Torque and Hydraulic Motors

You need as well the displacement of the motor in units of volume/revolution.

The theoretical torque is V/(2π)*p. The units must be coherent. Speed is not important for hydrostatic torque as for centrifugal pumps. Speed affects only the efficiency i.e. at higher speed the friction loses are more important.

If you know the motor type in the manufacturer's catalogue you find (normally) the displacement.

M= ΔP .Vh/2.Π

Pump M= drive torque

Motor M=driven torque(with out η ).

ΔP = Pressure drop between outlet and inlet ,of the pump ,inlet and outlet of the motor

Vh =geometric stroke volume

I think the above equation is general for hydraulic pump and motor,and the effect of changing the R.P.M, is accompained by change in pressure,it means pressure changes accoredinly ,with speed change

pressure does change as a function of resistance variation versus speed not the speed is the parameter but the way the process reacts to speed changes.

If to speak about drives to valves reactor, I do not advise this change.

Let's lose for the major advantages at failure:

-time closing-opening of the valve,

-reliability of a drive,

-independence of an electric line,

-manual management of the crane.

My experience is those.

Success to you.

I am sory but I do not understand your comment. Was it anywhere mentionned a valve? I did not see it, As you know in some reactors in order to have an uniform result there are mixers and during reaction the viscosity of the mass evoluates so that the torque capability is very important for the process efficiency. If the mixer does not woek properly yhen the charge is not uniform and can be a waste. For valves command hydraulics have the advantge of the accumulator which can be used in case of emegency shut down even if curent supply fails. It is the so called fail safe principle but as far as look at the question there is never mentionned such a situation

Excuse, but I wrote only about drives to valves.

If to speak about drives to valves reactor, I do not advise this change.

Let's lose for the major advantages at failure:

-time closing-opening of the valve,

-reliability of a drive,

-independence of an electric line,

-manual management of the valve.

My experience is those.

Success to you

If you know the torque with the hydraulic motor it will not change with the electric motor unless the speed is different. I am guessing they are either using a plotted curve for the hydraulic motor based on pressure and speed. That same pressure and speed curve would still apply. You can obtain a graph from the motor manufacturer that will give you speed, torque, current, and HP for the motor under load at a given voltage. Just convert it all to HP. The only difference will be actual efficiency. But if you are measuring actual pressure and flow and rpm you will be able to factor out the efficiency of the existing hydraulic motor installation.