How EC Motors Work

In this podcast episode, Bryan and Chris Mohalley from Regal Beloit discuss EC motors. They also describe ECM applications and how those motors work.

EC motors (ECMs or “ECM motors”) are electronically commutated motors. These motors are generally three-phase AC motors operated by a drive; that drive is a combination of an AC-to-DC converter, microprocessor, and frequency drive. So, the frequency delivered to the motor is generated electronically.

When it comes to inputs, the ECM works like a printer. One input provides power (from the wall to the printer). The other cable tells the printer what to do and when to do it (from the computer to the printer). An ECM will have a line voltage connection and a constant 24v communication input. Constant-torque ECMs work like PSC motors in the way they use control taps; other ECMs may use DIP switches.

ECMs are direct-drive motors that differ from PSCs because they don't have a capacitor. EC motors also have a permanent magnet, which can affect diagnosis if you rarely come across indexing.

AC motors use magnetism; when you pass energy through the stator coil, the coil creates an invisible magnetic field, which then induces a magnetic field into the rotor. When the rotor picks up a magnetic effect, it starts to spin. EC motors have that magnetic effect in their magnets.

Chris and Bryan also discuss:

  • Regal Beloit's history and brands
  • Effectiveness of metaphors and acronyms in our industry
  • Constant-torque ECM vs. variable-speed motor
  • Motor modules
  • Changes to the ECM design over time
  • ECM manufacturers
  • Three-phase power and controls
  • Reading ohms
  • Glued-on vs. slotted magnets
  • RPM and the effects of poles and frequency of power delivered

For more resources for EC motors, check out

Learn more about Refrigeration Technologies HERE.

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Ken Darin
Ken Darin
7/10/21 at 02:58 PM

Great Job Chris!!!! See ya in a couple weeks and Bryan let’s golf soon! I’ll stop by your office this week.



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