Electrodynamic compensator for high-current contact devices

Abstract

Compensators of electrodynamic repulsion forces of closed electrical contacts are designed to increase the stability of the operation of switching electrical devices when short-circuit currents flow. The possibilities of increasing the efficiency of electrodynamic compensators (one-loop and two-loop) in their traditional design are very limited. The paper analyzes an electrodynamic compensator for high-current contacts, in which the free end of the inactive contact included in the design of the compensator with contact pads is bent 180 degrees towards the axis of rotation of the inactive contact. As a result of this, the shoulder, on which the electrodynamic force of repulsion of the contacts acts, decreases. In such a design, the moment of repulsion of the contacts will also be less and the fulfillment of the condition for its full compensation is facilitated. Formulas are given for calculating the additional electrodynamic force of the considered compensator and its contour coefficient. Calculations of the additional electrodynamic effort of the breaker compensator for a rated current of 630A with a short-time withstand current of 40kA have been performed. With the length of the bent part of the inactive contact equal to 25% of the total length of the current loop, the resulting electrodynamic force of the compensator increases by 4.69%. In this case, a 25% reduction in the torque that is repulsive to the contacts occurs.