Is it possible to use a motor as a pump? Suppose I knew the rated output rpm's, and I spun it at that, used a gravity feed oil system, would it pump at it's input pressure?
I believe there are more differences that that, for instance, the ports on a pump are usually different. Some pumps can be used as motors, but you don't see many people doing that.
Are you talking about just gear pumps, vane pumps, or all pumps.
Some pumps can be used as motors/ vise versa. I have found that those are primarily gear pumps, but not every one can be used as both. I have 2 gear pumps that can be used also as motors. You need to be sure or you will burn out some equipment fairly quickly.
I guess i should have clarified some info... MOST gear, vain and piston pumps can be used as a motor, check with the manufacture to see what parts and modifications are required, some have no mods required, some need new high pressure seals and some require seals and internal mods.
Check with Char-lynn,parker,danfoss etc. to see what GPM is required for what RPM and Torque ratings.
As far as porting, both the pumps and motors use ORB,pipe or flange type.
A Bi directional motor has same size ports on both sides, even if all shaft seal issues can get solved, I would not recommend using that motor as a pump, for the risk of cavitation....a pump need larger inlet port than pressure side port.....
Also, some vane most(/all?) pumps do not have springs behind the vanes, and cant get pressureized....in a vane pump, the rotor with the vanes need to rotate, and give vanes centrifugal force to seal the pump....there are other issues to w vane pumps....Dont expect it to be that easy to use "every" pump as a motor and v v.....