1)good price 2)with kinds of protective functions 3)with RS485 communication interface PurposeQJR series of mining explosion-proof and intrinsically safe vacuum AC soft starter is innovative optical, mechanical, electrical product. It is suitable to the asynchronous motor of AC rated voltage 1140,660V.It is widely used in coal mine well, open-pit mine, metallurgy mill, harbors and wharf, coal ...