Abstract: A limiting circuit breaker comprises an electrodynamic repulsion contact system, and an electromagnetic latch arranged in the vicinity of the contact system, and electrically insulated from the latter. Actuation of the latch to the active position results from the action of the electromagnetic field due to a short-circuit current flowing in the pole, so as to temporarily keep the movable contact open after repulsion. The latch is equipped with a pair of ferromagnetic brackets, and with a spring blade to return to an inactive position.

Abstract: A test circuit simulates the operation of a multipole electrical circuit breaker, and includes a pair of auxiliary terminals connected by a connection circuit to the input terminals of a bridge rectifier cell whose output is connected in parallel with the respective outputs to two other rectifier cells associated with current transformers. A first resistor delivers a first signal proportional to the maximum intensity of the mains currents. Diodes cooperate with a second measuring resistor of a residual earth leakage current discriminator. Reversing the direction of the test current flow in the test circuit is performed by simply changing the polarity of the test terminals, and enables overcurrent protection and earth leakage protection of the electronic trip device to be checked separately.