The two terms seem interchangeable and I can't find a strict definition for both, so what's the difference between them if there is any?


An impeller is the type of rotor found in a centrifugal pump, in fact another name for "centrifugal pumps" is "impeller pumps". Many different types of pump have rotors.

The pump "rotor" is simply a term the rotating components of the pump. Gear pumps, sliding vane pumps, swash-plate pumps and circumferential piston pumps all have rotors, but none of them have impellers

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  • $\begingroup$ But I have an inspection test plan for a centrifugal pump that requires a dynamic balance for both the rotor and the impeller how can that be? $\endgroup$ – Algo Apr 13 '16 at 4:21
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    $\begingroup$ Perhaps the plan means the rotor as the rotating components that are part of the pump such as the seal, shaft etc. and the impeller as solely the rotating component that acts on the water. I'd ask for clarification from the people who gave you the test plan, it sounds unclear. $\endgroup$ – DLS3141 Apr 13 '16 at 5:00
  • $\begingroup$ I found that API 610 defines rotor as "assembly of all the rotating parts of a centrifugal pump". $\endgroup$ – Algo Apr 13 '16 at 17:47

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