Mechanism of interaction between electric arc and breaking chamber in low voltage current limiting circuit breakers

The authors survey different types of contact arrangements with simple, double, and quadruple arc interruption in current-limiting, low-voltage, protective switching devices. The influence of the arc commutation from moving contact arm to commutation bar is discussed. A rapid electromagnet with a rotating armature is introduced. The performance of the electromagnet has been investigated by the finite-element method. The same method is used to study the configuration of the arcing chamber and the influence of different parameters on the contact repulsion forces. The experiments have been carried out using a capacitor bank. It is shown that the motion of the contact arm and the magnetic blast of the arc, its elongation, and its commutation have to be coordinated in such a way that the device functions over the entire fault current region. A sophisticated breaking chamber is needed to obtain a high short-circuit interrupting capacity within a given geometry. A good arcing process is the one that displaces the 'thermal conflict' between the arc and the other elements of the chamber from the contact area to the deionization plate package.<
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