A wiring device including an interrupting device and a controller. The interrupting device electrically connects one or more line terminals to one or more load terminals when the interrupting device is in a reset condition and disconnects the line terminals from the load terminals when the interrupting device is in a tripped condition. The controller is configured to, determine a frequency of an input voltage at the one or more line terminals, determine whether the frequency is within a predetermined range, and when the frequency is within the predetermined range, perform a test of the wiring device.

A system for ensuring that electrically powered medical equipment is properly grounded includes a current sensor that senses current flowing within a ground connection conductor (e.g., leakage current) for the medical equipment. The sensor may operate based on induced current. Measured current is converted to a voltage value, and the voltage value is analyzed by a processor to determine whether current is present in the ground connection conductor. If no current is present, the ground connection conductor may be faulty. If current is present, the system can also identify voltage-to-patient fault conditions.

A system for ensuring that electrically powered medical equipment is properly grounded includes a current sensor that senses current flowing within a ground connection conductor (e.g., leakage current) for the medical equipment. The sensor may operate based on induced current. Measured current is converted to a voltage value, and the voltage value is analyzed by a processor to determine whether current is present in the ground connection conductor. If no current is present, the ground connection conductor may be faulty. If current is present, the system can also identify voltage-to-patient fault conditions.

Provided by the present invention is a current overload protection apparatus. The apparatus comprises a current measuring device and a control module; the current measuring device is used to measure a current value on a current path; the control module is electrically connected to the current measuring device, and stores current threshold data; the current threshold data comprises a plurality of time intervals respectively corresponding to disconnection threshold values; the earlier the time corresponding to a plurality of time intervals, the larger the disconnection threshold value corresponding thereto; and the control module is used to receive and collect current signals within a specified time length so as to calculate the current value of the current path, and determine whether the current value is greater than or equal to the disconnection threshold values, and if so, then an overload protection step is performed to protect the load from current overload.

A method for determining an optimized TCC operating curve for an electronic interrupting device that protects a distribution transformer in a power distribution network, where the TCC operating curve is some optimized predetermined percentage above a TCC curve for normal transformer operation. The method includes providing a TCC transformer curve that identifies an allowed transformer operation current once the transformer magnetics have been stabilized and the transformer is operating normally, and determining a TCC operating curve that is defined by points along the transformer curve plus a predetermined percentage above the transformer curve, where the operating curve identifies a response time for when the electronic interrupting device will open in response to a certain current flow.

The present invention comprises a drive control unit configured such that, when a first power supply (Vin1) is abnormal, an OFF signal is simultaneously applied to the gates of first and second semiconductor switches (Q1, Q2) of a first switching element, and at the same time, an SCR switch of a second switching element and an FET bidirectional switch are turned on in order.

A desaturation protection circuit is provided. Aspects includes a main gate driver circuit driving a gate for a switch, a desaturation gate driver circuit coupled to a drain terminal of the switch, a PWM signal supply circuit configured to supply a PWM signal to the desaturation gate driver circuit, and a delay circuit, the delay circuit configured to delay the PWM signal from the PWM signal supply circuit to the desaturation gate driver circuit during a turn-on event for the switch.

A method and system is provided which monitors and regulates induced ground-line power on a structure or organism. Further a method and system is disclosed which monitors and regulates induced ground-line power by regulating and harnessing small current flows generated by induced EMF exposure on the structure or organism as they flow through the attached system to an Earth ground connection point.

A circuit includes a first transistor, a second transistor, and a sense transistor. The first current terminals of the first and second transistors are coupled together at a power supply node. The control terminals of the second and third transistors are coupled together. The second current terminals of the first, second, and third transistors are coupled together. The sense resistor is coupled between the first current terminals of the first and second transistors and the first current terminal of the third transistor. The first and second transistors are configured such that during a first mode of operation, current to a load flows through the first and second transistors, and during a second mode of operation, current to a load is discontinued through the first transistor yet flows through the second transistor.

Described are curve shapes that may be implemented in a transformer protector that provide enhanced fault protection. A transformer protector curve rating structure relates response curves to the transformer size and simplifies selection of response curves implemented within a transformer protector and associated transformer.