In the process of motor operation, due to friction, the motor shell will produce some heat, if the motor shell overheating will damage the normal operation of the motor, so the motor shell will come with a lot of blades or fans and lubricants and other ways to cool down the motor shell, so what kind of problem is reasonable for the motor shell? We need to explain this problem from different kinds of motors:

　　1, explosion-proof occasions AC motor

　　If it is driven high-speed oil pumps, such as 2-pole motor 2890 rpm above the motor, the maximum temperature does not exceed 85 - 90 degrees, because it is a high-speed motor, so the summer temperature is generally controlled below 80 degrees, more than must be shut down (consider the insulation level of the insulated coil). Also because the motor is running in dangerous and explosive occasions, in order to ensure the safety of explosion-proof inspectors must be half an hour once, specific measurements: motor surface temperature, control in the safe temperature.

　　2, the ground non-explosion-proof occasions AC motor

　　For example, commonly used 4-pole, 6-pole motor, because the motor speed is low, so the bearings as long as the diligent refueling, if it is more than 4-pole motor motor shell temperature to maintain 70 degrees. Bearing temperature exceeds 80 degrees, is the reason for lack of oil to regular maintenance.

　　3, DC motor

　　Because most of the DC motors come with cooling fan, so the temperature is controlled within 50 degrees, the highest summer 60--6 degrees.