Electromagnetic contactor is fitted with an electromagnet sensitive to over-currents, to cause the limitation and cut-off of excess currents

An electro-magnetically controlled current limiting circuit breaker comprising:

• (a) a housing,
• (b) at least two stationary contacts arranged within the housing in spaced apart electrically isolated relation,
• (c) a movable contact bridging member in said housing, having first and second sides and a pair of contact portions engageable with said stationary contacts respectively,
• (d) operating means for longitudinally moving said movable contact bridging member between an open position in which said contact portions are out of engagement with said stationary contacts and a closed position in which said contact portions are in engagement with said stationary contacts, and,
• (e) an electro-magnetic actuator having a longitudinally movable armature,
• (f) means for energizing the said actuator, whereby, when the said energizing means are operative, the said armature is moved from a first position in which the said armature is separate from the actuator and a second position in which the said armature is attracted by this actuator,
• (g) second resilient means resetting the armature into said first position when the energizing means are not operative,
• (h) said operating means comprising first resilient means located on said first side between said bridging member and said housing and adapted to move said bridging member into said closed position, and thrust means located on said second side between said bridging member and said movable armature, and adapted to move said bridging member into said open position when said energizing means are not operative and said armature is in the first position,
• (i) said circuit breaker further comprising current-overload-responsive means located between said bridging member and said armature,
• (j) circuit means serially connecting the said overload responsive means and the said stationary contacts and bridging member,
• (k) said overload responsive means comprising a yoke, a coil and a longitudinally displaceable plunger having a first stable position in which it is engaging the said yoke, and a second stable position in which said plunger is separate from the said yoke, the first position being obtained when the current flowing through the said circuit means exceeds a predetermined value and the second position being obtained when the said current does not exceed the said predetermined value,
• (l) said circuit breaker further comprising striking means located between said bridging member and said armature, and adapted to cooperate with said plunger, for longitudinally moving said bridging member into a further position when said plunger is in its first stable position, the said further position being more remote from the stationary contacts than the said open position,
• (m) said striking means and thrust means acting on the surface of said bridging member, substantially at the same portion thereof,
• (n) said overload responsive means further comprising a further armature having an aperture through which passes the said plunger, said further armature being displaceable from a first position which is obtained when the current flowing through the said circuit means exceeds a further predetermined value which is lower than the said predetermined value, to a second position which is obtained when the said current does not exceed the said further predetermined value,
• (o) said overload responsive means further comprising switch means serially connected with the energizing means of said electro-magnetic actuator and the further armature cooperating with said switch means to open said switch means when the said further armature is in its first position,
• (p) third resilient means mounted adapted for resetting said plunger into its second stable position,
• (q) resilient hook means mounted for latching said plunger into its first stable position,
• (r) said plunger having a projecting portion which cooperates with said further armature for displacing the said further armature into its first position when said plunger is displaced towards its first position.