Protection of an electric motor drive controller from a transient voltage is described herein. The transient voltage is provided by an alternating current (AC) power line that includes a line conductor, a neutral conductor, and a ground conductor. The transient voltage protection system includes a first stage protection device coupled to an input of a rectifier of the motor drive controller. The first stage protection device is configured to suppress the transient voltage to prevent damage to the motor drive controller. The transient voltage protection system also includes a second stage protection device coupled between the rectifier and an inverter of the motor drive controller. The second stage protection device is configured to further suppress the transient voltage to prevent damage to the inverter.

A motor controller circuit includes an electrical powertrain having a three phase input, a DC link and a three phase output, a controller including a processor and a memory, a first current sensor configured to sense a current at the three phase input, a second current sensor configured to sense a current at the three phase output, and a third sensor configured to sense a current at the DC link, and wherein the memory stores instructions configured to cause the processor to compare an operational model of the powertrain against a mathematical model of the powertrain and to detect a high impedance fault when a deviation between the operational model and the mathematical model exceeds a threshold.

A wireless power transfer system is disclosed. The wireless power transfer system includes a first converting unit configured to convert a first DC voltage of an input power to a first AC voltage. Further, the wireless power transfer system includes a contactless power transfer unit configured to receive the input power having the first AC voltage from the first converting unit and transmit the input power. Also, the wireless power transfer system includes a second converting unit configured to receive the input power from the contactless power transfer unit and convert the first AC voltage of the input power to a second DC voltage. Furthermore, the wireless power transfer system includes a switching unit configured to decouple the second converting unit from the contactless power transfer unit if the second DC voltage across the electric load is greater than a first threshold value.

A protective redundancy circuit is provided for a power tool having an electric motor. The protective redundant subsystem is comprised of: a motor switch coupled in series with the motor; a motor control module that controls the switching operation of the motor switch; and a protective control module that monitors switching operation of the motor switch and disables the power tool when the switching operation of the motor switch fails. In the context of an AC powered tool, the switching operation of the motor switch is correlated to and synchronized to the waveform of the AC input signal. During each cycle or half cycle, the motor control module introduces a delay period before closing the motor switch and the protective control module determines the operational status of the motor switch by measuring the voltage across the motor switch during the delay period.

A voltage transformer includes: a body with primary windings and secondary windings coupled to each other by electromagnetic induction; a measuring device electrically connected to the secondary windings via a first fuse; and a relay having a coil and at least one pole with normally open contacts, the at least one pole being configured to be thrown by an energizing of the coil. The coil is arranged in series with the primary windings. The at least one pole with normally open contacts is arranged between the secondary windings via the first fuse in order to short circuit the first fuse when the at least one pole is thrown.

An electronic switch has a first, a second and a third connection and is configured to disconnect a current flow between the first and the second connection. An energy source is connected between the first and the third connection, and a regenerative load is connected between the second and the third connection. The electronic switch includes a semiconductor switch capable of switching currents of different polarity. A fuse is connected between the first connection and the semiconductor switch. A first short-circuiter is connected between the input of the semiconductor switch and the third connection, and a second short-circuiter is connected between the output of the semiconductor switch and the third connection. The fuse has a current trigger threshold between a permanently permitted current and a maximally permitted current of the semiconductor switch. An electrical network having such electronic switch and a method for operating an electronic switch are disclosed.

An electronic switch has a first semiconductor switch arranged between a first source-side terminal and a first consumer-side terminal first, and a switch embodied as a thyristor and arranged between the first consumer-side terminal and a second source-side terminal. The switch is configured to generate a thermal overload from a short-circuit current produced when the switch closes. The thermal overload causes the first semiconductor switch to irreversibly transition into an open state due to a modification inside the first semiconductor switch caused by the thermal overload. This improves the switching behavior of the electronic switch in the event of a fault. Furthermore, an electrical network with at least one electronic switch connected to an energy source and a method for operating such an electronic switch or such an electrical network is also described.

A short circuit current detection device for a medium voltage or high voltage switchgear includes: a reed contact; and a holder for holding the reed contact, the holder being mountable with a defined orientation to a conductor of the switchgear. At a location where the holder is mounted, the conductor has a longitudinal axis. The conductor enables a current to flow through the conductor in a direction of the longitudinal axis. The holder positions the reed contact with respect to the longitudinal axis such that when a magnitude of the current flow through the conductor exceeds a threshold current value the reed contact closes.

A fault-arc identification unit for an electric circuit, includes at least one voltage sensor, for the periodic determination of electric voltage values; and at least one current sensor, for the periodic determination of electric current variables of the circuit. Both sensors are connected to an evaluation unit, designed such that: electric voltage values are fed to a first fault-arc identification function which carries out a first fault-arc identification based upon a signal profile of the voltage, and emits a first fault-arc identification signal upon a first threshold value being exceeded; electric voltage values and current variables are fed to a second fault-arc identification function which carries out a second fault-arc identification based upon the voltage values and current variables, and emits a second fault-arc identification signal upon a second threshold value being exceeded. The fault-arc identification signals are fed to an inclusive disjunction function, to emit a fault-arc identification signal.

A digital device is provided. The digital device uses three states, including a ground (GND) state, a voltage (VDD) state, and a FLOAT state. On designing a chip, two storage units and a pad circuit are set inside; the pad circuit comprises a current limiter and two switches; and less ports contained are required than the conventional. That is, one port obtains three states. As comparing to the conventional having only two states, the present invention uses the port connected with two storage units in the pad circuit for obtaining the three states; a circuit featuring “pull up” and “pull down” is used to identify the state of connection of the port; and the port determines a plurality of definitions through the three states of GND, VDD and FLOAT. Thus, a pad is saved for reducing the space and cost of the chip.