The influence of low air pressure, irradiation and electromagnetic interference on the performance of relay
Low air pressure
1. Under low air pressure, the heat dissipation condition is bad, especially under high temperature and low air pressure, the convection effect is weakened, and the heat conduction is the only way to heat the small reed. When switching the rated load, the temperature of the reed can be as high as 300 ℃. It is difficult to extinguish the arc, increase the duration of the arc, intensify the evaporation of the contact metal, shorten the service life, and reduce the breaking capacity of the contact.
2. It is difficult for the coil to dissipate heat and the temperature rise is accelerated, which causes the change of the parameters of closing and releasing.
3. Under low air pressure, the dielectric strength is reduced, the insulation between contacts is reduced, and a channel may be formed on the insulator base plate. Generally speaking, the insulation level will be reduced by about 10% for every 1000 meters above sea level.
Under severe nuclear radiation, some organic materials will become dust. The molecular bonding chain of polymer insulation material is destroyed, and the insulation performance is reduced until it fails. For example, the radiation resistance of polytetrafluoroethylene film material is very poor.
Electromagnetic relay is operated by the action of electromagnetic force. When it is used around the strong magnetic field element and the strong stray field instrument, pay attention to the distribution position and the distance from the magnetic interference source. Otherwise, the reliability of action will be endangered. The high frequency power supply will also cause the relay to be heated by induction and cause thermal damage.