Exercício Unesp 2014 - A figura é o esquema simplificado de um disjuntor termomagnético utilizado

The figure is a simplified diagram of a thermomagnetic circuit breaker used for the protection of residential electrical installations. The circuit consists of a low-resistance resistor R; a bimetallic strip L, composed of metals X and Y; an electromagnet E; and a pair of contacts C. This pair of contacts tends to open due to the action of spring M2, but the actuator arm A prevents this, with the help of spring M1. The electromagnet E is designed to attract the end of actuator A only in case of very high current (short circuit) and, in this situation, A rotates in the indicated direction, releasing the opening of the pair of contacts C by the action of M2. Similarly, R and L are designed so that the latter does not touch the end of A when the circuit is traversed by a current up to the nominal value of the circuit breaker. Above this value, the heating causes the bimetal to touch actuator A, interrupting the circuit in a manner identical to that of the electromagnet. (Adapted from www.mspc.eng.br.) Given a high current flowing through the circuit breaker in the direction shown in the figure, If you want to support my work, contact me at: [email protected]