“Speed ratio”, also known as “transmission ratio”, its calculation formula is: Speed ratio = Motor output revolution ÷ Reducer output revolution.
Next, we will introduce the calculation methods in two common situations for you:
1. When the motor power, speed ratio and service factor are known, the calculation formula of the reducer torque is as follows:
Reducer torque = 9550 × Motor power ÷ Input revolution of motor power × Speed ratio × Service factor
For example, if the motor power is 10kW, the input revolution of the motor power is 1450 rpm, the speed ratio is 10, and the service factor is 1.2. Then the reducer torque = 9550 × 10 ÷ 1450 × 10 × 1.2 = 8065.5 N·m.
2. When the torque, the output revolution of the reducer and the service factor are known, the calculation formula for the required motor power of the reducer is as follows:
Motor power = Torque ÷ 9550 × Input revolution of motor power ÷ Speed ratio ÷ Service factor
Suppose the torque is 5000 N·m, the output revolution of the reducer is 50 rpm, the service factor is 1.1, and the input revolution of the motor power is 1450 rpm. Then the motor power = 5000 ÷ 9550 × 1450 ÷ 50 ÷ 1.1 ≈ 13.5kW