| 摘要 |
In a clapper type contactor (10) having a magnetic latch (20) which retards the movement of the armature until the magnetic force builds to a level that will carry the armature through its complete motion without hesitation Often times in the past, clapper type contactors would have their armatures move prematurely before the magnetic force builds to a level that will carry the armature through its complete motion without hesitation. Contactors including an auxiliary arm spring as well as a closing spring are especially prone to this condition with worn contact tips. The magnetic latch circuit described herein eliminates the foregoing problem by retarding the armature movement until the magnetic force builds to a level that will carry the armature through its complete motion without hesitation. The magnetic latch circuit includes the core (14) of an electromagnetic coil (12), a magnet frame (16) upon which the core and coil are mounted, a magnetic latch (20) having a stop surface (52) resting upon the magnetic frame (16) and a pair of ears (50) extending up from the stop (52) for securing the magnetic latch (20) to a pivoted contact arm (22) and an armature (18) fixedly attached to the contact arm (22) and pivoted therewith adjacent one end of the latch plate and extending down from the contact arm, and an air gap between the armature (18) and the core (14) of the coil (12). These elements complete a flux path for the magnetic circuit. Shortly after the current begins to build in the coil upon energization of the same, the magnetic latch plate (20) goes into saturation and then an additional parallel flux path is established between the core, the magnetic frame, through the heel air gap of the armature, through the armature, and finally through the armature core air gap to complete the circuit. |
