How to calculate the size of a motor to pump continuosly @ 500rpm? delivers flow of 0.05 m3/s pressure difference of 350 kpa overall efficiency of 70 % efficiency of reducer is 95 % assume the centrifugal pump has a approx quadratic torque - speed characteristic: would appreciate a helping hand for a formula to work with ? i have tried to research the question for a solution or a formula to work with but to no avail and also - what is meant by quadratic/ torque speed ? thanks
is this correct ? Water power is a simple way to equate the pump to mechanical power based on mass, distance lifted against gravity and time. Power_W = (Mass_kg x Gravity_m/s/s x Height_m) / time_s Where: Gravity is 9.81m/s/s Mass is 0.05 * 1000kg for one cubic meter of water Height (head) is 35.7m for 350kPa. Time is 1s, for flow per second. Now increase the power for the losses = Power_W / (0.7 * 0.95) This is the mechanical power from the motor. You have stated the speed is constant @ 500 rpm, so torque - speed is not needed. The torque from the motor (used by the pump) can be calculated as: torque_N.m = (60000 * Power_KW) / (2pi * RPM) cheers !!!
Power is equal to volumetric flow times pressure. All you need is to account for losses and to get your units in order.