YS Tech USA and CTfanman discuss EC Motors 101

Last week I pulled a “fast one” on you guys, and introduced a new term on Twitter! Do you remember? Some of you called me wondering what’s up. Well, here’s a little more about EC Motors.

EC (or Electronically Commentated) motors are not entirely new. They have been around for a couple decades, but have mostly been used in the HVAC [Heating Ventilating Air Conditioning] industry. They are very popular in this application because of the high efficiencies they inherently have [some as high as in the 90’s per cent]. This is significant because the ordinary AC and/or DC motor often provide efficiencies in the 40’s per cent]. EC motors are so efficient because they use electronics to commentate or turn the motor.

But, I’m getting ahead of myself. You’re probably thinking, so what’s the difference with the EC Motor? If you were lucky like I was, way back in grade school, you had to make a [DC] motor for the Science fair. It looked like this.


If you look close you will see the ‘pink’ band just in front of the light blue windings. That is the commenter area. You will also notice the brushes resting on the commenter [+ / -], there are two brushes in this design. The electro-mechanical commentator directs the current to the correct winding, enabling rotation. It’s a simple design that has been around for hundreds of years. But, it has some inherent problems like wear of the brushes, heat generation; tend to be noisy and mostly restricted to a single operating speed.

 Now, enter the EC Motor. The electronically commentated motor has no brushes, does not generate heat and can be precisely controlled at most any speed desired. Sounds like some great advantages, don’t they? Well they are, and what makes it possible are the electronic components that are doing the electrical switching and control. EC motors look like this.

ECMotor cutaway

The part on the left has all the electronic components that do all the switching and motor control. The part on the right is motor. Yes, it looks a bit more complicated, but the electronic components are more reliable than the old brush design.

As you tech types may have already guessed, the EC Motor is a form of Brushless DC Motor, or BLDC. The electrical supply can be 120V or 240V AC and the components rectify the source to a DC, three-phase supply [actually, I think the number of phases depends on the particular design]. And I’m sure you have already figured out because of the electronic components, speed control is easy.

So what have we found out so far? EC Motors: run cooler and quieter [no RF noise because no brushes], can be controlled to most any speed, and is very efficient! Sounds like just the motor for these times!

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