YB2 series flameproof three-phase asynchronous motors proof mark for the ExdI, ExdIIAT4, ExdIIBT4, ExdICT4 of four, respectively, for coal, mine fixed equipment and factory IIA / IIB / IIC level, temperature class T1-T4 group combustible gas and air to form an explosive zone and Zone 2 dangerous places. Flammable gases, vapors see Appendix BG3836.1 Appendix B "flammable gases and vapors according to their maximum experimental safe gap (MESG) and the minimum ignition current (MIC) classification, for example." This series of standards:. JB/T7565.1-2004/JB/T7565.4-2004 flameproof three-phase asynchronous motors are marked with signs successor model Frame, frame length, core length, number of poles. On motor terminal box cover with a flag indicating Ex explosion-proof electrical equipment. ExdI/ExdIIBT4 has proof mark on the nameplate, and its significance see proof electrical explosion-proof mark, for example. Explosion-proof motors working conditions: 1, no more than 1000 meters above sea level; 2, ambient air temperature changes with the seasons, but not more than 40 degrees Celsius; 3, the wettest month average maximum relative humidity of 90%, while the average monthly minimum temperature production no higher than 25 degrees Celsius; 4, the lowest ambient air temperature of minus 15 degrees Celsius; 5, while the motor is running, the power supply voltage and frequency deviation shall be rated GB755-2000 requirements (rated frequency 50HZ).