Contact Resistance Characteristics of Relay Operated in the Vicinity of Silicone-Type and Non-Silicone-Type Polymeric Cured Materials at Elevated Temperatures

Influences of vapors evaporated from a newly-developed acryl-based polymeric material (containing no silicone components) and conventional silicone-containing polymeric materials were evaluated with respect to their effects on contact resistance characteristics of relay contacts at an ambient temperature of 120°C. More specifically, a commercially-available mechanical relay (AgSnln contacts) was sealed into a can with one of the two materials, and placed in a heating chamber to operate, at an operating frequency of 0.5 Hz, 40,000 break operations of an inductive DC14V-0.4A load current, an inductive DC5V-1A load current, or a resistive DC14V-1A load current. Contact resistance values were measured at every 50 operations, and compared with the results obtained in the similar operation tests conducted at an operating frequency of 1 Hz. As a result, the relays sealed with the acryl-based non-silicone-type polymeric material showed no deterioration in contact resistances, irrespective of the load conditions or operating frequencies. On the other hand, the relays sealed with the silicone-containing material showed more significant deteriorations and fluctuations of the contact resistance characteristics in the 0.5 Hz operations as compared with the cases of the 1 Hz operations.