Electro-pneumatic contacts with compressed air as a power

Due to the high electric and diesel locomotives main circuit voltage, current large, so is used to turn off the main circuit and open contacts must have a larger opening and contacts from the contact pressure to prevent contact temperature is too high , and ensure that there is sufficient contact arcing when disconnected and insulation capability . Electro-pneumatic contacts with compressed air as power, fully meet these requirements , which are widely used in electric and diesel  mcb circuit breaker . But electro-pneumatic contacts have their innate weaknesses : ( 1 ) it is one of the key components to soften or harden rubber cup extremely dramatic changes in temperature and deterioration and cooperation between the cylinders , causing electrical action failure , thus failure ; ( 2 ) it uses  Voltage stabilizer  air as power, complicated duct runs , to a certain extent, affected the reliability of electrical appliances ; ( 3 ) its use of the environment has  air circuit breaker  requirements. It is because of these electro-pneumatic contactors weakness in foreign countries, has been widely used locomotive circuit electromagnetic contactor. With the rapid development of rail transportation technology, machine owners electromagnetic contactor circuit to replace the electrical contacts has become one of the empty trends . Meanwhile the city subway, oil drilling , plating, wind power and other industries also require high power DC electromagnetic contactor. Therefore, the development of new magnetic contactor has become essential.