09/08/2020

Permanent Magnet Motors: Slow your Fans to Speed up Savings

What are Permanent Magnet (PM) Motors?

Permanent magnet motors are ac motors that have magnets attached to or embedded into the surface of the motor’s rotor. Instead of using windings on its rotor, a PM motor uses these permanent magnets, meaning the rotor is magnetized already.

These magnets are then able to generate a constant magnetic flux instead of requiring the stator field to generate one, similar to an induction motor.

 Advantages of PM Motors

 PM motors have multiple advantages for farms of all sizes in any season. Including: 

  • Precise and Consistent Variable Speed Control – Regardless of environmental factors such as static pressure and wind, the motor will run at a constant speed. More or less power will be applied to the motor so outside factors do not compromise set speeds.

  • Maintenance Free – Just set it and forget it! Direct Drive PM motors don’t have belts, pulleys, tensioners, or gears. Don’t spend time changing belts or lubricating bearings.

  • Increased Motor Longevity – Because of the PM motor’s lack of moving parts, there are a lot fewer parts to wear over time. The motor runs cool, also increasing longevity.

  • Fewer Fans – With speed control capabilities, you won’t have to have a combination of fan sizes to operate minimum winter or maximum summer ventilation. The PM motor allows you to do both with the same fan. Purchasing smaller fans is not needed.

 Energy Efficient – Why Slowing the Motor Down Increases Energy Efficiency

Power consumption required to spin a fan changes by the cube (X³) as the speed is increased or decreased. In a perfect world, when decreasing the speed by 10%, you decrease the power consumption by 30%. However, there are losses based on external factors. For J&D’s PM motor, you will see a decrease of power usage of 26%.

PM motor fans are great for minimum winter ventilation. A farmer could run a few fans at 60% power and see their CFM/Watt drastically increase because of the cube root rule.

PM motors are game-changers for facilities of all sizes.