ABSTRACT
Compound planetary gear trains (PGT) consist of a few simple PGTs. The area of compound PGTs is incredibly extensive. Possible combinations of component PGTs in a compound one are estimated at several thousand. There is a particular category of compound PGTs, denoted as reduced PGTs. They are derived from two-carrier PGTs, both carriers of which have merged, that is, are reduced to a single carrier. A crude error is to consider these PGTs to be simple PGTs due to the fact that they are with only one carrier. The extraordinary diversity of compound PGTs and the complexity of processes involved may impede the designer, and this requires developing both a clear and understandable system of the gear trains, as well as a simple, comprehensible, easy-to-use, and visual way for their analysis.
