Passive monitoring the integrity of current sensing devices and associated circuitry in GFCI and AFCI protective devices is provided. A protection circuit interrupter employs a capacitively coupled noise signal obtained by an arrangement of one or both of line side arms relative to a Rogowski coil. The noise signal is monitored while the line and load sides of a protective circuit interrupter are disconnected, and the connection of the line and load sides disabled if the noise signal fails to correlate sufficiently to a reference noise cycle. When the line and load sides are connected, the RMS value of the observed current signal is monitored such that the line and load sides are disconnected if the observed current signal fails to meet an RMS threshold. The observed current signal is compensated by subtracting the reference noise cycle prior to monitoring for the fault condition applicable to the protective device.

A system includes three switches each having a single pole and dual throws. The respective single pole is on a supply side of the each respective switch. The dual throws are on a load side of each respective switch, and include a respective normally open (NO) throw and a respective normally closed (NC) throw. A first voltage detector is connected from the single pole of the first switch to the NC throw of the third switch. A second voltage detector is connected from the single pole of the second switch to the NC throw of the first switch. A third voltage detector is connected from the single pole of the third switch to a NC throw of the second switch.

A self-test module of an electronic circuit breaker includes a power supply assembly with a rechargeable battery, a self-test enablement assembly, an induced power supply assembly, a boost power supply, and a micro control unit (MCU). The self-test enablement assembly is connected to the rechargeable battery and includes an enablement button, a capacitor and a first power chip connected in series. The induced power supply assembly includes a buck chip. The boost power supply includes a second power chip and a boost chip connected in series. The MCU includes a plurality of pins that are connected to the first and second power chips, the buck chip, and the boost chip. The self-test module has two working modes; the electronic circuit breaker may be provided with or without a load current. The MCU operates the self-test procedure, indicates the self-test status, and maintains the indication for a period of time.

An electric motor is connected to a voltage source via a drive circuit and, between the drive circuit and the voltage source, the operating switch is arranged for the switching of the supply voltage (U) of the voltage source as the input voltage (U.sub.E) on the drive circuit. Following the switch-out of the electric motor, the input voltage (U.sub.E) on the drive circuit is monitored and a gradient of a rising voltage ramp (dU/dt) of the input voltage (U.sub.E) is determined. The gradient of the rising voltage ramp (dU/dt) of the input voltage (U.sub.E) thus determined is compared with a predefined limiting value and, in the event of an overshoot of the predefined limiting value, the operating switch is detected as closed, and the electric motor is restarted via the drive circuit.

Implementations of ground fault circuit interrupter (GFCI) self-test circuits may include: a current transformer coupled to a controller, a silicon controlled rectifier (SCR) test loop coupled to the controller, a ground fault test loop coupled to the controller, and a solenoid coupled to the controller. The SCR test loop may be configured to conduct an SCR self-test during a first half wave portion of a phase and the ground fault test loop may be configured to conduct a ground fault self-test during a second half wave portion of a phase. An SCR may be configured to activate the solenoid to deny power to a load upon one of the SCR self-test or the ground fault self-test being identified as failing.

A switch control apparatus and method to diagnose whether a plurality of switches are controllable and effectively control the plurality of switches. According to an aspect of the present disclosure, it is possible to effectively maintain the states of the switches through a plurality of processors.

A collecting and measuring method has corresponding a contacts group to a key of a computer keyboard; corresponding a contacts group state to a key state; corresponding a first keys group and a second keys group to a first power contacts group and a second power contacts group respectively; obtaining and storing a first values group and a second values group when the first keys group and the second keys group are closed respectively; calculating a difference value between the second and first values groups; dividing the difference value by the device frequency value to get a time value; and storing the time value. The time value is a conduct transition time value of a corresponding pole.

An embodiment electronic circuit includes an electronic switch comprising a load path, and a control circuit configured to drive the electronic switch and configured to operate in one of a first operation mode and a test mode. The control circuit comprises a test mode input and is configured to operate in the test mode based on a test signal received at the test mode input. The control circuit in the first operation mode is configured to generate a first protection signal based on a current-time-characteristic of a load current of the electronic switch and drive the electronic switch based on the first protection signal.

A switch monitoring circuit has an external input terminal connected to a switch, a voltage applying unit that applies a driving voltage to the external input terminal, a voltage detecting unit that detects a change in the voltage at the external input terminal, a control unit connected to the voltage applying unit and voltage detecting unit, and a charge storage unit connected to the external input terminal and voltage applying unit. The charge storage unit has a voltage applying terminal to which the driving voltage is applied, a first resistive element, one of the terminals of which is connected to the external input terminal and the other of the terminals of which is connected to the voltage applying terminal, and a capacitive element, one of the terminals of which is connected to the voltage applying terminal and the other of the terminals of which is grounded. The capacitive element performs charging from the voltage applying terminal and discharging to the voltage applying terminal.

A circuit breaker characteristic monitoring device monitors the operation of a circuit breaker to estimate the amount of consumption of a movable contact and fixed contacts included in the circuit breaker. The device includes an operating time measurement unit to measure at least one of closing time, which is the time required for the circuit breaker to be closed after starting a closing operation, and opening time, which is the time required for the circuit breaker to be open after starting an opening operation, and a contact consumption amount estimation unit to estimate the amount of consumption of the movable contact and the fixed contacts on the basis of the result of measurement performed by the operating time measurement unit and travel speed of the movable contact during the closing operation or the opening operation for which the measurement result is obtained.