Abstract: This paper introduces the causes of the explosion of the explosion - proof motor of EML340 continuous miner, and analyzes the characteristics of various cooling modes of the motor. Deduced the calculation formula of the heat and the temperature rise of the motor, and calculated the calculation formula of the water cooling system. The calculation formula of the total cooling water flow rate, the actual temperature rise and the cooling water flow rate is given. The motor of the cutting mechanism is taken as an example.