Dec 11, 2023
Electronically Commutated Motor Fundamentals and Benefits

With rising energy costs and pressure to minimize downtime, finding highly efficient and reliable commercial kitchen ventilation equipment is vital to ensure success and longevity for today's foodservice operators. One component in commercial kitchen ventilation that operators can explore more efficient options for is exhaust fans, specifically related to motor solutions that power exhaust fans. The electronically commutated (EC) motor is one solution offering improved reliability and proficiency that traditional motor options cannot provide.

EC motors have been around for more than 30 years but have gained increasing popularity in kitchen ventilation applications within the last decade. EC motors commutate, regulate, or reverse alternating current direction to create a direct current through electronic circuitry. This versatility allows for increased efficiency and greater speed control.


A few key features drive EC motor productivity. For example, every motor type has two magnetic fields. One field is in the rotor and the other is in the stator. Some motors require electricity for both magnetic fields. EC motors achieve efficiency by using electricity for only one magnetic field because of the EC's use of a permanent magnet rotor. Partial load conditions are a challenge for most motors. However, an EC motor like Greenheck's Vari-Green® offers an integral control board. The control board monitors the load continuously to adjust energy consumption, increasing or reducing it as needed. This monitoring results in highly efficient energy use in partial load conditions. Induction motors have no such capability without additional equipment.

Additional Features of an EC Motor

The Greenheck Vari-Green® Motor offers a built-in variable speed drive, eliminating the need for an external VFD which is a great advantage over other EC motor providers that require an external device to regulate the fan speed.

EC motors offer many other advantages that include:

  • No drive loss
  • Minimal maintenance
  • Less noise/vibration
  • Reduced fan size/weight

Motor Sizes

EC motor sizes and offerings vary by manufacturer. As a Greenheck Group company, Accurex offers EC motors in sizes ranging from 1/15 hp to 2 hp in a single-phase version and three-phase EC motors from 1 hp up to 10 hp.


Reliability remains an important part of exhaust fan applications especially as demand for better indoor air quality increases. Greenheck's Vari-Green motor delivers a low failure rate of less than one percent. This is due to the capability of running at a lower temperature at lower speeds - lower temperature leads to longer product life. Still, there is a misconception in the industry that EC motors could overheat while running at lower speeds. The truth is that EC motors use permanent magnet technology and do not get hot when you slow them down.


When comparing costs between EC motors and traditional motor options, there is more to consider than initial upfront costs. For example, an EC motor can have a first cost that is very competitive compared to a belt drive fan. The difference frequently is plus or minus 10% of a belt drive fan. A direct drive fan with a standard motor may cost less initially but remember that an external device is also needed to adjust speed, such as a VFD reference earlier. In addition to requiring less external additional parts to complete the system, the lower operating cost of an EC motor is a true differentiator. Vari-Green EC motors can reduce operating costs by between 30% and 50% depending on the operating conditions. Functions including a turndown capability (80% of the maximum RPM) allow the Vari-Green motor to control speeds while using less energy without requiring an external device.

EC motors used in exhaust fans continue to grow as new optimizations and sizes become available. To learn more about how our Greenheck Vari-Green EC motor solution can work for you, connect now with a local Accurex expert.