening velocity. The height of the moving arm portion of the movable contact arm is at least four times the width of the moving arm portion, thus minimizing the moment-of-inertia of the movable contact arm, and increasing the angular opening velocity.