Low voltage current-limiting breaker based on forced air expulsion

Abstract

A low-voltage current-limiting circuit breaker based on forced-air arc blowing. An arc extinguishing chamber, an arc extinguishing grid and an arc blowing device. The arc blowing device is composed of a piston, a nozzle, a cylinder, a transmission connecting rod, an energy storage spring and a pull rod. The transmission connecting rod is connected with the piston to transmit force to the piston; the cylinder, the piston and the spout together form a semi-sealed air chamber, and only the spout of the entire air chamber is always in communication with the outside of the air chamber. When the circuit breaker is opened and closed, under the action of the force of the transmission link mechanism, the piston reciprocates in the air cavity along the wall of the cylinder accordingly, thus generating a forced air flow at the nozzle of the air cavity to blow to the arc, increasing the extinguishing effect. The convective heat transfer of the gas in the arc chamber cools and elongates the arc and accelerates the movement of the arc to achieve the purpose of shortening the current breaking time and increasing the arc voltage.

Description

technical field [0001] The invention relates to a current-limiting technology applied to a low-voltage circuit breaker, in particular to a low-voltage current-limiting circuit breaker based on forced air blowing arc. Background technique [0002] Current-limiting breaking technology occupies a very important position in the switching electrical appliance industry, and excellent current-limiting performance is an indispensable link for switching electrical appliances. By enhancing the current limiting performance, the breaking capacity of the circuit breaker can be greatly improved. The current-limited breaking problem of low-voltage circuit breakers requires that the breaking time of the circuit breaker be short enough to allow the short-circuit current to be broken before reaching its expected peak value. In principle, the current-limiting technology of low-voltage circuit breakers mainly includes: quickly opening the contacts to shorten the current breaking time, increasi...

AI Technical Summary

Problems solved by technology

However, while the superconducting current limiting technique works well, it is expensive and not suitable for general industrial applications

[0005] The method of using the arc striker is to use the electromagnetic force generated by the arc striker to elongate the arc and drive it into the arc extinguishing chamber. The recovery speed of the dielectric strength in the head gap is fast, and the arc can move quickly along the arc-leading path. At present, under the condition of high current, the arc stays in the contact area for a long time, resulting in excessive loss of contact material.

PTC current-limiting resistors are easily affected by external factors, and are not effective in limiting low-value currents, so there is no large-scale promotion

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