Circuits and methods for protecting against over-current conditions of switches are described. Over-current conditions can damage switches and the circuits they connect. Some embodiments of the present application provide a sense switch in parallel with the load switch. The sense switch is smaller than the load switch, and is used to sense an over-current condition of the load switch. The sense switch can remain on even when the load switch is turned off in response to detection of an over-current condition.

Systems, methods, techniques and apparatuses of prognostic testing are disclosed. One exemplary embodiment is a power switch system comprising a power switch; a current sensor; a test current injection circuit comprising: a first direct current (DC) bus rail including an output terminal and a first power supply terminal, a second DC bus rail including an input terminal and a second power supply terminal, a diode coupled to the first DC bus rail, and a leg coupled to the first DC bus rail between the diode and the first power supply terminal and coupled to the second DC bus rail between the input terminal and the second power supply terminal, the leg including a capacitor and a semiconductor device coupled in series; and a controller configured to operate the test current injection circuit to transmit a test current to the current sensor and receive a voltage based on the test current.

A system for monitoring a circuit breaker includes at least one sensor and a processor. The at least one sensor is configured to be located and utilized to obtain at least one time series sensor data of at least one first part an operational circuit breaker. The at least one sensor is configured to provide the at least one time series sensor data of the at least one first part of the operational circuit breaker to the processor. The processor is configured to determine that at least one second part of the operational circuit breaker is operating correctly or has a fault, where the determination includes analysis of the at least one time series sensor data of the at least one first part of the operational circuit breaker by a trained neural network implemented by the processor.

The present invention relates to a self diagnostic apparatus for an electronic device, which includes a vector memory configured to store a test function code for testing a device under test (DUT) equipped with a plurality of cores which perform arithmetic operations, a function test expected value corresponding to a function test according to the test function code, a design for test (DFT) test code, a DFT test expected value corresponding to a DFT test according to the DFT test code, and a non-test function code for a general arithmetic operation or an operation of the DUT; a test data storage configured to store test data including a DFT test code result value which is a result of the DFT test according to the DFT test code, a test function code result value which is a result of the function test according to the test function code, and a non-test function code result value which is a result of the function test according to the non-test function code; and a safety region test controller configured to select one among the test function code, the DFT test code, and the non-test function code to select a test mode, control an environmental variable of a test signal applied to the DUT in response to the selected test mode and test the DUT, compare the function test expected value stored in the vector memory with the test function code result value stored in the test data storage, and compare the DFT test expected value stored in the vector memory with the DFT test code result value stored in the test data storage to output comparison result information.

A high-voltage test terminal includes a first conductor, a second conductor, and a primary insulator disposed between and coupled to the first and second conductors. A blade is movably connected to the second conductor. The blade is electrically and mechanically connected to the first conductor in a first position and electrically isolated and mechanically disconnected from the first conductor in a second position. A guard insulation layer is disposed between the primary insulator and the first conductor.

A system for monitoring electrical contacts for an overhead trolley line may include a wear sensor arranged such that an electrical contact on a vehicle or work machine for contacting the overhead trolley line is continually or periodically in its line of sight. The wear sensor may be configured to capture spatial data defining the surface profile of the electrical contact. The system may also include a data processing module configured to receive the spatial data and identify a defect in the electrical contact based on the spatial data.

A system for monitoring the integrity of a plurality of ground conductors has a plurality of monitors, with a different monitor associated with each ground conductor. Each monitor includes a voltage sensor which monitors voltage on a closed circuit of the monitor. Upon the voltage sensor sensing an unexpected voltage, a transmitter of the monitor issues an “alarm” signal, which may be wireless (e.g., being sent using LoRaWAN protocol). The transmitter may issue other signals, including a periodic “heartbeat” signal to confirm continued operation of the monitor, and a “movement” signal to indicate movement of the monitor. The monitor may be GPS-enabled, in which case each signal may include the GPS coordinates of the monitor. The signals issued by the transmitter may ultimately be analyzed by an operator via a user interface platform, which may simultaneously display information regarding two or more of the plurality of monitors.

Methods for monitoring a circuit breaker include detecting at least one operation of a circuit breaker to obtain at least one vibration signal of the circuit breaker. Each vibration signal is represented as one-dimensional data of a vibration amplitude over time during the operation of the circuit breaker. The vibration signal is transformed to two-dimensional frequency-time data. The transformed frequency-time data is compared with benchmark data characterizing the at least one operation of the circuit breaker. A health condition is determined of the circuit breaker at least in part based on the comparison. Both the frequency component and the time component in the detected test vibration signals are considered in condition determination of the circuit breaker. The condition can be determined with high accuracy.

A method for diagnosing an operating state of a switching device including separable contacts, which are driven by an electromagnetic actuator including a coil connected to an electronic control device, and sensors, which are configured to measure an intensity of a coil current and a coil voltage. The method comprises: a) receiving an order to close via the electronic control device; b) controlling the electromagnetic actuator so that it closes; c) measuring and recording the coil voltage and coil current values; d) calculating and recording values of a magnetic flux through the coil, by integrating the recorded values of the coil current, the coil voltage and resistance and inductance values of the coil; and e) evaluating and recording positions of a core of the electromagnetic actuator according to a data table, which is previously recorded in the electronic control device and which defines a bijective relation between the position of the core, the magnetic flux and the coil current.

A method for diagnosing an operating state of a switching device including separable contacts, which are driven by an electromagnetic actuator including a coil connected to an electronic control device, and sensors that measure a coil voltage and an intensity of a coil current. The method includes: a) receiving an order to open the switching device via the electronic control device; b) controlling the electromagnetic actuator so that it opens; c) measuring and recording the coil voltage and coil current values d) calculating and recording values of a magnetic flux through the coil, by integrating the recorded values of the coil current, the coil voltage and resistance and inductance values of the coil; and e) evaluating and recording positions of a core of the electromagnetic actuator according to a data table, which defines a bijective relation between the position of the core, the magnetic flux and the coil current.