In pursuit of the "best" reduction transmission for an Actuator, I can across many different types of gear boxes. This was one of the more interesting ones.It was based on an old patent (reference pending)Research papers were also written.https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20150004058.pdfhttp://esmats.eu/esmatspapers/pastpapers/pdfs/2015/puchhammer.pdfThis design suffers from vibration due to a single offset disk.The outside has 12 pole pairs and the inner has 11 pole pairs. It works in a similar way to a cycloidal gearbox.