The present disclosure provides an electrical plug including a first temperature detection element and a second temperature detection element. When the processor determines that the temperature of the contact pins is greater than or equal to a temperature threshold according to a first detection signal outputted by the first temperature detection element and a second detection signal outputted by the second temperature detection element, the processor disables the electrical plug to transmit the input power to a load. When one of the temperature detection elements fails, the electrical plug determines whether the temperature of the electrical plug is greater than or equal to the temperature threshold according to the other one of the temperature detection elements. The electrical plug meets the redundant design required for functional safety to avoid unexpected hazards caused by the failure of a single temperature detection element. Therefore, the stability of the electrical plug is enhanced.

The present disclosure provides an electrical plug including a first temperature detection element and a second temperature detection element. When the processor determines that the temperature of the contact pins is greater than or equal to a temperature threshold according to a first detection signal outputted by the first temperature detection element and a second detection signal outputted by the second temperature detection element, the processor disables the electrical plug to transmit the input power to a load. When one of the temperature detection elements fails, the electrical plug determines whether the temperature of the electrical plug is greater than or equal to the temperature threshold according to the other one of the temperature detection elements. The electrical plug meets the redundant design required for functional safety to avoid unexpected hazards caused by the failure of a single temperature detection element. Therefore, the stability of the electrical plug is enhanced.

A control and protection circuit of a heater, a towel heating barrel and a control method thereof are provided in this disclosure. The control and protection circuit of the heater includes a power module, a power supply module, a control module, a temperature detection module and a heating module. The power module, the power supply module and the heating module are connected in series to supply power to the heating module, the control module is in signal connection with the power supply module to control on and off of the power supply module, and the temperature detection module in signal connection with the control module. The power supply module includes a high-temperature protection switch, a fuse and a relay. The control and protection circuit of the whole heater has three levels of protection, which can not only effectively provide high-temperature protection, but also ensure service life of the heater.

The invention relates to fluid drive systems used in fluid wells and brake systems for permanent magnet wellhead direct drives. The braking controller connects or disconnects a brake resistor from a back EMF. A variable frequency drive (VFD) drives the motor and communicates with the control circuitry of the brake controller. The control circuitry monitors the brake resistor and depending on the rotational speed and direction of the motor and operating state of the VFD, disconnects or connects the brake resistor. If the direction of the motor is in reverse and above a threshold speed, it connects the brake resistor. If the direction of the motor is in reverse and below the threshold speed, the control circuitry dissipates stored back EMF through the brake controller. The amount of stored back EMF corresponds to the time to empty a pump.

A power cord includes a plug and a load connection portion connected to a load. The plug contains a plurality of plug pins which are respectively inserted in plug pin insertion holes of a power socket and connected to the power socket and a plurality of PTC thermistors, at least one of which is provided for each of the plug pins to detect a temperature of the corresponding plug pin. The PTC thermistors form one series circuit, and the power cord includes a shut-off device which turns off power supply to the load connection portion from the plug pins when a resistance value of the series circuit is equal to or higher than a predetermined value.

Systems and methods are provided for providing thermal protection to a power backplane printed circuit board. A distributed hotspot detection grid is included in the printed circuit board, the distributed hotspot detection grid comprising a plurality of passive temperature sensors spread across the printed circuit board to measure temperature increases. The plurality of passive temperature sensors are connected to a detection circuit for comparing signals from the passive temperature sensors to a reference signal. If the temperature increases on the PCB, electrical characteristics of at least one passive temperature sensor will change, resulting in a change of the input signal to the detection circuit. When the threshold is exceeded (indicating a potential short circuit or hotspot), the detection circuit outputs a shut down signal to the one or more power supplies connected to the of the backplane printed circuit board, to avoid catastrophic damage to the printed circuit board.

The invention relates to fluid drive systems used in fluid wells and brake systems for permanent magnet wellhead direct drives. The braking controller connects or disconnects a brake resistor from a back EMF. A variable frequency drive (VFD) drives the motor and communicates with the control circuitry of the brake controller. The control circuitry monitors the brake resistor and depending on the rotational speed and direction of the motor and operating state of the VFD, disconnects or connects the brake resistor. If the direction of the motor is in reverse and above a threshold speed, it connects the brake resistor. If the direction of the motor is in reverse and below the threshold speed, the control circuitry dissipates stored back EMF through the brake controller. The amount of stored back EMF corresponds to the time to empty a pump.

Respiration aiding equipment is provided, wherein the respiration aiding equipment includes a main control module, a heating loop and a heating loop protective circuit connected to the heating loop, and the heating loop protective circuit includes an acquisition sub-circuit, a suppression sub-circuit, a protective sub-circuit and a discharge sub-circuit; the acquisition sub-circuit collects input voltage of the protective sub-circuit and sends the input voltage to the suppression sub-circuit; the suppression sub-circuit clamps the input voltage and releases current through the discharge sub-circuit; and the protective sub-circuit performs short-circuit protection when the current is too high. In the present disclosure, the over-voltage protection is realized through the voltage clamp in such a manner of monitoring the voltage of the heating loop and suppressing the input voltage through the suppression sub-circuit, and then the over-current protection is realized through the protective sub-circuit when the circuit current is too high.

In a power supply control device, a temperature calculation circuit calculates a wire temperature of a wire based on the current value of a current flowing through the wire. If the wire temperature calculated by the temperature calculation circuit is lower than a temperature threshold value, a drive unit switches on or off a switch in accordance with content indicated by a control signal output by a communication unit. When the wire temperature calculated by the temperature calculation circuit rises to the temperature threshold value or higher, the drive unit switches off the switch independently of content indicated by a control signal output by the communication unit.

An arrangement for a refrigerator and/or freezer comprising an electrical or electronic component (1, 2a), and comprising detection means (2, 4) by which an electrical or thermal load of the component can be detected, wherein the detection means comprise a heat source (2) and means for the detection (4) of the heat output of the heat source, wherein the heat source is not formed by the component itself and is connected in series or in parallel to the component.