The Variable Speed Pump motor components explained;
Typical variable speed (VS) motors have three major components: 1) the motor 2) the drive that is bolted on to the motor 3) the controller that sits on the drive. The drive provides electrical in DC 3 phase to the motor and contains the circuit boards used to control the motor. The controller has a panel of buttons and a display that allow for user input to program time and speed commands to the drive. In some cases, the controller can be taken off the drive and mounted on a wall for easier accessibility to the panel. The Totally Enclosed Fan Cooled (TEFC) motors keep water and bugs out which prolongs their life to three times the life of a standard induction motor. The variable speed motor can be totally enclosed because of the permanent magnet technology which allows these motors to run much cooler and quieter than the standard induction motors. At 1800 Rpm (about half the rpm of a standard induction motor) the pump is almost silent and yet capable of keeping most pools clean and sanitized.
Overview of Variable Speed Motor Features;
Variable speed motors on the market today have common features. Energy savings up to 85% in operational costs with an average savings of 75% depending on your pool features and location. Their THP (Total Horse Power) is in a range of 1.65 to 3.45 HP and most are wired for 240V and run between 600 and 3450 RPM… They have integrated timers mounted on the top of the motor that can be programmed for 4- 8 different speeds in 4-8 different time slots. Variable speed motors use permanent magnets technology in place of coiled copper wire used in standard induction single speed motors. TEFC motors run much quieter at full speed. At the lower speed, you can hardly hear them at all. The induction motor runs at one or two speeds, it is noisy and creates a lot of heat. Heat is a killer of motor life spans.
Why pay more for these Variable Speed motors?
The basic law of physics says that if you reduce the RPM of a motor by half, you reduce the energy required to move that water to one eighth the full speed energy. If it costs $2.20 a day to run a single speed motor for eight hours, it would only cost $0.28 to run a variable speed motor for the same amount of time at half speed. Running a variable speed motor at half speed for 16 hours would cost $0.56 / day. That’s savings of 75% . This savings allows you to run the pump longer for less money which in the end results in a crystal clear pool and a savings of $231.00 ($1.65 savings x 140 days in an average season) each season. Cost savings depend on what you pay per KW/HR, the higher the cost the more you save. Check out energy star pumps for a comparison.
How much energy do VS pumps save you:
How much money can you save with a variable speed pool pump? According to the US Department of Energy, an average swimming pool holds 25,000 gallons of water and has a suggested turnover rate of 24 hours.
If your running this pool with a standard, single-speed pool pump with a flow rate of 66 gallons per minute (gpm). It would take about 6.3 hours to turn over the entire pool. (25,000 gallons / 66 gpm) /60 minutes = 6.3 hours
If that pump uses 2,000 watts per hour, it will consume 12,600 watt-hours or 12.6 kWh every day. 6.3 hours x 2,000 watts = 12,600 watt hours (12.6 kWh)
If you switch to a variable speed pump. Because of the Pump Affinity Law, a slower flow rate will use less energy even if it means the pump has to run for longer. A variable speed pump set at a flow rate of 22 gpm will consume 116 watts per hour, and turn the pool over in 19 hours. (25,000 gallons / 22 gpm) /60 minutes = 19 hours
The variable speed pump will only use 2.2 kWh of electricity to do so, compared to the 12.6 kWh it took the single speed pump to turn over the pool, even though it has to run for much longer. 19 hours x 116 watts = 2,200 watt hours (2.2 kWh)
That works out to a savings of 10.4 kWh per day, or approximately 3,796 kWh per year! The average residential electricity rate in Illinois is 14 cents per kWh as of January 2025, which means you could save $531.50 year with a variable speed pool pump!
Variable speed pumps and filtration:
Variable Speed motors can be run 24/7 at a low cost add to that a cartridge filter and Salt generator for even more efficiency to your pool. The ideal way to run water through any filter is at low pressure and volume. This will increase the number of particles filtered out. For vacuuming the speed of the motor will need to be increased to give your vacuum better suction, but this usually occurs only 1-2 per week. On sand filters and DE, the Variable speed motor will also need to run on high to provide the proper flow to clean the filter.
Our American made Speck and Pentair VS pumps combined with a salt generator and cartridge filtration are designed to give you maximum energy savings and low maintenance. These variable speed pump is Energy Star rated. Visit Century motors for more information on Variable Speed motors and Com Ed for possible rebates!
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