How to increase the maximum head of a submersible pump?

How to increase the maximum head of a submersible pump?

You can increase the maximum head of a submersible pump by bolting a higher horsepower motor to the pump. The better motor choice would be a three phase motor. A VFD can then be used to drive the pump and motor above original design speed thereby increasing the maximum head of the pump. Many drives accommodate single phase in and three phase out.

Many pump VFD or constant pressure drives are available to achieve your goal. The larger motor compensates for increased power demand. Most pump drives will increase speed until the maximum motor power limit is reached. Most commercially available pumps can tolerate 80 Hz. Be sure not to exceed maximum pump case pressure.

Doubling the motor horsepower is a combination most pump drives will accommodate. You can get a rough estimate of the modified pump’s maximum head by looking at the curve of the same brand and flow rating of your pump designed for the larger horsepower motor at normal speed. Your modified pump will likely make slightly more head.

Consideration when doing this are:

1. Maximum case pressure for the pump
2. Maximum speed for the pump
3. Noting possible increases in required net positive suction head
4. Motor maximum and minimum speed limits
5. Maximum thrust on motor thrust bearing
6. Reduced pump longevity
7. Possible increased motor cooling requirements