Firstly, the choice of decelerating motor needs to be taken into account according to the load, speed and size of your corresponding bearing equipment, such as I load about 8 cattle and output speed of 50rpm.
Then, according to the formula: P=2 PI /60*50* 8, you can calculate the theoretical power of 41.8 W, so choose a motor with 41.8 W, and go with the speed reducer of 60:1, Of course including efficiency, general advice to choose 60 w motor, calculation method is different also, of course, different forms of exercise, the most common for the rotary motion, the horizontal movement and vertical movement, in view of the rotary motion, calculation method and example, but there need to pay attention to whether lever；For horizontal motion, you can choose the power according to the formula P=F* V, and then reverse the torque, to select the suitable decelerator motor, where P is power, F is resistance, and V is speed; For vertical motion, then power is equal to gravity velocity,Add speed and calculate the torque, and select the right decelerator motor. If there is something you don't understand, ask the speed reducer directly and tell you what you need. The manufacturer will give you the right choice.