A motor control system includes a main control unit, a power supply unit, and a driving unit. The main control unit obtains sampling data of a motor and a power supply signal from the driving unit, generates a motor control signal according to the sampling data, and outputs a safety enable signal when determining that motor drive is abnormal according to the sampling data or when determining that power supply to the driving unit is abnormal according to the power supply signal. The power supply unit supplies power to the main control unit, monitors a state of the main control unit, and outputs a safety cut-off signal when the power supply unit or the main control unit is abnormal. The driving unit drives the motor according to the motor control signal, and switches to a safe path when receiving any one of the safety enable or safety cut-off signal.

A protection device for an electric DC grid includes a first protection circuit part including a series circuit consisting of a first discharge resistor and a first protection switch between a positive potential line and a reference potential line and a second protection circuit part including a series circuit consisting of a second discharge resistor and a second protection switch between a negative potential line and the reference potential line. The first and second protection switches can be actuated to close if a first and/or second voltage measuring device ascertains that a specified voltage value has been undershot and/or exceeded or the first and/or second protection switch can be actuated to close in an event of a fault current measured by a fault-current measuring device.

A method for monitoring a protective device, which has a series circuit of a multiplicity of thyristors. The protective device has a series circuit of N>1 thyristors. The series circuit is connected in a parallel circuit with an electrical device to be protected. A snubber branch is connected in parallel with each thyristor. For the purpose of testing a firing capacity, n<N thyristors in a first thyristor group are fired when a positive voltage is present across the series circuit and a negative snubber current is flowing through the snubber branches of the thyristors in the first thyristor group.

Electrical power distribution systems with a bypass unit that electrically engages one of two alternate units for powering a load while electrically isolating the other using a power transfer switch with first and second contactors and mechanical and electrical interlocks to allow a technician to access one of the alternate units when de-energized and in position while the other of the alternate units is energized and powering the load.

The present invention relates to a residual current circuit breaker, RCCB, (100) for an electrical circuit (300). The RCCB comprises a first switching device (106) and a second switching device (140) coupled in series with each other between the power supply (302) and the load (304). The first switching device (106) is configured to switch into an OFF mode, in which no current is fed to the load (304), upon detecting that a value of a current i fed to the load (304) is larger than a switching current is of the first switching device (106). The second switching device (140) is configured to switch into an ON mode, in which the load (304) is short cut, upon detecting a leakage of the current i fed to the load (304). Thereby, a novel RCCB architecture is provided. When a current leakage is detected a short cut is introduced which means that the voltage will be zero over the load and no person will be harmed by the current in the circuit. Flowever, when the load is short cut there will be a current rush in the circuit which will trigger the first switching device to break the circuit and no current will thereafter flow in the circuit. The invention also relates to a circuit comprising such a residual current circuit breaker and a corresponding method.

A crowbar module includes first and second electrical terminals, a module housing, and first and second crowbar units. The first crowbar unit is disposed in the module housing and includes a first thyristor electrically connected between the first and second electrical terminals. The second crowbar unit is disposed in the module housing and includes a second thyristor electrically connected between the first and second electrical terminals in electrical parallel with the first crowbar unit.

A protection device, for operating an electric machine at a converter, comprises a first and second conductor of a DC link, a switching device having a first and second switch, a link capacitor, a load resistor as a precharge and braking resistor, a semiconductor switch and an electrical fuse for protecting the load resistor. The electrical fuse and the first switch are connected in series to the first conductor and to a first resistor connection of the load resistor and to a first power connection of the semiconductor switch. The second switch is connected to the electrical conductor and to a first capacitor connection of the link capacitor and to a second resistor connection of the load resistor. The semiconductor switch is connected by a second power connection to the second conductor and the link capacitor is connected by a second capacitor connection to the second conductor.

A disclosed electric fence system includes an electric fence; an energizer for generating a plurality of electric pulses applied to the electric fence; a detection circuit for monitoring a voltage of the electric fence; and a grounding device for grounding the electric fence when the electric fence is off. The grounding device is connected to the electric fence, the energizer, the detection circuit, and the ground.

A forced discharge test apparatus includes a heating circuit; a discharge circuit; a temperature sensor; and a controller. When the controller receives a test command indicating a test resistance and a test temperature, the controller outputs a first control signal to the heating circuit to increase the temperature of a battery cell. The controller outputs a second control signal to the discharge circuit to discharge the battery cell when the temperature of the battery cell reaches the set test temperature. The controller determines that the test temperature is valid with respect to the test resistance when the temperature of the battery cell is equal to or lower than the upper temperature limit at a time point at which a predetermined heating time has passed from a time point when the first control signal is outputted.

A device includes a rectifier connected to a receiver coil, a first overvoltage protection apparatus connected between inputs of the rectifier and ground, and a second overvoltage protection apparatus connected between an output of the rectifier and ground, wherein in an overvoltage event, the first overvoltage protection apparatus and the second overvoltage protection apparatus are controlled based upon a comparison between a switching frequency of the device and a predetermine frequency threshold.