Pump and Motor Inertia Calculator

If the motor and pump inertia values are not available, you can use this calculator to determine an estimate by entering values for the following attributes:

Brake Horsepower at the BEP: The brake horsepower in kilowatts at the pump’s BEP (best efficiency point).
Rotational Speed: The rotational speed of the pump in rpm.

When you click the OK button, the calculated inertia value will be automatically populated in the Inertia (Pump and Motor) field on the HAMMER CONNECT tab of the Pump Definition dialog.

The calculator uses the following empirical relation developed by Thorley

where:	P is the brake horsepower in kilowatts at the BEP
	N is the rotational speed in rpm

If uncertainty in this parameter is a concern, several simulations should be run to assess the sensitivity of the results to changes in inertia.