As the angle increases, it becomes increasingly harder on the driving and driven pieces of equipment, too.
Believe it or not, output rpm is not constant when the angle between the two shafts is other than zero. Throughout one full turn of rotation, the output shaft lags, then leads, the input shaft in rotational speed. Whatever is attached to this shaft experiences this same, very rapid, change of speed. If the driven piece of equipment has a lot of intertia, (like a pull-behind rotary cutter, in a turn) it can really work the pto drive train in the tractor.
Believe it or not, output rpm is not constant when the angle between the two shafts is other than zero. Throughout one full turn of rotation, the output shaft lags, then leads, the input shaft in rotational speed. Whatever is attached to this shaft experiences this same, very rapid, change of speed. If the driven piece of equipment has a lot of intertia, (like a pull-behind rotary cutter, in a turn) it can really work the pto drive train in the tractor.