At present, there is little research on Hybrid DC contactor in China, there is no product of Hybrid DC contactor for railway locomotive. According to the robust design theory, combined with customer demand the use environment of locomotive contactor, this paper studies the pull in time release time of electromagnetic contactor, selects appropriate power electronic devices, designs implements a modular hybrid DC contactor prototype with digital analog hybrid control circuit as the core, including drive, isolation, delay, power conversion, temperature protection surge Parameter design of voltage current protection circuit tolerance design of main device parameters. Through the limit on-off test, the overload capacity of 4 times of the contactor is verified; through the reliability electrical life test, the change trend of the electrical life of the Hybrid DC contactor can be reflected, that is, the electrical life is only related to the mechanical life of the contactor, which has the advantage of long service life; the inspection report of the locomotive vehicle inspection station in the product quality supervision inspection of the Ministry of Railways shows that the prototype conforms to TB/ T2767-1996 technical conditions of DC electromagnetic contactor for locomotive.

DC contactor is widely used in railway locomotive vehicle power supply system, its reliability life directly affect the reliability life of the whole system. Arc wear exists in the opening process of electromagnetic DC contactor, the greater the power is, the more serious the arc wear is, which is the key factor causing poor reliability short electrical life of DC electromagnetic contactor. In order to eliminate reduce the influence of electric arc, a Hybrid DC contactor is designed in this paper, which uses electronic switch mechanical contact in parallel is controlled by digital analog mixed logic circuit to make the mechanical contact on off instantaneously, the electronic switch bears the load, the mechanical contact bears the load in the steady state, so as to realize the on-off without arc. Its main advantages are: (1) long life without arc; (2) high reliability; (3) environmental protection; (4) explosion proof.