An engine PTO runs off the engine thus the speed is governed by the speed of the engine. A ground PTO is ran from the rotation of the tires. Therefore the speed is governed by the speed of the rotation of the tires.
As engine rpm increases so does pto speeed And if you tach your motor to an excessive amount of RPMs while the PTO is engaged, it will destroy that PTO, leading to zero PTO RPMs.
To transfer power from the PTO or ETO (a PTO mounts to the transmission and is driven by the flywheel; an ETO runs off the engine crankshaft) usually to a hydraulic pump.
Farm tractors and some trucks and industrial engines can have a PTO or Power-Take-Off shaft that is used to power attachments such as sprayers, hydraulic pumps and, well, generators. The PTO is low speed, so a PTO generator usually has a gearbox to step the speed up to the RPM needed to turn a generator. PTO's are pretty standardized and use a short driveshaft to couple the tractors PTO to the attachment. PTO generators are used where remote power is needed and a PTO-equipped vehicle is available. It saves having to buy and maintain another engine.
66 PTO horsepower and 72 engine horsepower.
21 hp engine and 17 hp pto
If you're talking the engine operating RPMs, 1000... 540 is idle speed. It's stressful on the engine to operate a PTO at that speed, plus running that low forms a carbon ridge at the top of the cylinders.