What is the difference between an AC and EC motor?
In HVAC business, an induction motor is often referred to as ‘AC motor’.
These motor types have a stator winding to generate the required magnetic field to generate torque. AC motors (and certainly induction motors) are relatively cheap and have a simple construction, compared to DC motors. At the other hand, DC motors offer a very high energy efficiency.
Brushless DC motors are also known as EC motors or Electronically Commutated motors. They are synchronous DC motors, powered by a DC electric source via an integrated fan speed controller which produces an AC electric signal to drive the motor. The integrated controller uses a DC current switched on and off at high frequency for voltage modulation and passes it through three or more non-adjacent windings.
An EC motor can be seen as an AC motor with integrated fan speed controller.
This means that an EC motor requires an indication of the desired fan speed. Many EC motors can be controlled via an analogue 0-10 VDC or PWM signal. More and more EC motors feature Modbus RTU communication. The advantage is that they cannot only be controlled via Modbus RTU, but all the motor parameters (Rpm, consumed power, motor status, motor temperature, etc.) are also available via Modbus RTU.