Q: Working nature of winch: the number of starts is 12 times/hour, the working time efficiency of the motor is 60%, the 24-hour working system, the tension of the winch is 100KN, and the rope speed is 40m/min. What power motor should be selected, and which working system should be selected?

　　Answer: (For reference only)

　　1. From the narrative, it can be seen that the motor operates every 5 minutes, with 3 minutes of operation and 2 minutes of shutdown or no-load.

　　2. Motor power P=F * v/ η= one hundred × 40/(60 * 09)=74KW, please recheck the mechanism efficiency according to the selected transmission mechanism.

　　3. I personally believe that the motor starts quite frequently and has a high power output. If started frequently, it will have a significant impact on the power grid. To prevent the motor from starting frequently, an electromagnetic clutch device can be installed between the motor and the mechanism to keep the motor working continuously. The motor adopts a continuous working system, with a power greater than or equal to 74KW.