Patent ID: 8013695

Claim:
An electronic overload relay that is packaged in a case, the electronic overload relay comprising: a contact mechanism that is switched between a trip position at which an overload signal is transmitted and a reset position at which a standby signal is transmitted; a magnetic circuit that includes a stationary iron core, a permanent magnet, and an armature that is fixed to the contact mechanism and that is switched between a trip position at which the armature is attracted by the stationary iron core and a reset position at which the armature is separated from the stationary iron core, arranged in a circular pattern; a contact mechanism spring that separates the armature from the stationary iron core and opens the magnetic circuit to bias such that the contact mechanism is switched to the reset position; a coil that is arranged on the magnetic circuit, generates a magnetic flux in a same direction as a magnetic flux of the permanent magnet by energization when an overload is detected, thereby switching the armature from the reset position to the trip position against the contact mechanism spring, and generates a magnetic flux in a direction opposite to the magnetic flux of the permanent magnet by energization in the opposite direction when a predetermined time is elapsed after detecting an overload, thereby opening and separating the armature held at the trip position from the stationary iron core by an attracting force of the permanent magnet; a movable stopper that engages with the contact mechanism against a biasing force of the contact mechanism spring at a position where the armature is slightly separated from the stationary iron core; and a reset bar that switches the movable stopper between an engaging position where the contact mechanism is engaged and a non-engaging position.