Vacuum contactors utilize vacuum bottle encapsulated contacts to suppress the arc. This arc suppression allows the contacts to be much smaller and use less space than air break contacts at higher currents. As the contacts are encapsulated, vacuum contactors are used fairly extensively in dirty applications, such as mining. Vacuum contactors are only applicable for use in AC systems. The AC arc generated upon opening of the contacts will self-extinguish at the zero-crossing of the current waveform, with the vacuum preventing a re-strike of the arc across the open contacts. Vacuum contactors are therefore very efficient at disrupting the energy of an electric arc and are used when relatively fast switching is required, as the maximum break time is determined by the periodicity of the AC waveform.Ambient temperature: -25ºC~+40ºC Altitude: ≤2000 Humidity: Relative humidity on daily average less than 95%, on monthly average less than 90%. Water vapor pressure on daily average less than 2.2kPa, on monthly average less than 1.8kPa. No normally violent vibration.
