Disclosed are a self-power relay and a method for preventing a malfunction thereof. The self-power relay comprises: a self-power generation unit for autonomously generating a driving power by performing conversion into a preconfigured driving power level by using, as a source power, a system power of a transmission/distribution line or power system; and a relay operation unit, for measuring the amount of a system power of a transmission/distribution line or power system, blocking a system power transmitted to a load when a failure occurs, and monitoring a change in a source power of the self-power generation unit in real time, so as to stop a relay operation of the self-power generation unit and a relay operation of the relay operation unit itself when abnormality occurs, wherein a malfunction can be prevented by checking an unstable state of a source current and voltage for generation of a self driving power.

A pantograph remote control circuit for an unmanned metro train includes a startup circuit of an auxiliary inverter emergency start relay, a control circuit of an auxiliary inverter energized relay, and a startup circuit of a pantograph raising relay. A first normally-open contact pair of the pantograph raising relay is serially connected to a pantograph raising electromagnetic valve and then connected to an output terminal of a battery. At the meantime, the bootstrap is remotely controlled by the internal ATC wake-up module when the power supply is fed by the battery, and there is no need for the driver to operate on the spot, thereby saving time for the driver from operations and reducing the potential misoperation of the driver.

A current monitor circuit includes a sense resistor coupled to a direct current (DC) power supply to sense a current signal, an operational amplifier (op-amp) coupled to the sense resistor to sense a voltage developed across the sense resistor, and a low-pass filter coupled to the op-amp and an analog-to-digital converter (ADC). The low-pass filter reduces aliasing due to out-of-band signal content. The current monitor circuit is coupled to the ADC to provide real-time measurements of power supply load current as input to an active power management (APM) firmware.

An under-voltage lockout (UVLO) circuit configured for indicating that an electronic device may be enabled and disabled based on threshold levels of a power supply voltage. The UVLO circuit has a non-differential comparator configured to have a fixed threshold voltage. A voltage divider having a first terminal connected to the power supply voltage and configured to adapt a compare signal applied to the non-differential comparator to be proportional the power supply voltage such that a desired threshold voltage for the power supply voltage causes the non-differential comparator to change its output state. The UVLO circuit has a hysteresis controller configured for adjusting the compare voltage such that the power supply voltage has at least two threshold voltages to cause the non-differential comparator to change states. The non-differential comparator comprises a flipped gate transistor with a gate-to-source threshold greater than a normally gated transistor.

An under-voltage lockout (UVLO) circuit configured for indicating that an electronic device may be enabled and disabled based on threshold levels of a power supply voltage. The UVLO circuit has a non-differential comparator configured to have a fixed threshold voltage. A voltage divider having a first terminal connected to the power supply voltage and configured to adapt a compare signal applied to the non-differential comparator to be proportional the power supply voltage such that a desired threshold voltage for the power supply voltage causes the non-differential comparator to change its output state. The UVLO circuit has a hysteresis controller configured for adjusting the compare voltage such that the power supply voltage has at least two threshold voltages to cause the non-differential comparator to change states. The non-differential comparator comprises a flipped gate transistor with a gate-to-source threshold greater than a normally gated transistor.

The invention relates to a control circuit for protecting an electrostatic spray-coating apparatus, which has a high-voltage supply, against spark discharge. The control circuit has a disconnection device for automatically disconnecting the high-voltage supply, and has a device for detecting abnormal operation of the high-voltage supply. The device for detecting abnormal operation of the high-voltage supply is designed to monitor at least one parameter which is characteristic of the operation of the high-voltage supply, and to output a corresponding disconnection signal to the disconnection device when the at least one parameter which is characteristic of the operation of the high-voltage supply exceeds or falls below a predefined or predefinable limit value.

Provided is a relay device that can switch conduction of a current flow path between power storage units on and off, and can suppress a decrease in the output of the power storage units if an abnormality occurs. A relay device includes: a conductive path; a switch unit switched between an ON state, and an OFF state; a coil connected in series to the switch unit; a first voltage detection unit configured to detect a voltage of the conductive path at a position on a first power storage unit side; a second voltage detection unit configured to detect a voltage of the conductive path at a position on a second power storage unit side; and a control unit configured to switch the switch unit to the OFF state if a value detected by the first voltage detection unit and/or the second voltage detection unit indicates a predetermined abnormal value.

Provided is a relay device that can switch conduction of a current flow path between power storage units on and off, and can suppress a decrease in the output of the power storage units if an abnormality occurs. A relay device includes: a conductive path; a switch unit switched between an ON state, and an OFF state; a coil connected in series to the switch unit; a first voltage detection unit configured to detect a voltage of the conductive path at a position on a first power storage unit side; a second voltage detection unit configured to detect a voltage of the conductive path at a position on a second power storage unit side; and a control unit configured to switch the switch unit to the OFF state if a value detected by the first voltage detection unit and/or the second voltage detection unit indicates a predetermined abnormal value.

Apparatus detects an electrical fault in a primary tap having a plurality of distribution transformers each provided in a distribution circuit along a length of the primary tap, on a power distribution system. The apparatus includes a voltage monitor provided at each of the distribution circuits for monitoring a voltage in a corresponding distribution circuit, a controller in communication with each of the voltage monitor for receiving the voltage monitored and transmitted by the voltage monitors, and a fuse isolator configured to electrically connect the primary tap to a high voltage on the power distribution system and electrically disconnect the primary tap from the high voltage on power distribution system when activate. A fuse isolator actuator in communication with the controller is provided for activating the fuse isolator responsive to a control signal from the controller when a fault in the primary tap is detected by the controller, which determines that a fault exists in the primary tap based on the voltages monitored by the plurality of voltage monitors.

A method for operating an electronic circuit breaker having a semiconductor switch that is connected between a voltage input and a load output and that is driven as a function of the output voltage sensed at the load output during the switching on and/or cutting in of a capacitive load, wherein the output voltage is compared with a stored voltage threshold value, wherein when the voltage threshold value is reached or negatively exceeded, a current limit, to which a load current carried by the semiconductor switch is limited, is increased from a nominal value to a first step value increased therefrom, wherein the current limit is reduced stepwise from the first step value to the original nominal value, and wherein the semiconductor switch is opened if the output voltage does not reach the voltage threshold during a triggering time after the stepwise reduction of the current limit.