... 2,Low noise, Little vibration 3,Power supply 380V,660V,1140V,50/60Hz 4,Cooling method: IC411 Features of YB2 ... part One, Electrical apparatus for explosive gas atmosphere>, and GB3836.2 ... :50HzProtection class:IP55Cooling method :IC411Work mode:S1Insulation class:F YB2 series electric motor chemical product machinery parts