ELECTRONIC THERMAL RELAY AND APPROPRIATE THERMAL ELEMENT

摘要

An electronic thermal relay is disclosed which can be associated with a multiphase electric load for generating a pre-alarm and/or an order for cutting off the power supply to the load in the case of a current overload in at least one phase or an imbalance between phase currents. With each phase is associated a thermal element with a resistive heating element through which the phase current flows, a resistive sensor transmitting to a signal processing circuit a signal representative of the heating and a thermal memory mass. The heating element is thermally coupled to the sensor and to the memory mass by a coupling body whose thermal inertia is less than that of the memory mass.