摘要:
A molded case circuit breaker having a trip unit with one or more integrally formed dielectric protrusions that are configured to slidably interconnect with corresponding dielectric members of the base when the trip unit is secured to the base. The dielectric protrusions extend from dielectric walls located between adjacent enclosure chambers that house the current transformers and are configured to remain in contact with the dielectric members of the base as the trip unit is being moved with respect with the base. By remaining in contact to one another while the trip unit is moved with respect to the base, the dielectric protrusions, along with the dielectric members, maintain a strong dielectric barrier within the exterior spaces between the CT enclosure chambers, thereby preventing debris from traveling between and accumulating on the trip unit and the base.
摘要:
A divided armature for the trip mechanism of a circuit breaker especially useful for low trip current breakers allows for two independent adjustments: first of the magnetic air gap between the yoke and the armature and second of the clearance between the trip bar and the back plate of the armature. The divided armature allows the force of a return spring of the trip mechanism to be unchanged while adjusting the magnetic air gap to set the trip current point.
摘要:
A multi-pole circuit breaker comprising a single main housing containing multiple circuit breakers for protecting multiple branch circuits. Each of the circuit breakers comprises a single line terminal for receiving electrical current from a utility line, a plurality of load terminals for supplying electrical current from the single line terminal to a plurality of branch circuits via load lines, and a plurality of neutral terminals for receiving electrical current returned from the branch circuits via neutral lines Line conductors inside the main housing connect the line terminal to the plurality of load terminals. Sensors inside the main housing generate signals representing characteristics of the electrical current flow in the branch circuits, and a signal processor uses the signals generated by the sensors for detecting abnormal conditions in the branch circuits and generating trip signals in response to the detection of an abnormal condition. A single tripping mechanism between the line terminal and the load terminals receives the trip signals and interrupts the flow of current to the branch circuits in response to a trip signal.
摘要:
A divided armature for the trip mechanism of a circuit breaker especially useful for low trip current breakers allows for two independent adjustments: first of the magnetic air gap between the yoke and the armature and second of the clearance between the trip bar and the back plate of the armature. The divided armature allows the force of a return spring of the trip mechanism to be unchanged while adjusting the magnetic air gap to set the trip current point.
摘要:
A multi-pole circuit breaker comprising a single main housing containing multiple circuit breakers for protecting multiple branch circuits. Each of the circuit breakers comprises a single line terminal for receiving electrical current from a utility line, a plurality of load terminals for supplying electrical current from the single line terminal to a plurality of branch circuits via load lines, and a plurality of neutral terminals for receiving electrical current returned from the branch circuits via neutral lines Line conductors inside the main housing connect the line terminal to the plurality of load terminals. Sensors inside the main housing generate signals representing characteristics of the electrical current flow in the branch circuits, and a signal processor uses the signals generated by the sensors for detecting abnormal conditions in the branch circuits and generating trip signals in response to the detection of an abnormal condition. A single tripping mechanism between the line terminal and the load terminals receives the trip signals and interrupts the flow of current to the branch circuits in response to a trip signal.
摘要:
A flexible amperage flag that indicates an amperage rating of a trip unit in a circuit breaker. The flag is molded with a housing of the trip unit so that it remains with the trip unit even when installed into a different circuit breaker. The flag includes an attachment member secured to a wall of the trip unit and a flexible leg integral with the attachment member. A top surface member indicates the amperage rating and protrudes through an auxiliary cover of the circuit breaker so as to be visible through the panelboard into which the circuit breaker is installed and is connected to the top surface member. During a circuit interruption, the pressure created by the exploding gas forces the auxiliary cover away from the trip unit, creating stress on the flag. The flexible leg permits the flag to move with the auxiliary cover and return to its original form without breaking. The flag can also include a second leg that prevents movement of a hammer of the trip unit out of its pre-assembled position during assembly of the circuit breaker.
摘要:
A divided armature for the trip mechanism of a circuit breaker especially useful for low trip current breakers allows for two independent adjustments: first of the magnetic air gap between the yoke and the armature and second of the clearance between the trip bar and the back plate of the armature. The divided armature allows the force of a return spring of the trip mechanism to be unchanged while adjusting the magnetic air gap to set the trip current point.
摘要:
A user adjustment assembly for translating user-adjustable dial settings to tripping levels of an electronic trip unit includes a potentiometer and an adjustment button. The potentiometer is positioned inside a cover of the trip unit and includes a potentiometer button. The adjustment button is coupled to the potentiometer for mechanically adjusting it and includes an insulation disc for increasing resistance to electrostatic discharge, preventing contaminants from entering the printed wire assembly components, and preventing application of downward force to the potentiometer button. The insulation disc has a bottom surface that is dimensioned to be larger than the potentiometer button. The adjustment button includes one or more stops that trigger a fail safe operation mode where the tripping levels are automatically adjusted to higher or predetermined protective levels when the adjustment button is moved to those stop positions. Switch calibration is obviated and the simplified design reduces overall cost.
摘要:
A highly accurate current sensing transformer, such as an external neutral current transformer (ENCT), accommodates a wide range of loads. The ENCT includes a housing, first and second terminals each having an end portion extending from and external to the housing, a conductor for carrying a current to be measured, and a current sensor having an aperture for receiving the conductor and having a central axis. The conductor joins the first and second terminals to form a current path that passes through the aperture. Increased accuracy is achieved by arranging the conductor such that a portion thereof passing through the aperture forms a substantial angle relative to the central axis, such that the entry angle of the current path via the conductor through the aperture of the current sensor of the ENCT matches an entry angle of a conductor through an aperture of a current sensor in the electronic trip unit to which the ENCT is attached. Other features resist rotation of the terminals during attachment of the ENCT and allow the ENCT to receive any of a variety of different lugs or terminal nuts, enabling easy attachment.
摘要:
For use within an electrical distribution to control current paths through a plurality of associated circuit breakers, a circuit arrangement comprises a plurality of circuit breakers, each having a status related to open contact position and a closed contact position. An informational display is included within the load-center to display the plurality of statuses at a user access side of the display, and a control circuit, coupled to the circuit breakers and the informational display, automatically monitors the contact status of the circuit breakers and drives the informational display so that a display of the statuses is provided.