Provided are a complex multifunctional relay system capable of complexly performing an overcurrent blocking function, an arc blocking function, and an earth leakage blocking function by a relay circuit, and a control method therefor. The complex multifunctional relay system includes an AC circuit including a hot line and a neutral line, a power control means connected in parallel to the hot line, insulation differential amplifiers circuit-connected to the hot line and the neutral line through current shunts, a microprocessor connected to the power control means and the insulation differential amplifiers to perform monitoring and control the power supply of the power control means, a first comparator connected to the current shunt and the insulation differential amplifier and connected to the microprocessor so as to check ground fault, and a second comparator connected between the current shunt/the insulation differential amplifier and the microprocessor so as to check arc fault.

A device for testing the operation of a protection unit of an electrical network. The test device includes a generator for generating a pulse train in a secondary winding of a current transformer according to a profile of frequencies such that a measurement of the pulse train after passage through a low-pass filter is lower than a selected trip threshold, and a processing circuit arranged to identify a presence of the pulse train in a signal delivered by a second secondary winding of the current transformer. A protection unit including such a test device and to a method for testing an electrical protection unit.

A solid state circuit breaker assembly includes a transistor, a transient voltage suppression device, and a circuit board. The transistor and/or the transient voltage suppression device may be electrically connected to the circuit board. The solid state circuit breaker module may be configured to be connected to one or more non-scalable modules to regulate current. The solid state circuit breaker module may be configured to receive one or more scalable modules. The transistor and/or the transient voltage suppression device may be disposed on the circuit board in a substantially symmetrical configuration.

Provided are a complex multifunctional relay system capable of complexly performing an overcurrent blocking function, an arc blocking function, and an earth leakage blocking function by a relay circuit, and a control method therefor. The complex multifunctional relay system includes an AC circuit including a hot line and a neutral line, a power control means connected in parallel to the hot line, insulation differential amplifiers circuit-connected to the hot line and the neutral line through current shunts, a microprocessor connected to the power control means and the insulation differential amplifiers to perform monitoring and control the power supply of the power control means, a first comparator connected to the current shunt and the insulation differential amplifier and connected to the microprocessor so as to check ground fault, and a second comparator connected between the current shunt/the insulation differential amplifier and the microprocessor so as to check arc fault.

Electrical current sensing and monitoring methods include connecting a compensation circuit across a conductor having a non-linear resistance such as a fuse element. The compensation circuit injects a current or voltage to the conductor that allows the resistance of the conductor to be determined. The current flowing in the conductor can be calculated based on a sensed voltage across the conductor once the resistance of the conductor has been determined.

A heating ventilation and air-conditioning system is disclosed and includes: at least one analog-to-digital converter configured to sample a voltage signal on or across one or more power lines to provide samples, the one or more power lines supplying power to a compressor; a voltage-based protection module configured to execute one or more voltage-based protection algorithms to protect the compressor; and a soft starter detection module configured, based on the samples, to detect i) presence of a soft starter, and ii) activity of the soft starter ramping up current to the compressor, and to, based on detecting the presence of the soft starter and the activity of the soft starter, disable voltage-based protection provided by the voltage-based protection module.

Systems and methods for accurate and fast measurement of junction temperature for power modules are provided. Such systems and methods include a one or more power transistors that each have a respective die surface over which is positioned and electrically coupled to a conductive overlay. A temperature sensor is physically bonded to a top surface of the conductive overlay to provide a direct temperature measurement for the one or more power transistors.

A power cord with leakage current detection and interruption (LCDI) function includes at least two power supply lines, at least two insulating layers respectively covering the at lease two power supply lines, at least two leakage current detection lines respectively disposed around the at least two insulating layers, including a first leakage current detection line and a second leakage current detection line, at least one connector line, electrically coupled to the first leakage current detection line and/or the second leakage current detection line, and at least one insulating structure, covering at least one of the at least two leakage current detection lines, to electrically insulate the first and second leakage current detection lines from each other.

A thermal protector including a body integrally connected to a magnet wire terminating feature.

A protective circuit protects against overheating of the stator windings of an EC motor. The stator windings are connected to a semiconductor output stage which is designed for time-offset control of the stator windings using a driver circuit of a commutation controller. The protective circuit has two redundant sensor circuits, wherein two resistance-dependent sensor elements connected in series are provided in the first sensor circuit and one resistance-dependent sensor element is provided in the second sensor circuit. The first and the second sensor circuits are connected, respectively, to two evaluating circuits separated from each other and cause an interruption of the driver circuit using switch-off means when a system-specific resistance value of the first sensor element or the one sensor element associated with the second sensor circuit is reached.