The 3 types of Pumps
Single Speed Pool Pumps correlates to the max operating speed of variable speed pumps. These pumps use an induction motor that runs at a constant speed of 2850 RPM. They can be flooded suction pumps, meaning they are placed below the water line using gravity to keep the pump primed, or they can be self-priming, which is the typical in-ground installation.
Variable Speed Pool Pumps adjust the flow rate of water through the circulation system, while single speed pumps only have one speed. These pumps are equipped with durable thermoplastic housing and ergonomic lid with Lexan see-through cover for easy basket inspection.
Dual Speed Pool Pumps are in the same electrical category as single speed pumps, but the main difference is that they run on a "High Speed and a "Low Speed". Dual speed pumps also cost a bit more than the single speed pumps as far as upfront cost is concerned. But if you operate it properly you can have significant energy savings.