A device for cancellation of parasitic voltage on the neutral line and for adjusting phase-to-neutral voltage at the remote end of a long power line comprises an autotransformer and at least two single-port-to-multi-port controllable selectors and a controller. The controller is adapted to enable educated selection of taps of the autotransformer by the controllable single-port-to-multi-port controllable selectors, for setting the phase-to-neutral output voltage to nominal voltage and for canceling the parasitic neutral-to-ground voltage.

A load control apparatus (1) for controlling a power supply to an electrical load connected to an output terminal (3) of the load control apparatus (1) comprising: an overcurrent protection circuit (1A) having a power switch (5) through which the electrical load receives an electrical load current (I.sub.L) and having a sensor component (4) connected in series with the power switch (5) and adapted to generate directly a voltage drop (ΔU.sub.4) corresponding to the current rise speed of the electrical load current (I.sub.L) flowing from an input terminal (2) of the load control apparatus (1) via the sensor component (4) and the power switch (5) to the output terminal (3) and having a driver circuit (6) adapted to detect an occurring overcurrent depending on the voltage drop (ΔU.sub.4) generated by the sensor component (4) and/or a voltage drop (ΔU.sub.5) along the power switch (5) and adapted to switch off said power switch (5) upon detection of an overcurrent within a switch-off period of less than one millisecond; and/or comprising a power supply control circuit (1C) having a sensor component (9) adapted to measure at the input terminal (2) a supply voltage notified to a control unit (8) of the load control apparatus (1) adapted to control an electrical power supplied to the electrical load.

A load protection apparatus for protecting an electrical load connected to an output terminal (3) of the load protection apparatus (1) against overcurrent, said apparatus (1) comprising: an overcurrent protection circuit (1A) having a power switch (5) through which the electrical load receives an electrical load current (I.sub.L) via the output terminal (3) and having a sensor component (4) connected in series with the power switch (5) and adapted to generate directly a voltage drop (ΔU.sub.4) corresponding to the current rise speed of the electrical load current (I.sub.L) flowing from an input terminal (2) of the load control apparatus (1) via the sensor component (4) and the power switch (5) to the output terminal (3) and having a driver circuit (6) adapted to detect an occurring overcurrent depending on the voltage drop (ΔU.sub.4) generated by the sensor component (4) and depending on a voltage drop (ΔU.sub.5) along the power switch (5) adapted to switch off said power switch (5) upon detection of an overcurrent within a switch-off period.

A method for determining a function of a capacitor of a passive filter circuit, which partially reduces line-conducted interference of an electrical device electrically coupled to a power supply system via the passive filter circuit. The passive filter circuit comprises the capacitor having a predefined capacitance value and a choke having a predefined inductance value. An electric capacitor voltage on the capacitor is detected. A connection voltage of the electrical device is detected. Spectral components are determined for the capacitor voltage and the connection voltage. The function of the capacitor is determined by analysing the spectral components in consideration of the inductance value of the choke by a statistical processing operation.

A device for grounding an overhead line of a segment of rail track including a first electrical conductor configured for connecting electrically to the overhead line of the segment of rail track, a second electrical conductor configured for connecting electrically to ground and/or a return line of the segment of rail track, a switch configured to enable and disable a connection between the first and second electrical conductors, control means configured to activate and deactivate the switch and communication means configured for wireless communication with a remote communication device, for receiving a control signal from the remote communication device and for accordingly actuating the control means for activating and deactivating the switch, or for blocking the switch, wherein the communication means are configured for communication over a public telecommunication network.

A solid-state circuit protector includes a first power semiconductor device having an ON resistance that increases with increasing temperature and a second power semiconductor device connected in parallel with the first power semiconductor device having an ON resistance that decreases with increasing temperature. During times when abnormally high currents are flowing through the solid-state circuit protector, the second power semiconductor is switched ON so that some or all of the current is diverted through it, thus protecting the first power semiconductor device from being damaged due to overheating. The first power semiconductor device is either switched OFF, allowing it to cool in anticipation of a lighter load, or is configured to remain ON so that it shares the burden of carrying the high current with the parallel-connected second power semiconductor device yet operates cooler and at a lower ON resistance since it is not required to pass the full current.

An overcurrent protection apparatus that protects, from overcurrent, a load circuit including an electric load and wiring electrically connected with each other is provided. The overcurrent protection apparatus includes: a semiconductor switching element that is configured to control energization to the load circuit; and a breaker that stops the semiconductor switching element upon detection of abnormality of overheat or overcurrent at the semiconductor switching element, the breaker having a latch operation mode of continuously stopping the semiconductor switching element even upon cancellation of abnormality detection, and a retry operation mode of canceling stoppage of the semiconductor switching element upon the cancellation of the abnormality detection. The breaker is configured to initially operate in the latch operation mode upon the abnormality detection, and then be switched to the retry operation mode after satisfaction of a predetermined condition.

An adapter that provides a remote control capability for a light switch is mounted on a support structure (e.g. a wall), and includes a base plate which is also mounted on the support structure to surround the ON/OFF mechanism of the light switch. A cover which can be selectively attached to the base plate establishes an enclosed space between the base plate and the cover. A connector is mounted on the adapter in the enclosed space to interact mechanically with the ON/OFF mechanism of the light switch. The connector also interacts electronically with an activator that is positioned at a remote location. In operation, the connector at the adapter is responsive to an input signal from the remotely located activator that will operate the ON/OFF mechanism. Alternatively, the ON/OFF mechanism can be disconnected from the activator and operated manually.

A downhole-type system includes a rotatable rotor, a magnetic thrust bearing coupled to the rotor, and a mechanical thrust bearing coupled to the rotor. The magnetic thrust bearing is configured to support a first portion of an axial load of the rotor during rotor rotation, and the mechanical thrust bearing is configured to support a second portion of the axial load of the rotor during rotor rotation.

An adapter that provides a remote control capability for a light switch is mounted on a support structure (e.g. a wall), and includes a base plate which is also mounted on the support structure to surround the ON/OFF mechanism of the light switch. A cover which can be selectively attached to the base plate establishes an enclosed space between the base plate and the cover. A connector is mounted on the adapter in the enclosed space to interact mechanically with the ON/OFF mechanism of the light switch. The connector also interacts electronically with an activator that is positioned at a remote location. In operation, the connector at the adapter is responsive to an input signal from the remotely located activator that will operate the ON/OFF mechanism. Alternatively, the ON/OFF mechanism can be disconnected from the activator and operated manually.