I advertise everywhere that the RR1 robotic arm uses split-ring planetary gearboxes that provide very high reduction ratio. But what is the theory behind these high numbers?

The video below shows how to calculate the reduction ratio of the split ring planetary gear box. It provides very deep insight in how this type of gearbox works. I recommend to watch the video carefully and calculate in sync with my commentary.

I believe the video explains where the high reduction ratios come from. English subtitles are provided.