When choosing a planetary gearbox, you need to use the outcome to determine its size and gear ratio. This is a most important balance between performance, cost, size, and efficiency. Well-known manufacturers have advisory methods for modeling. They start each project with deep learning about specific speeds, torques, situations, and machine performance.
You may also use your experience and knowledge to identify and choose the cost-effective, correct, and reliable planetary gearbox. An expert provides you a gearbox that can work without any trouble for many years.