Siemens Aktiengesellschaft

Henry Franke

Stefan Haebel

Rainer Huentemeier

Bernd Schwinn

Wolfgang Fruth

Holger Hochgraef

Michael Strassburger

Ilka Redmann

Ulrich Baumgaertl

Wolfgang Roehl

Jeffery C Mizener

An electrical switch for switching an electric current is disclosed. The electrical switch includes an electronic trip unit, embodied in a bipartite fashion. A first part of the trip unit is fixedly connected to the electrical switch and includes protection functions of the electrical switch. A second part of the trip unit is embodied mountably and detachably on the electrical switch and defines the protection functions enabled for the customer.

Electrical switch

A circuit breaker is disclosed for interrupting an electrical circuit when current limit values are exceeded. The circuit-breaker includes a current sensor for determining the electrical current flow and a control device. When current limit values are exceeded, the electrical circuit is interrupted. A first current limit value, when exceeded, results in an immediate interruption and a second current limit value, when exceeded, results in a time-delayed interruption, such that the second interruption time reduces as the current increases. Only one control element is included for setting a current limit value. The element defining the second current limit value is included for the time-delayed interruption of the electrical circuit. The other parameters are either set in a fixed manner and/or are related to the settable second current limit value.

Configurable circuit-breaker

An electrical switch is disclosed for switching an electric current between a feed and an outgoer. The electrical switch can be mounted in a switchgear assembly and as a result electrical contact can be made with the electrical switch by a feed and an outgoer of the switchgear assembly. In one embodiment, the electrical switch includes an internal voltage tap for supplying power to a switch-internal electronics system and a changeover switch. The changeover switch adjusts the electrical connection between the feed or the outgoer and the internal voltage tap.

A circuit breaker includes a tripping unit for interrupting an electrical circuit, and at least one current sensor for determining the electrical current flowing through the circuit breaker, connected to a control unit and configured such that the determined current is compared with current/period limit values. If a current/period limit value is exceeded, the tripping unit interrupts the electrical circuit. The current/period limit values include an adjustable first current limit value, present for a first period for an interruption; an adjustable second period, during which a second current limit value must be present to effect an interruption; and a range between the first current limit value and the second current limit value, the period decreasing with increasing current limit values in order to effect an interruption. The second current limit value can be adjusted at the circuit breaker.

Circuit breaker

A circuit breaker is disclosed, including a series circuit including a measuring unit for determining the electrical current or/and voltage of the electrical circuit, an exchangeable trip unit for determining when current limit values are exceeded, and a switching unit for interrupting the electrical circuit if current limit values are exceeded. A switch characteristic module is connected to the trip unit and stores characteristic data relating to the circuit breaker. If a trip unit used is at least exchanged for a new trip unit, the characteristic data are transmitted to the new trip unit. Data specific to the trip unit are transmitted from the trip unit and are stored in the further memory area of the switch characteristic module. If a new trip unit is used, the characteristic data and the data specific to the trip unit are transmitted to the new trip unit.

Circuit breaker for an electrical circuit

A circuit breaker is disclosed for an electrical circuit. The circuit breaker includes a tripping unit; at least one current sensor; and an input for a signal, at which a blocking signal for a circuit breaker arranged upstream on the energy sink side, can be received. The tripping unit; at least one current sensor; and an input are all connected to a control unit. A connectable blocking function is provided. The ascertained current is compared with a first current limit value, the exceeding of which requires this first current value to be present for a first period of time in order to prompt interruption of the electrical circuit; and is compared with a second current limit value. Different periods of time need to be present to prompt interruption when the blocking function is disengaged or engaged.

The method for the automatic adjustment of a protective device includes determining an integral of the square of a motor current over time on the basis of a time motor current profile of an asynchronous motor on a load, after switching on and reversing and deriving a tripping time of the overcurrent release on the basis of the determined integral, the integral, which corresponds to a heating of the asynchronous motor, being related to a multiple of the square of the rated current, and the motor current profile including at least the starting current, the transient and the selected motor rated current.

Method for the automatic adjustment of a protective device having an excess-current release, particularly a low-voltage circuit breaker

A protective device is disclosed having a circuit breaker for an electrical connection between a transformer and a load, wherein an overcurrent device is arranged between the transformer and the load. The overcurrent device has first magnetoelectric transducers arranged at each phase conductor and the neutral conductor, wherein the overcurrent device uses the transducer currents to in each case establish the presence of a first ground-fault current, and wherein the circuit breaker has a switching device, which interrupts at least the phase conductors between the transformer and the load in the event of the presence of a first ground-fault current (unrestricted earth fault). In order to also be able to determine the ground fault current between the transformer and the circuit breaker, at least one embodiment of the invention proposes providing in each case second magnetoelectric transducers at each phase conductor, the neutral conductor and a star-point conductor which is connected to the star point, using the transducer currents of the second transducer in each case to determine the presence of a second ground-fault current (restricted earth fault), and forming a signal for disconnecting the transformer in the event of the presence of a second ground-fault current.

Protective device having a circuit breaker, in particular a low-voltage circuit breaker

The circuit contains a primary coil on the core () of a magnetic circuit with an air gap and switchable into a line carrying the measurement current. A secondary compensation coil (), with an order higher winding count and mounted on the core, is connected to the output of a controllable compensation current source (). The output of a Hall element () in the air gap is connected to the control input of the compensation source. A further coil () on the core is connected to an additional controllable current generator () whose control input () is driven by a measurement device () for the compensation current via a control and evaluation circuit (). USE/ADVANTAGE&#x2014;Measuring a.c. and d.c. Can be produced at low cost and all drift occurring during measurement can be compensated.

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Berlin, Germany

Henry Franke