Polarized electromagnetic relay

In a polarized electromagnetic relay comprising:

• a base made of magnetic material;
• a contact assembly including at least one movable contact for contact with at least one fixed contact;
• a polarized electromagnet mounted on said base and comprising;
• an excitation coil,
• an armature extending through said coil and pivotally supported at its one end to said base with said one end magnetically coupled to said base,
• a pair of first and second pole members which are magnetized to opposite polarity by a permanent magnet coupled thereto,
• said first and second pole members defining therebetween a magnetic gap into which the other end of said armature extends such that said armature is movable between a rest position where the other end of said armature is attracted to said second pole member and a set position where the other end of said armature is attracted to said first pole member,
• said first pole member being magnetically coupled said base such that a magnet flux from said permanent magnet circulates through said first pole member, said base, said armature, and through said second pole member for attracting said armature to said rest position when said coil is deenergized and that a coil flux developed upon the energization of said coil circulates in an opposing direction to said magnet flux through said armature, said base, said first pole member and returns back to said armature for attracting said armature to said set position;
• said armature operatively connected to said movable contact for bringing said movable contact into and out of said fixed contact as said armature moves between said set position and rest position;
• a cover fitted over said base to enclose therebetween said electromagnet and said contact assembly;
• said relay characterized in that said cover is made of magnetic material magnetically coupled to said base and in that said second pole member is positioned adjacent to said cover to define therebetween such an air gap that is cooperative with said second pole member, said armature, said base, and said cover to form an auxiliary flux loop which permits an additional coil flux caused by said coil energization to circulate therethrough in an opposing direction to said magnet flux at least at a portion between said second pole member and said armature.