| 摘要 |
PURPOSE:To detect the life of a contact, by mounting a contact-bonded terminal having a temp. sensor embedded therein to the terminal plate bonded to a contact stand having the contact mounted thereto in a freely detachable manner and performing alarming/display in accordance with the output of the temp. sensor. CONSTITUTION:In an electromagnetic contact device, the temp. sensor 14 of a contact life detector is constituted, for example, by embedding a PTC thermistor in the cylindrical part 22a of a contact-bonded terminal 22 by an insulating substance 22b such as an epoxy resin and a lead wire 15 is led out from the thermistor to the outside. This temp. sensor 14 is tightened to a terminal plate 3 in a freely detachable manner by a terminal screw 3a and connected to the relay unit 16 mounted to the lower part of the electromagnetic contact device by the lead wire 15. When a fixed contact 1 and a movable contact are consumed and the temps. of both contacts rises during the supply of a current to load, the resistance of the thermistor 14a increases and a current is decreased and, therefore, the relay unit 16 is operated to cut off the current of an electromagnetic coil 10 and an alarm/display apparatus is actuated. |
