Siemens Aktiengesellschaft

Marco Schönenberg

Dirk Hertz

Stefan Zitzler

Johann Seitz

Florian Ringer

Helene Steuer

Methods for controlling a voltage present at an electric fan during a startup of the fan are disclosed herein. The fan serves to generate a flow of air for cooling a device. The method includes applying an output voltage of a power supply, which serves to supply voltage to the device, to the fan; and switching on and switching off the output voltage of the power supply applied to the fan by a switch pulse-width-modulated-controlled by a control unit so that the Root Mean Square value of the current flowing through the fan is less than a startup current of the fan.

Methods for controlling a voltage present at an electric fan

An embodiment relates to a switchgear for a single-phase motor and a three-phase motor, the switchgear including a processing unit and a first, second and third current path, the first and third current path each including a current transformer. The processing unit is adapted to detect the current Iof the first current path and the current Iof the third current path. To provide a cost-effective switchgear for a one-phase motor and a three-phase motor which is adapted to identify the failure of every single phase in the three-phase operation and a phase failure in the one-phase operation, the processing unit is designed such as to detect the currents I, Iof the first and third current path and to determine, based on the phase shift between the detected currents I, Iof the first and third current path in which operating mode the switchgear is operated.

Switchgear for a single-phase motor and a three-phase motor

An embodiment of the invention relates to a switchgear which includes a control unit, a supply connection and a first current path. The first current path includes a first electromechanical switch and, connected in series to the first switch, a parallel connection of a second electromechanical switch to a semiconductor switch. The switchgear includes an energy accumulator and a measuring device. A control unit is capable of monitoring energy supply coming in through the supply connection. If the energy supply through the supply connection reaches a critical range, the control unit controls the output of the switching signals via the energy of the energy accumulator such that: in a first step, the semiconductor switch is switched to be electrically conducting and the second switch is then opened, and in a second step, the semiconductor switch is switched to be electrically non-conducting and the second switch is then opened.

Switchgear for controlling the energy supply of an electric motor connected thereto

A method is disclosed for determining a phase failure in an electrical device for driving or monitoring a three-phase AC motor, wherein the electrical device comprises a first, a second and a third line. In order to detect a phase failure in a line in the three-phase electrical device, in particular in a soft starter, the phase failure in the third line is determined by analysing the first and second lines, wherein the analysis includes: determining a value which characterizes a phase shift between a current in the first and second lines, and outputting a signal if the value which has been determined is in a range of values which characterizes a phase failure in the third line.

Growing community of inventors

Kuemmersbruck, Germany

Marco Schönenberg