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Engineers have many options for motor selections, but most fans can be categorized into four types of motors:

  1. Alternating Current (AC)
  2. Direct Current (DC)
  3. Electronically Commutated (EC)
  4. Permanent Magnet Electronically Commutated (PMEC)

Alternating current (AC) and direct current (DC) have been the most common motors throughout the years. Recently, a newer, more efficient type has emerged called an EC motor. Facilities have been seeing massive benefits from using this EC technology. Now, there is even another development on EC motors to create the PMEC motor. We’ve seen many replacements from AC and DC motors to the new EC motors.

Here is a comparison of each motor type.

What are AC Motors?

AC motors are best for applications that need a fast and accurate response. They are powered by a series of coils controlled by an alternating current input voltage.

AC motors require higher input voltages to create a magnetic field. As a result, AC motors are less efficient than DC motors.

Advantages of AC Motors

  • Long-established technology
  • Replaceable and serviceable components
  • Abundant supply

Disadvantages of AC Motors

  • Low efficiency at part load
  • Requires maintenance
  • Requires VFD (Variable Frequency Drive)
  • Noisey
  • Average power and torque density

What are DC Motors?

DC stands for direct current, meaning the electrons flow in a single direction. To put it simply, DC is steady.

DC motors are highly efficient but still face specific losses. They lose efficiency from initial resistance in winding and friction.

Advantages of DC motors

  • More energy efficient than AC motors
  • Versatility with power

Disadvantages of DC motors

  • Require maintenance
  • Limited lifespan

What are EC Motors?

EC stands for “electronically commutated” motor, and it is one of the newer motor technology used in direct drive fans.

Advantages of EC motors

  • Highly efficient at part load
  • No maintenance required
  • No VFD required
  • Require less space lengthwise
  • Excellent power and torque density

Disadvantages of EC motors

  • Poor availability currently
  • Components can not be individually replaced

What are PMEC Motors?

PMEC stands for “permanent magnet electronically commutated” motor. PMEC motors combine synchronous reluctance and permanent magnet technologies for a wirelessly connected, sustainable solution.

Advantages of PMEC motors

  • Excellent full range efficiency
  • Smaller than traditional AC motors
  • Replaceable and serviceable components
  • Readily available Synchronous Reluctance technology, no rare earth materials required

Disadvantages of PMEC motors

  • Not as compact as conventional EC motors

Recap of Motor Types

While AC motors, and to some extent EC motors, have been the standard for commercial HVAC equipment for many years, PMEC motors have proven to be a solid choice for the future of AHUs. With better efficiency, less maintenance, and compact design, PMEC motors are an excellent choice.

Looking to upgrade your fan systems with PMEC motors? Contact Mainstream today to get started!