This is a small model of planetary gearbox, which will help you to understand how planetary gearboxes work.

Assembly instructions:

1.

First print all of the models you see on the picture (all of the stl. files you see in files tab)

2.

Take the carrier shaft glue it to the carrier. I recommend using super glue.

3.

Glue the internal gear shaft to internal gear.

4.

Glue the Stand cap onto the stand as shown in the picture.

5.

Put the planetary gears on the carrier and glue the caps on top, but don't glue it to the gears.

6.

Insert the carrier and sun gear inside the internal gear and glue the handles in one row as shown.

7.

Now you have a finished planetary gearbox, you can try different combinations with the handles. For example: hold the blue (internal gear) handle and rotate the yellow (sun gear) handle and you will have a gear reduction on planetary gears handle.

But this is just one of the six combinations you can get.