YB3 Series motor(Frame range 63～355) 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 Environment 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 EXD I GB, EXD II BT4 MB. It is suitable to be used in the mine where contains methane and core dust(EXD I GB), or on the equipment, which is in the place contains explosive mixture, the type II, rate A and B, from T1～T2(EXD II AT4 MB, EXD II BT4 MB) or the flammable gas, steam and the air, and normally it is used as the power equipment.