YB3 series explosion-proof three-phase asynchronous motor(Frame range 63355) is produced according to the following requirement: GB3836.1-2010《The explosive environment part one: the general requirement of the equipment》，GB3836.2-2010《The explosive en-vironment part two: the equipment of explosion-proof case to protect 》 and MT451-2011 《The general safety specification of the coal mine explosion-proof, low-voltage, three-phase asynchronous motor》.The explosion mark is EXDI GB, EXD Ⅱ BT4 MB. It's suitable to use the fixture which is in the mine include the methane and core dust(EXDI GB), or the equipment .which is in the place include the explosive mixture the type Ⅱ ,rate A and B, fromT1-T4 (EXD Ⅱ AT4 MB . EXD Ⅱ BT4 MB)of the flammable gas or steam and the air, normally it's used in the power equipment.