Power Measurements

"Can mesuring required power (kw) for driving pump ,from mesuring electrical power parameters of cupleted motor ?" Yes

"why? for proofing electrical consumption." If the motors are the same you should get a close estimate of the kw usage.

The power required for any fluid mover is the volumetric flowrate multiplied by the pressure rise divided by the efficiency.

Pump HP = {(Specific gravity of the fluid being pumped x Head x Flow rate)

/ (K x Efficiency of the pump)

The constant 'K' depnds upon the units of flow rate, head & specific gravity.

From this you can cross check the power required for doing the required pumping work. Divide this by the motor efficiency, that will give you the motor HP.

The motor nameplate HP is its rated output mechanical power so there's no need to divide by motor efficiency, its already taken into account.

Just take the pump required power and select the motor accordingly.