Patent ID: 8111490
Filing Date: 2012-02-07
Classification: H01H,H02H

Abstract:
1. A method for protection of a switching device controlled by a control unit through which an electric drive can be disengaged during a period of an overvoltage surge caused by a load dump in an electrical system of a vehicle, said method comprising: controlling at least one relay to engage a drive, wherein the relay directly connects the drive with ground and a supply voltage of the electrical system; monitoring the electrical system for occurrence of a load dump during engagement of said drive by detecting an overvoltage of a supply voltage in the electrical system by the control unit, wherein due to the overvoltage a current through the drive rises in a first time slot to a maximum value and drops in a second time slot connected to the first time slot to a second value, and controlling the relay to disconnect the drive from the electrical system in the case of a load dump at a time stipulated by the control unit after the first time slot.