A transformer assembly including a transformer that is part of an underground residential power distribution circuit and that provides fault isolation and restoration. The transformer assembly includes an enclosure enclosing a primary winding and a secondary winding. The transformer assembly also includes first and second switching devices mounted to a panel of the enclosure, where each switching device includes an outer housing, a transformer interface electrically coupled to the primary winding, a connector interface electrically coupled to a first connector and a vacuum interrupter having a fixed contact and a movable contact. The fixed contact is electrically coupled to the connector interface or the transformer interface and the movable terminal is electrically coupled to the other connector interface or the transformer interface.

A method for isolating a fault in an underground power distribution network. The network includes a power line, a plurality of transformers electrically coupled to and positioned along the power line, a first end switch connected to one end of the power line and a second end switch connected to an opposite end of the power line, where each transformer includes an upstream switching device and a downstream switching device, and where source power is provided to both ends of the power line through the first and second end switches and one of the switching devices is a normally open switching device. The method includes detecting overcurrent in the network from the fault, opening certain ones of the switching devices in response thereto, detecting loss of voltage as a result of the open switching devices and opening or closing certain ones of the switching devices to isolate the fault.

A coil actuator for low and medium voltage applications comprising a coil electromagnet provided with a single coil winding and a movable anchor and a power and control unit comprising: a power circuit operatively coupled with said coil electromagnet, said power circuit comprising input terminals, at which said power circuit receives an input voltage; a PWM controller operatively coupled with said power circuit, said PWM controller being adapted to control an input current flowing through said power circuit to obtain and maintain an average operating level selected an excitation current feeding said coil electromagnet. Said PWM controller is adapted to set a plurality of reference values for said input current to control said input current, each reference value for said input current being selected among said plurality of reference values depending on the behavior of said input voltage.

Disconnect switches include a housing, a fixed main contact in the housing, a movable main contact in the housing in cooperating alignment with the fixed main contact, a first actuator coupled to the movable main contact, and a second actuator coupled to the housing. The second actuator is configured to apply a motive force to the housing that is in a direction opposing a motive force applied by the first actuator to the movable main contact.

A circuit breaker includes a vacuum interrupter having a closed position and an open position. The circuit breaker includes a linkage operatively coupled to and extending from the vacuum interrupter and a high-speed actuator operatively connected to the linkage. The high-speed actuator is operable to move the linkage by a repulsion force and cause the vacuum interrupter to move to the open position. The circuit breaker includes a decelerator with an integrated latch assembly operatively coupled to the high-speed actuator. The decelerator decelerates the repulsion force of the high-speed actuator and latches the actuator with the integrated latch assembly to maintain the vacuum interrupter in the open position.

A circuit breaker includes a vacuum interrupter having a closed position and an open position. The circuit breaker includes a linkage operatively coupled to and extending from the vacuum interrupter and a high-speed actuator operatively connected to the linkage. The high-speed actuator is operable to move the linkage by a repulsion force and cause the vacuum interrupter to move to the open position. The circuit breaker includes a decelerator with an integrated latch assembly operatively coupled to the high-speed actuator. The decelerator decelerates the repulsion force of the high-speed actuator and latches the actuator with the integrated latch assembly to maintain the vacuum interrupter in the open position.

A contactor for medium voltage electric systems including: one or more electric poles; for each electric pole, a fixed contact and a corresponding movable contact reversibly movable between a first position, at which the movable contact is decoupled from the fixed contact, and a second position, at which the movable contact is coupled with the fixed contact; an electromagnetic actuator including a magnetic yoke having a fixed yoke member and a movable yoke member, the movable yoke member reversibly movable between a third position corresponding to the first position of the movable contacts, at which the movable yoke member is decoupled from the fixed yoke member, and a fourth position, corresponding to the second position of the movable contacts, at which the movable yoke member is coupled with the fixed yoke member, the electromagnetic actuator including an excitation circuit assembly including an excitation coil wound around the magnetic yoke and electrically connected with an auxiliary electric power supply to be fed with an excitation current to generate an excitation magnetic flux to move the movable yoke member from the third position to the fourth position or to maintain the movable yoke member in the fourth position; an opening springs operatively coupled with the movable yoke member to move the movable yoke member from the fourth position to the third position; a kinematic chain to operatively connect said movable yoke member with said movable contacts. The electromagnetic actuator including camping circuit assembly comprising a damping coil arranged to form a conductive loop adapted to be at least partially enchained with the excitation magnetic flux generated by the excitation current flowing along the excitation coil, when the auxiliary electric power supply provides the excitation current to the excitation coil, so that a secondary current circulates along the damping coil when the excitation magnetic flux is subject to a transient.

A contactor for medium voltage electric systems including: one or more electric poles; for each electric pole, a fixed contact and a corresponding movable contact reversibly movable between a first position, at which the movable contact is decoupled from the fixed contact, and a second position, at which the movable contact is coupled with the fixed contact; an electromagnetic actuator including a magnetic yoke having a fixed yoke member and a movable yoke member, the movable yoke member reversibly movable between a third position corresponding to the first position of the movable contacts, at which the movable yoke member is decoupled from the fixed yoke member, and a fourth position, corresponding to the second position of the movable contacts, at which the movable yoke member is coupled with the fixed yoke member, the electromagnetic actuator including an excitation circuit assembly including an excitation coil wound around the magnetic yoke and electrically connected with an auxiliary electric power supply to be fed with an excitation current to generate an excitation magnetic flux to move the movable yoke member from the third position to the fourth position or to maintain the movable yoke member in the fourth position; an opening springs operatively coupled with the movable yoke member to move the movable yoke member from the fourth position to the third position; a kinematic chain to operatively connect said movable yoke member with said movable contacts. The electromagnetic actuator including camping circuit assembly comprising a damping coil arranged to form a conductive loop adapted to be at least partially enchained with the excitation magnetic flux generated by the excitation current flowing along the excitation coil, when the auxiliary electric power supply provides the excitation current to the excitation coil, so that a secondary current circulates along the damping coil when the excitation magnetic flux is subject to a transient.

A method for closing an actuator in a magnetically actuated switch assembly, where the actuator includes an armature and a winding, and the switch assembly includes a manual actuation device coupled to one end of the armature and a movable terminal in a vacuum interrupter coupled to an opposite end of the armature. The method includes commencing a closing operation of the actuator using the manual actuation device to move the armature towards a closed latch position, detecting that the actuator is being manually closed, and energizing the winding to assist moving the armature to the closed latch position when the armature gets to a predetermined distance from the closed latch position.

A method for closing an actuator in a magnetically actuated switch assembly, where the actuator includes an armature and a winding, and the switch assembly includes a manual actuation device coupled to one end of the armature and a movable terminal in a vacuum interrupter coupled to an opposite end of the armature. The method includes commencing a closing operation of the actuator using the manual actuation device to move the armature towards a closed latch position, detecting that the actuator is being manually closed, and energizing the winding to assist moving the armature to the closed latch position when the armature gets to a predetermined distance from the closed latch position.