Patent ID: 6225807
Filing Date: 2001-05-01
Classification: H01H

Abstract:
A method for determining a remaining lifetime value of contacts in a switchgear, comprising the steps of:determining a contact spring action at a beginning of a parting of the contacts;during a shutdown cycle, measuring each change in the contact spring action to determine an erosion of contact points, including the steps of:measuring a run-time value of an armature path from a first start of an armature movement in a contactor solenoid actuator to a second start of an opening of a contact, the contactor solenoid actuator including a yoke and an armature, the yoke having a solenoid, the second start of the opening of the contact being determined by measuring a voltage rise of the contact, the first start of the armature movement being determined by measuring a voltage of the solenoid to determine a time of separation of the armature from the yoke,determining a length of the armature path as a function of the run-time value, anddetermining the change in contact spring action by a change in the length of the armature oath;determining an erosion of the contacts as a function of the change in the contact spring action; anddetermining the remaining lifetime value using the erosion.