An electric utility distribution system in which power is supplied by a distribution transformer through an electric utility meter including an apparatus for detecting the presence of a back-feed voltage source connected to the load. The apparatus includes a virtual neutral established in the electric utility meter at ground potential and a remote switch that is opened to interrupt electric power flow from the distribution transformer to the load. The apparatus further includes a balanced voltage divider circuit including a connection point established between a pair of series connected resistive elements. In addition, the apparatus includes a detection circuit configured to monitor a voltage signal at the connection point to detect a back-feed voltage source connected between a neutral conductor of the electric utility distribution system and one of a first or second power line at the load.

A changeover apparatus for interruption-free changeover between two energy supply systems includes: at least one first outer conductor section and one second outer conductor section; a first mechanical bypass switch arranged in the first outer conductor section; a first semiconductor circuit arrangement connected in parallel with the first mechanical bypass switch; a first measuring device for recording a first voltage and/or a first mains frequency, which first measuring device is connected to the first outer conductor section; a second mechanical bypass switch arranged in the second outer conductor section; a second semiconductor circuit arrangement connected in parallel with the second mechanical bypass switch; and an electronic control unit for actuating, in a predeterminable manner, the first mechanical bypass switch, the first semiconductor circuit arrangement, the second mechanical bypass switch, and the second semiconductor circuit arrangement. The first measuring device is connected for communication with the electronic control unit.

An automatic transfer switch includes a motor and a drive shaft rotatable by the motor. The automatic transfer switch includes a gear rotatable by the drive shaft. The automatic transfer switch includes a pin attached to, and movable with, the gear. The pin is offset from the central axis of the gear. The automatic transfer switch includes a bracket rotatable around the central axis of the gear and connected to an output shaft. The bracket is rotatable separately from the gear. Upon rotation of the bracket, the output shaft rotates. The bracket has at least a first source position and a second source position and the first and second source positions are different. The automatic transfer switch includes a module connected to the output shaft. The module includes at least one movable electrical contact which moves upon rotation of the output shaft.

According to an embodiment, an automatic transfer switch bypass breaker system can include a first plurality of breakers configured to electrically couple a first input power source or a second input power source to common load bus via an automatic transfer switch in a first state and to electrically isolate the automatic transfer switch from the first and second input power sources and the common load bus in a second state, the first plurality of breakers including at least three breakers, and a second plurality of breakers configured to bypass the automatic transfer switch to electrically couple the first input power source or the second input power source to the common load bus in the second state, the second plurality of breakers includes at least two breakers.

Implementations of the subject matter described herein provide a slowing mechanism for a switching apparatus and a switching apparatus. The slowing mechanism includes: a shaft adapted to be rotatable in response to an operation of an actuator to drive a moving element of the switching apparatus; at least one slowing wheel fixed on the shaft and having a slowing contour; and a movable rocker engaging with the slowing wheel. The slowing wheel is adapted to cause the rocker to move abutting against the slowing contour on the slowing wheel in response to the rotation of the shaft, so as to slow down the rotation of the shaft. The slowing mechanism can slow down the operation of the moving element of a switching apparatus, while not impacting the switching performance and life time of the switching apparatus.

The electrical switch includes three fixed contacts and a rotatable knife contact being connected with a permanent electrical connection to a third one of the fixed contacts and including at least one pair of longitudinal blades. The rotatable knife contact connects in a first switching position only a first one and a third one of the fixed contacts electrically together, and in a second switching position only a second one and a third one of the fixed contacts. The rotatable knife contact connects further in a zero switching position the first, the second and the third fixed contact electrically together.

An ATS bypass switch includes a draw-out ATS switch; a bypass switch; and a processor structured to automatically control both of the draw-out ATS switch and the bypass switch.

A smart circuit breaker includes a communication interface, separable contacts, a processing unit having a memory with a routine stored therein which, when executed by the processing unit causes the processing unit to: sense a power outage in an electrical grid, control a meter to open contacts to disconnect from the electrical grid, sense power restoration to the electrical grid, control contacts corresponding to a secondary power source to open, control the meter to close contacts to reconnect to the electrical grid, sense that a frequency of power from the electrical grid matches a frequency of power from the secondary power source, and control the contacts corresponding to the secondary power source to close.

A method and system are provided for controlling transfer switch operations in a power distribution system. The method and system involve monitoring an electrical parameter of an electrical signal from a first power source associated with supplying power to a load; determining whether the electrical parameter satisfies a parameter threshold; selecting to increment or decrement a count value in accordance with the determination; and responsive to determining that the count value satisfies a first count threshold, initiating a start signal to start operation of a second power source to supply power to the load. The electrical parameter can be voltage or frequency, or other parameter(s) from which a power quality of the electrical signal may be evaluated. The electrical signal can be a single or polyphase electrical signal.

A changeover switch for medium voltage switchgear is provided. The changeover switch includes a first terminal body, a second terminal body, and two elongate pole bodies. The two elongate pole bodies are arranged parallel to each other and rotatably arranged with first ends on opposite sides of, and in direct contact with the first terminal body around a rotation axis. The two elongate pole bodies are rotatable between an open position and a closed position. The second ends of the two elongate pole bodies are positioned in direct contact with opposite sides of the second terminal body. The changeover switch further includes one or more springs arranged between the two elongate pole bodies to urge the two elongate pole bodies towards each other.