Patent ID: 6018284
Filing Date: 2000-01-25
Classification: H01H

Abstract:
A low voltage circuit breaker with high electrodynamic strength comprising:a frameone or more poles comprisinga pair of contact means comprising a movable contact means and another contact means, the movable contact means comprising a support carrier movable with respect to the frame between an open position and a closed position, and one or more contact fingers movable with respect to the support carrier between a contact position with the other contact means and a retracted positionelectromagnetic compensation means able to apply electromagnetic forces on the contact finger or fingers tending to keep the finger or fingers in contact with the other contact means,an opening spring designed to be released from a loaded position to an unloaded position,a kinematic system operating in conjunction with the opening spring and with the pair of contact means in such a way that release of the opening spring drives the support carrier to its open position, this system comprising a kinematic connecting means for connection with the support carrier,an opening operating mechanism comprising an opening lock designed to take a locking position in which it prevents release of the opening spring and to release the opening spring by leaving its locking position,actuating means operating in conjunction with the movable contact means and with the opening lock and able to cause ultrafast movement of the opening lock to its unlocked position when the resultant of the forces applied by the carrier on the kinematic connecting means exceeds a preset ultrafast opening threshold, wherein:the pole or poles comprise in addition electromagnetic limiting means designed to apply electromagnetic forces on the contact finger or fingers tending to drive the finger or fingers to their retracted position,the electromagnetic compensation means and the electromagnetic limiting means are such that when the current intensity flowing in the pair of contact means is less than a threshold called the limiting threshold, the finger or fingers are kept in contact with the other contact means, and that above said threshold, the finger or fingers are driven to their retracted position,and the resultant of the forces applied by the carrier to the kinematic connecting means when the current intensity flowing in the movable contact means reaches the limiting threshold is less than the ultrafast opening threshold.