A contactor including a plunger core (100), a pull-in winding (La), a holding winding (Lm), a moving contact plate (CM) and three contacts (PC+, PC1, PC2). The contactor has three operating states: a first state with no electrical contact between the contacts, a second state with electrical contact between first and second contacts and a third state with electrical contact between the first, second and third contact. The contactor also includes an electrically controllable micro-actuator (MS) to allow or prohibit, depending on the electric current which is applied thereto, commutation between the second and third operating states, the commutation being prohibited by the micro-actuator due to a force counteracting a thrust of the moving contact plate when the micro-actuator is electrically excited. Preferably, the micro-actuator is a micro-solenoid.