Hydralic Motor Question

[Tim/South]

How does one figure how many RPM's a hydraulic motor will turn?

I am going to adapt a brush cutter for a BobCat and can not find any numbers or a formula to let me know if the motors I have will turn enough RPM's.

I bought some new motors at an auction. They are large compared to what a normal hydraulic cutter has. That got me to wondering if I would need more flow than my machine is capable of putting out.

I am also adapting the post hole auger but am not overly concerned about the speed on that since down pressure option is more.

Any ideas?

[D._Frederick]

You need to know two things : Displacement of the motor and output of you pump. convert both to cubic inches and the pump output to cubic inches per minute.  Divide the figure you get for the pump by the figure you get for the motor and you will end up with revs/min.