Overload protector

Abstract

The invention provides an overload protector comprising a shell, a thyristor, a diode, a control resistor, an electromagnet, a button and a divider resistor, wherein the diode is connected in series with the control resistor and then connected in parallel with the divider resistor and then connected in series with the button; the diode anode end of a circuit is connected with the live wire end of a power grid; the button end of the circuit is connected with the zero line of the power grid; besides, the anode end of the thyristor is connected with the live wire end of the power grid, and the control end of the thyristor is connected between the diode and the control resistor, and the cathode end is connected in series with the electromagnet and then connected with the zero line of the power grid; and the electromagnet is coupled with the button and ensures that the button is disconnected when the current of the electromagnet reaches an overload zero bound value. The overload protector can not only accurately realize open circuit protection when the current of a main circuit reaches overload critical current, but also be conveniently restored after open circuit.

Description

Technical field [0001] The invention relates to the field of electric power, in particular to a current overload protector with extremely high accuracy. Background technique [0002] The current home circuit is generally equipped with an overload protector, which is generally a fuse fuse, which is installed in the knife switch. Its characteristic is that when the current in the home power grid is too large, the fuse will blow due to high heat. However, the fuse Once blown, it cannot be restored and needs to be replaced to connect the circuit. This makes the follow-up work very troublesome, especially at night. It is impossible to see the internal structure of the knife after a power outage, and it is difficult to connect the fuse safely. In addition, consider As far as the heat dissipation of the fuse is concerned, in fact the specific value of its overload melting current is very inaccurate. [0003] In addition, in some demanding industrial equipment, the main overload protector...

AI Technical Summary

Problems solved by technology

[0002] Current household circuits are generally equipped with overload protectors, which are generally fuses and fuses, which are installed in knife switches. Once the fuse is broken, it cannot be restored, and it needs to be replaced to connect the circuit, which makes the follow-up work very troublesome, especially at night, after a power failure, the internal structure of the switch blade cannot be seen clearly, and it is difficult to connect the fuse safely. In addition, consider To the heat dissipation of the fuse and other issues, in fact, the specific value of the overload fusing current is very inaccurate

[0003] In addition, in some industrial equipment with high requirements, the overload protectors used mainly include thermal relays, electromagnet type tripping circuit breakers, and various deformations of the two. The former also disconnects the main circuit by deforming the metal sheet through the thermal effect. Considering the heat dissipation instability of the metal sheet, the accuracy of the overload current of the open circuit protection is not high. The latter directly attracts the armature through the electromagnet to disconnect the main circuit. circuit, to achieve overload protection, however, when the current reaches the overload critical current, the armature will be in a state of not moving, at this time, the switch is prone to arc phenomenon

Moreover, the above two overload protectors involve many mechanical motion pairs, so it is difficult to achieve greater accuracy in terms of mechanical structure. Secondly, the above overload protectors are difficult to install in the junction box of ordinary household users. middle

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