ERIC CONSTANS AND ROWAN UNIVERSITY

Most commonly-encountered geartrains are relatively simple, having only one input and one output, and thus only one overall ratio. The planetary gearset is much more versatile, since it has two inputs and one output. As we will see, this versatility comes at a price: planetary gearsets are much more complicated to design and analyze than ordinary gearsets. They often behave in very counterintuitive ways, which makes their use all the more difficult (but interesting!) As with ordinary gearsets, however, a few simple rules can be used to determine the performance and efficiency of any planetary gearset... Like all planetary gearsets, the gearset above has two inputs and one output. We may freely choose which shafts are the inputs and which is the output, as shown in the table below. In many cases, one of the inputs is fixed, so that there is a single gear ratio for the set. In other cases, such as in a hybrid powertrain, neither input is fixed, and the output depends upon both input..