INDIRECT MEASURING INSTRUMENT FOR CONTACTING FORCE OF CONTACT POINT

摘要

PURPOSE:To measure the contacting force of a contact point indirectly without disassembling an electromagnetic relay by finding an armature following time from a vibration signal generated in the contact switching operation of the electromagnetic relay. CONSTITUTION:When a driving signal DRV is supplied to the base of a transistor (TR) Q1 for driving a relay coil R1 connected in series with a driving power source P1, the contact point (r) of the electromagnetic relay 10 is switched from a break contact point B to a make contact point M. At this time, the vibration signal S collected by a vibration sensor 30 is inputted to a time measuring circuit 50 through an amplifying circuit 40. Then the output of an oscillation circuit OSC is counted by a counter CNT 2 only while the output of an AND circuit AND 2 goes high to obtain the armature operation following time. This armature operation following time is multiplied by a constant coefficient which is found previously experimentally to find the contact contacting force in the operation.