The right speed for an agricultural irrigation pump is the pump's own design speed, and the motor is chosen to match it. If the pump nameplate says 2,900 rpm you need a 2-pole (3,000 rpm class) motor; if it says 1,450 rpm, a 4-pole (1,500 rpm class) motor.

Which pump runs at which speed?

In systems needing high pressure, such as drip and sprinkler lines, multistage pumps or pumps with small impellers usually run around 3,000 rpm. Pumps lifting large volumes from a canal or pond to a low height mostly run at 1,500 rpm. A low-speed pump does the same job with a larger impeller; in sandy or silty water, impeller and seal wear progresses more slowly.

Old belt-driven pumps

On pumps converted from a tractor PTO to an electric motor, or driven by belt, the pump speed is the motor speed multiplied by the ratio of the pulley diameters. If you want to keep the pulleys when replacing the motor, choose the same number of poles as the old motor; if you choose a different speed, have the pulley ratio recalculated.

Running all season

  • For a pump running long hours every day in the irrigation season, the efficiency class directly affects operating cost; IE3, IE4 and IE5 options can be compared from this angle.
  • If the flow has to follow the well or tank level, an inverter can be considered.
  • In open fields, even an IP55 motor should be kept under a shelter with its ventilation clear.

We explain the difference between 1,500 and 3,000 rpm with examples in the article on speed selection for an irrigation centrifugal pump. For other pump types, see the pump electric motors page.

Models are on the irrigation pump motor page. Send a photo of your pump's nameplate, and the old motor's if available, via WhatsApp; we will check speed and power compatibility and tell you the equivalent in stock.