摘要:
Electrical equipment is safeguarded from damage due to faults by a circuit that provides several levels of protection. A semiconductor switch and a current sensor are placed in series with the electrical equipment. When the current to the equipment exceeds a first threshold for a predefined period of time, the semiconductor switch is rendered non-conductive until the circuit is specifically reset. When the current to the equipment exceeds a greater second threshold, a pulsed signal alternately places the semiconductor switch in conductive and non-conductive states so that the average current applied to the equipment is within an acceptable level. Should the current exceed an even greater third threshold, the semiconductor switch is immediately rendered non-conductive until the circuit is manually reset.
摘要:
The toggle mechanism of a circuit breaker is connected at one end to the pivoted contact arm and at the other end to a pivoted latch lever which is engaged to latch the toggle mechanism by a latch member pivoted for movement in a plane perpendicular to the plane of the toggle mechanism. The latch member serves as an armature for a trip motor energized by a trip circuit responsive to an arc fault and/or a ground fault to unlatch the toggle mechanism and trip the circuit breaker open. The latch member is also tripped by a helical bimetal responsive to persistent overcurrents and coupled to the latch member through an ambient compensator bimetal cantilevered from the latch member. A flexible shunt connected between the helical bimetal and contact arm passes through an extension of the magnetic circuit of the trip motor to generate a magnetic field of sufficient strength to trip the latch member instantaneously in response to a short circuit.
摘要:
The toggle mechanism of a circuit breaker is connected at one end to the pivoted contact arm and at the other end to a pivoted latch lever which is engaged to latch the toggle mechanism by a latch member pivoted for movement in a plane perpendicular to the plane of the toggle mechanism. The latch member serves as an armature for a trip motor energized by a trip circuit responsive to an arc fault and/or a ground fault to unlatch the toggle mechanism and trip the circuit breaker open. The latch member is also tripped by a helical bimetal responsive to persistent overcurrents and coupled to the latch member through an ambient compensator bimetal cantilevered from the latch member. A flexible shunt connected between the helical bimetal and contact arm passes through an extension of the magnetic circuit of the trip motor to generate a magnetic field of sufficient strength to trip the latch member instantaneously in response to a short circuit.
摘要:
An aircraft circuit breaker includes a housing; separable contacts mounted in the housing; a latchable operating mechanism including a latch member which when unlatched opens the separable contacts; and an overcurrent assembly responsive to selected conditions of current flowing through the separable contacts for unlatching the latch member to trip the separable contacts open. A movable and illuminable arc fault indicator has a first ring portion and second leg portions internal to the housing. An arc fault actuator which when energized moves one of the second leg portions. An arc fault current assembly responds to selected arc fault conditions of current flowing through the separable contacts to energize the arc fault actuator to move the second leg portions internal to the housing and the first ring portion external to the housing. The arc fault current assembly includes a light for illuminating the first ring portion.
摘要:
Electrical switching apparatus such as a power circuit breaker, network protector or switch has a self-supporting operating mechanism module including a cage formed by a pair of side plates rigidly clamped in spaced relation by spacers. The cage supports all of the operating mechanism components including a helical compression close spring mounted fully between the side plates and coupled to a cam member through a rocker in a manner which maintains the forces longitudinal to the spring. The cam member has a charging cam with a charge profile for compressing the close spring and a close profile through which the spring drives the cam member to effect a controlled release of stored energy to close the contacts of the apparatus. The cam shaft is captured between bushings seated in non-circular openings in the side plates thereby eliminating the need for any fasteners. Likewise, other parts mounted between the side plates and joined by pins having enlarged heads retained by the side plates do not need retainers. Various shafts extending between the side plates have reduced diameter ends of progressive lengths for successive insertion in one side plate to aid in assembly of the operating mechanism.
摘要:
A circuit breaker includes a housing; separable contacts mounted in the housing; and an operating mechanism for opening and closing the separable contacts. An overcurrent assembly is responsive to selected conditions of current flowing through the separable contacts and actuates the operating mechanism to trip open the separable contacts. A bonnet forms a U-shape which surrounds the separable contacts and which cools and splits an arc when the operating mechanism trips open the separable contacts. A first bonnet piece forms a first leg of the bonnet, and a second bonnet piece forms a second leg and a base of the bonnet.
摘要:
A vacuum arc interrupter that includes a vacuum chamber assembly having a first conductor and a pressure chamber assembly having a second metal conductor, with an opening, and a bullet assembly. The first conductor is coupled to a power line and the second conductor is coupled to a ground. The bullet assembly has a metal lance structured to engage the opening. The lance is shaped to create an arc when engaging the opening so that the second conductor and the lance are welded together.
摘要:
A circuit breaker includes a housing; separable contacts mounted in the housing; and an operating mechanism for opening and closing the separable contacts. An overcurrent assembly is responsive to selected conditions of current flowing through the separable contacts and actuates the operating mechanism to trip open the separable contacts. A bonnet forms a U-shape which surrounds the separable contacts and which cools and splits an arc when the operating mechanism trips open the separable contacts. A first bonnet piece forms a first leg of the bonnet, and a second bonnet piece forms a second leg and a base of the bonnet.
摘要:
A circuit breaker includes a housing; separable contacts mounted in the housing; a latchable operating mechanism including a latch lever which when released opens the separable contacts; and an overcurrent assembly responsive to selected conditions of current flowing through the separable contacts for releasing the latch lever to trip the separable contacts open. The circuit breaker also includes an arc fault indicator; an arc fault trip actuator which when energized moves a first indicator latch for actuating the arc fault indicator and a second latch for releasing the latch lever to trip the separable contacts open; and an arc fault current assembly responsive to selected arc fault conditions of current flowing through the separable contacts for energizing the arc fault trip actuator to actuate the arc fault indicator and to trip the separable contacts open.