The Analysis of Fire Characteristics of Tumbler Switches due to Deterioration of Contacts

In this paper, the fire characteristics and mechanisms were analyzed according to deterioration of the contacts of tumbler switches. In order to deteriorate the contacts of tumbler switches, 1% NH
₄
Cl solution was dripped at the contacts of tumbler switches for 1 hour at a rate of 1 drop per second. During switching on and off, arc dispersion was taken by digital camera and high speed imaging system, and then the size and the duration of arc were recorded and analyzed. Tumbler switches were switched on and off from 10000, 30000, 50000 and 70000 times respectively in order to discover the deterioration characteristics of contacts caused by arc. After switching repetition, damaged contacts and insulators were compared to normal contacts and insulators. The results could be applicable to fire cause analysis of electrical appliances such as tumbler switches