text: <s>[INST] 3600 RPM Motor on VFD? I have an application where I need to run a pump at 2400 RPM to achieve the desired pressure. I currently have a 20HP 1800 RPM motor running at 70 Hz. (2000 RPM)I cannot increase the speed (Hz) more or my drive trips on OL.I am looking at increasing the motor HP and Drive size and/or changing the motor to 3600 RPM.Has anyone ran a 3600 RPM motor on a Powerflex at 45Hz or so? We have considered changing the pump, but that requires a larger motor, Powerflex Drive and cable anyway.I am looking at the above approach to avoid the pump purchase. Any Thoughts? [/INST] Cygnusx1, when a motor goes above it's base speed, in your case 1800RPM, the torque will begin to drop off as the speed is increased. See the formula and torque curve below:HP = TN 63,000Where, T = Torque (in-lb) N = Speed (RPM) As the motor speed goes up (N), the torque has to go down to maintain constant HP. To go to 2400RPM, you will have to run at 80Hz. Your torque will drop off considerably. If you go to a 3600RPM motor, you will be in the constant torque area of the torque curve for you full range and you will be running at 40Hz. If you use an inverter duty motor you shouldn't have a problem. \\n </s>