Patent ID: 7557684
Filing Date: 2009-07-07
Classification: H01H

Abstract:
1. An electromagnetic switch comprising: a pair of fixed contacts; a movable magnetic core configured to be moved by a magnetic attraction, thereby establishing an electrical connection between the fixed contacts; a magnetic coil; and a fixed magnetic core configured to create the magnetic attraction when the magnetic coil is energized, the fixed magnetic core having a base portion and a disc portion, the base portion being arranged to face the movable magnetic core, the disc portion being fixed to the base portion, the disc portion being formed of a stack of at least one base metal sheet and a balance metal sheet, the balance metal sheet having a thickness that is predetermined to balance a difference between a desired thickness of the disc portion and a total thickness of the at least one base metal sheet, wherein the thickness of the balance metal sheet is predetermined to balance the difference between the desired thickness of the disc portion and the total thickness of the at least one base metal sheet, and is different from the thickness of the at least one base metal sheet, and the thickness of the balance metal sheet is one of greater than the thickness of the at least one base metal sheet and less than the thickness of the at least one base metal sheet.