Premium Series Compact Circuit Breakers

MLT, SLT, ULT, XLT Series

Premium Series Electronic Compact Circuit Breakers

MLE, SLE, ULE, XLE

Double Break Short Circuit Breaking System 

Sigma Premium Series Compact Circuit Breakers can safely interrupt high short circuit currents up to 150kA thanks to their Double Break short circuit breaking system and current limiting technology. This technology enables the switch to extinguish the arc formed on the arc extinguishing plates much more quickly and easily at the moment of circuit interruption by creating a high pressure increase in the area where these plates are located. 

In addition to traditional technologies, the Double Break breaking system;

In the Double Break breaking system, since the pair of movable rotating arms moves with a rotating system, the inertia moment on the movable arm is reduced. In such a system, the breaking operation will be very fast and easy, thus directly increasing the breaking performance. 

As shown in the figure, during contact, the movable contact bar, which has a rotation axis at the center, and the rotor, which is connected to the switching mechanism via a movable connection pin at each end of the conductor, are held. When the current supply mechanism is manipulated, the connection pin causes the rotor to move in a circular motion, and then the moving contact arm rotates counterclockwise to open the connections. In contrast, when the contacts are to interrupt a high current in the instantaneous opening function, the movable contacts, previously directed by electromagnetic force, move in the opening direction, and the operation is completed by opening the contacts with the clockwise rotation of the rotor to which they are connected. The fixed contact holder is positioned facing each end of the moving contact bar, and the fixed conductor is placed along the side surface of the moving contact bar, creating a magnetic opening field.

As a result, when a current flows, the opposing magnetic fields generated by the magnetic opening field intersect perpendicularly with the conductor arm of the movable contact bar and apply an electromagnetic force to the arm in the contact opening direction. The combination of the movable contact bar with reduced inertia moment and the more advanced electromagnetic thrust increases the switching speed. 

Additionally, the magnetic flux from the opening field also intersects perpendicularly with the arc generated between the contacts during interruption, causing a repulsive force to move toward the arc-preventing plate. When the arc reaches the plates and is broken at an early stage, the current limiter (limiter) exhibits high performance.