Power Take-off

A power take-off or power takeoff (PTO) is a term for methods of taking power from an operating power source, such as a running engine, which can be used to provide power to attachments or separate machines.

Most commonly, it is a splined driveshaft on a tractor or truck designed so that a PTO shaft, a kind of drive shaft, can be easily connected and disconnected. The power take-off allows implements to draw energy from the engine.

Semi-permanently mounted power take-offs can also be found on industrial and marine engines. These applications typically use a drive shaft and bolted joint to transmit power to a secondary implement or accessory. In the case of a marine application, such shafts may be used to power fire pumps.

In aircraft applications, such an accessory drive may be used in conjunction with a constant speed drive. Jet aircraft may have permanently installed PTO shafts which are used to power engine accessories. In some cases, aircraft power take-off systems also provide for putting power into the engine during engine start.