A direct-current (DC) air circuit breaker for opening and closing a circuit according to various embodiments includes a circuit unit having a main circuit, a detecting unit having a detection circuit for detecting a fault current in the main circuit, and a circuit operating device configured to allow connection or isolation between the main circuit and the detection circuit.

The invention disclosed is a knife blade switch 2 having copper jaws 10 and a copper blade 4 with a steel end-plate 6 fastened to the free end of the blade, the steel end-plate having a higher resistivity than the resistivity of the copper blade and copper jaws. As the copper blade is withdrawn from the copper jaws, the steel end-plate of the blade remains in contact with a higher resistivity steel jaw-spring mounted on and electrically connected to the copper jaws. The connection of the steel end-plate 6 of the blade with the steel jaw-spring 12 imposes a greater resistance path for the current flowing through the switch than through the copper blade 4 and copper jaws 10, so that an arc formed at the plate and jaw-spring has a diminished current, over what would otherwise occur with a copper blade and jaws, when the contact separation occurs.

The invention disclosed is a knife blade switch 2 having copper jaws 10 and a copper blade 4 with a steel end-plate 6 fastened to the free end of the blade, the steel end-plate having a higher resistivity than the resistivity of the copper blade and copper jaws. As the copper blade is withdrawn from the copper jaws, the steel end-plate of the blade remains in contact with a higher resistivity steel jaw-spring mounted on and electrically connected to the copper jaws. The connection of the steel end-plate 6 of the blade with the steel jaw-spring 12 imposes a greater resistance path for the current flowing through the switch than through the copper blade 4 and copper jaws 10, so that an arc formed at the plate and jaw-spring has a diminished current, over what would otherwise occur with a copper blade and jaws, when the contact separation occurs.

A circuit breaker having a circuit operating device according to one embodiment of the present invention includes a circuit unit having a main circuit, a detecting unit having a detection circuit for detecting a fault current in the main circuit, and a circuit operating device configured to allow connection or isolation between the main circuit and the detection circuit, wherein the circuit operating device includes a first fixed unit and a second fixed unit connected to the main circuit and the detection circuit, respectively, and arranged in parallel to each other, and a moving unit rotatably coupled between the first fixed unit and the second fixed unit to connect or isolate the main circuit and the detection circuit to or from each other.

A test switch signal analyzer comprising: an analyzer hub operably couplable to a test switch base that includes test switch conductors; signal probe(s) couplable to the analyzer hub and to the plurality of test switch conductors when the analyzer hub is coupled to the test switch base, a signal processing unit coupled to the analyzer hub; the signal processing unit, the analyzer hub, and at least a portion of the at least one signal probe being positionable within a test switch cover that mates with the test switch base when the signal probe is coupled to the test switch conductor(s) and the test switch cover is secured to the test switch base.

A safety device is provided for use in conjunction with a knife switch disposed in a switch well. The safety device comprises an elongate base member having a head end and an insertion portion extending distally away therefrom. The insertion portion is configured for at least partial insertion into the switch well between the knife switch and an internal wall of the switch well when the knife switch is in its open configuration. The device further comprises a slot formed in at least a portion of the insertion portion of the base member. The slot is sized and positioned to receive at least a portion of the blade when the knife switch is in its open configuration and the insertion portion is inserted into the switch well between the knife switch and the internal wall.

A safety device is provided for use in conjunction with a knife switch disposed in a switch well. The safety device comprises an elongate base member having a head end and an insertion portion extending distally away therefrom. The insertion portion is configured for at least partial insertion into the switch well between the knife switch and an internal wall of the switch well when the knife switch is in its open configuration. The device further comprises a slot formed in at least a portion of the insertion portion of the base member. The slot is sized and positioned to receive at least a portion of the blade when the knife switch is in its open configuration and the insertion portion is inserted into the switch well between the knife switch and the internal wall.

A test switch signal analyzer comprising: an analyzer hub operably couplable to a test switch base that includes test switch conductors; signal probe(s) couplable to the analyzer hub and to the plurality of test switch conductors when the analyzer hub is coupled to the test switch base, a signal processing unit coupled to the analyzer hub; the signal processing unit, the analyzer hub, and at least a portion of the at least one signal probe being positionable within a test switch cover that mates with the test switch base when the signal probe is coupled to the test switch conductor(s) and the test switch cover is secured to the test switch base.

The invention disclosed is a knife blade switch 2 having copper jaws 10 and a copper blade 4 with a steel end-plate 6 fastened to the free end of the blade, the steel end-plate having a higher resistivity than the resistivity of the copper blade and copper jaws. As the copper blade is withdrawn from the copper jaws, the steel end-plate of the blade remains in contact with a higher resistivity steel jaw-spring mounted on and electrically connected to the copper jaws. The connection of the steel end-plate 6 of the blade with the steel jaw-spring 12 imposes a greater resistance path for the current flowing through the switch than through the copper blade 4 and copper jaws 10, so that an arc formed at the plate and jaw-spring has a diminished current, over what would otherwise occur with a copper blade and jaws, when the contact separation occurs.

An input device comprises a depressible element with two switches including a first switch configured to generate a first signal when the depressible element is depressed by a threshold distance and a second switch configured to generate a second signal indicating when the depressible element is depressed by the threshold distance and the second switch is in an active state. One or more processors may be configured to receive the first signal from the first switch; configure the second switch to change from an inactive state to an active state in response to receiving the first signal; receive the second signal from the second switch in the active state; determine whether the second signal indicates that the depressible element is depressed by the threshold distance; and generate event data confirming that the depressible element is depressed by the threshold distance in response to receiving the second signal.