1. Reduction ratio: The helical planetary reducer should be as close to the ideal reduction ratio as possible to ensure the ideal speed.

　　2. Installation size: the size of the front end of the servo motor.When selecting a planetary reducer, the input end of the planetary reducer must be exactly the same size as the output end of the servo motor.

　　3. Weight: Next, you have to consider the weight of the motor.A kind of helical planetary reducer is only allowed to be matched with a motor of less than a certain weight. The motor is too heavy and long-term operation will damage the input flange of the reducer.

　　4. Torque: For the life of the reducer, the calculation of the torsion force is very important, and pay attention to the maximum torque value of the deceleration, whether it exceeds the maximum load torque calculation formula of the helical planetary reducer: the maximum output torque of the servo motor × The reduction ratio × efficiency of the reducer is less than the torque required by the planetary reducer.

　　5. Backlash of backhaul: it is what we often call "arc minutes", unit: arcmin.The smaller the return clearance, the higher the accuracy and the higher the cost. The user can choose a helical planetary reducer that meets its accuracy requirements.

　　When choosing a helical planetary reducer, the lateral/radial force and average life should also be considered.The reducer with large lateral/radial force is relatively reliable in installation and use, and it is not easy to cause problems.Usually its average life is much longer than the life of the equipped servo motor.