Switch crowbar circuit and control method thereof

Abstract

A switch crowbar circuit comprises a main contact, and accessory circuits are connected between the first electrode end and the second electrode end of the main contact in parallel. The switch crowbar circuit is characterized in that the accessory circuits comprise accessory contacts, current-limiting resistors and a three-end controllable circuit including a first voltage end, a second voltage end and a control end; the first voltage end is connected with the first electrode end, the second voltage end is connected with the second electrode end, the control end is connected with the first end of the accessory contact, and the second end of the accessory contact is connected with the first voltage end through a current-limiting resistor; when a forward voltage is supplied between the first voltage end and the second voltage end and the control end receives trigger signals, the controllable circuit is conducted; when a backward voltage is supplied between the first voltage end and the second voltage end and the control end receives trigger signals, the controllable circuit is conducted; when a forward or backward voltage is supplied between the first voltage end and the second voltage end and the control end has not trigger signals, the controllable circuit is cut off. Compared with the existing technology, the invention uses a three-port controllable circuit with control end to receive trigger signals to conduct electricity while the accessory contacts are closed so that the working current flows from the controllable circuit, thereby damaging the arcing conditions of maincontact, efficiently eliminating the voltaic arc when the main contact is closed; the circuit structure is simple, the installation and use are convenient, the arc-suppressing effect is good, and theinvention is propitious to generally wide application.

Description

technical field [0001] The invention relates to a switch arc suppressing circuit and a control method for preventing a switch electric device from drawing arc when it is closed or disconnected. Background technique [0002] Load switches, sockets, breakers, AC contactors, relays, etc. are commonly used switching appliances. These switching appliances mostly use the contact and disconnection of mechanical contacts to realize the conduction or breaking of the working circuit. However, the mechanical contacts of the above-mentioned switching appliances are at the moment of closing and separating due to the small distance between the contacts and the electric field strength is very large. At this time, arcing (discharge) phenomenon will occur, and frequent arcing will burn the switch contacts, and then It affects the service life of the switch and also reduces the reliability of the circuit. Therefore, how to effectively extinguish the arc is a problem that needs to be solved ur...

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Problems solved by technology

[0005] However, since the capacitor itself has the function of discharging in addition to the charging characteristic, the capacitor in the above-mentioned patent has high requirements for the design of charging and discharging time. If the capacitor is saturated before the main contact is completely disconnected, the capacitor The electric charge will be released, so part of the electric energy will be transferred to the main contact circuit. When the main contact is disconnected, an arc will still be generated, which cannot achieve a better arc extinguishing effect and is not conducive to general use; moreover, the patent The auxiliary circuit in the circuit can only eliminate the arc when the main switch is turned off, and the arc phenomenon will still occur when the main switch is closed again. Ideal, yet to be further improved

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