A circuit protection apparatus includes separable contacts, an operating mechanism, an electronic trip unit storing a plurality of trip parameter combinations, wherein each of the trip parameter combinations specifies a certain value for each of a plurality of individual trip parameters, and a multi-position selector moveable among a plurality of predetermined positions and configured to enable selection of one of the predetermined positions. Each of the positions corresponds to a respective one of the trip parameter combinations, wherein the electronic trip unit is structured to, responsive to a chosen one of the plurality of predetermined positions being selected by the multi-position selector, cause the one of the trip parameter combinations corresponding to the chosen one of the plurality of predetermined positions to be used by the electronic trip unit to determine whether to cause the operating mechanism to trip open the separable contacts.

Disclosed embodiments include an instant trip mechanism for a molded case circuit breaker. In some embodiments, the mechanism includes an adjustment dial to set a current for an instant trip operation; an instant bar provided with an upper portion contactable with the adjustment dial, a shaft portion serving as a rotation shaft, and a lower extending portion downwardly extending from the shaft portion; an electromagnet unit to generate a magnetic attraction force that is proportional to an amount of current flowing on the circuit; an armature rotatable with a lower end portion supported by a shaft, and attracted toward the electromagnet unit by the magnetic attraction force; and a spring for applying to the armature a load varying in a direction of the armature getting away from the electromagnet unit.

Disclosed embodiments include an instant trip mechanism for a molded case circuit breaker. In some embodiments, the mechanism includes an adjustment dial to set a current for an instant trip operation; an instant bar provided with an upper portion contactable with the adjustment dial, a shaft portion serving as a rotation shaft, and a lower extending portion downwardly extending from the shaft portion; an electromagnet unit to generate a magnetic attraction force that is proportional to an amount of current flowing on the circuit; an armature rotatable with a lower end portion supported by a shaft, and attracted toward the electromagnet unit by the magnetic attraction force; and a spring for applying to the armature a load varying in a direction of the armature getting away from the electromagnet unit.

Circuit breakers with a housing with a line side and a load side and an electronically controlled lock-out lock member coupled to the housing configured to electronically controllably travel between a first position and a second position. In the second position, the lock member is in a lock-out position and prevents the handle from moving to an ON position associated with electrical current conduction and in the first position the lock member is translated to a position that allows the handle to move to the ON position.

Circuit breakers with a housing with a line side and a load side and an electronically controlled lock-out lock member coupled to the housing configured to electronically controllably travel between a first position and a second position. In the second position, the lock member is in a lock-out position and prevents the handle from moving to an ON position associated with electrical current conduction and in the first position the lock member is translated to a position that allows the handle to move to the ON position.

A design of a protection relay, and interface with an operator of a protection relay, are disclosed. The protection relay can include a base relay for measurement of line current and for generation of a trip signal, a base Human Machine Interface (HMI) for user specifying of a base setting of an operating parameter of the protection relay, and an optionally active Human Machine Interface (HMI) unit having a processing unit to manage plural activities with controlled power consumption.

An adjustable thermal trip mechanism for a circuit breaker is provided which can improve the reliability of over-current tripping by minimizing an influence upon thermal tripping even if an assembly error such as skewing or twisting occurs during assembly of bimetallic strips. The adjustable thermal trip mechanism for the circuit breaker comprises: a crossbar that is rotatable and has at least one power receiving portion for receiving rotary power; a bimetallic strip that can bend towards the power receiving portion when an over current occurs on the circuit; and an adjustment screw installed to face the power receiving portion, wherein the power receiving portion comprises a plurality of planar portions which are at different distances from the adjustment screw.

An adjustable thermal trip mechanism for a circuit breaker is provided which can improve the reliability of over-current tripping by minimizing an influence upon thermal tripping even if an assembly error such as skewing or twisting occurs during assembly of bimetallic strips. The adjustable thermal trip mechanism for the circuit breaker comprises: a crossbar that is rotatable and has at least one power receiving portion for receiving rotary power; a bimetallic strip that can bend towards the power receiving portion when an over current occurs on the circuit; and an adjustment screw installed to face the power receiving portion, wherein the power receiving portion comprises a plurality of planar portions which are at different distances from the adjustment screw.

Circuit breakers with a housing with a line side and a load side and an electronically controlled lock-out lock member coupled to the housing configured to electronically controllably travel between a first position and a second position. In the second position, the lock member is in a lock-out position and prevents the handle from moving to an ON position associated with electrical current conduction and in the first position the lock member is translated to a position that allows the handle to move to the ON position.

Circuit breakers with a housing with a line side and a load side and an electronically controlled lock-out lock member coupled to the housing configured to electronically controllably travel between a first position and a second position. In the second position, the lock member is in a lock-out position and prevents the handle from moving to an ON position associated with electrical current conduction and in the first position the lock member is translated to a position that allows the handle to move to the ON position.