Abstract: Under extremely cold weather conditions, the starting performance of the motor decreases sharply due to the influence of resistance torque such as fan load and internal lubricating oil, which is very easy to lead to starting failure. This is a difficult problem that restricts the normal operation of air conditioner under low temperature conditions. Through the analysis of the force on the shaft system at the moment of motor starting, it is discussed in detail from two aspects: increasing the motor starting torque and reducing the resistance torque. It is concluded that the starting problem of motor under low temperature can be solved by increasing the starting current of DC motor and adopting new low temperature resistant lubricating oil and motor bearing, and the effectiveness of the solution is verified by experiments.

Key words: Direct current motor, Ultra-low temperature, Startup performance, Starting moment, Resistance moment