This series have flame proof performance in accordance to GB3836.1 Explosive Atmosphere Electrical Apparatus, Part 1, General Requirements and GB3836.2 Explosive Atmosphere Electrical Apparatus, Part 2, Apparatus with Flameproof Type “d” . It is developed according to the market demands, matched with the frequency converter to achieve a wide range of smooth stepless speed regulation. speed range, dynamic response, speed accuracy, low frequency torque, slip compensation, power factor, efficiency and other aspects have great advantages. It is suitable for the coal, petroleum, chemical and other explosive gas mixture atmosphere .