In order to reduce the energy consumption of fans in ventilation and air conditioning applications, there is currently nothing to surpass modern EC technology. EC motors are more energy-efficient, durable and quiet, and can save up to 50% electricity usage.
EC stands for “electronically commutated” which means in power electronics, that a current flow passes from one branch to another in a well-defined manner.
Several power electronics components are required for an EC motor drive. Firstly, the alternating current must be converted into direct current by means of arectifier. A PFC (Power Factor Correction) circuit can be used to reduce the reactive power (impedance) entailing losses. It also allows variable input voltages. Theinverter, as the next stage, generates the voltage for the windings required to operate the EC motor. This develops magnetic poles in the stator, which interact with the permanent magnets in the rotor. These types of motor are also callBrushLessDirectCurrent motors.
When a BLDC motor rotates, each winding generates a voltage known as back Electromotive Force or back EMF, which opposes the main voltage supplied to the windings according to Lenz’s Law. The polarity of this back EMF is in opposite direction of the energized voltage.
The permanent magnets in the rotor are then attracted, in sequence, to the magnetic poles in the stator. Simultaneously, the rest of the stator windings are charged with the reverse polarity. These attraction and repulsion forces combine to achieve rotation and produce the optimal torque.
Below is an example of an electronically commutated three-phase BLDC motor, (but the full sequence can be found here):
Advantages :
Variable speed motors:
With the simplest of controls, the EC motor can be controlled precisely, stepless and down to 10% of its output without humming or stopping.
Conventional AC motors have to be controlled by an external frequency converter. This consumed a lot of power and also caused humming noises.
Energy saving:
EC motors consume up to 70% less electricity in ventilation systems. The rule of thumb is that the additional costs for an EC fan are paid off within 6 months through electricity savings.
High Performance :
EC fans build up a considerably higher pressure. This allows more air to be transported at lower costs
Other Advantages :
EC Fans are maintenance free and silent in part load
Stepless speed control allows pressure control, volume flow control and air quality control
There is no need for peripheral components like motor protection switch, thermal contact evaluation device, or phase control unit – all of these capabilites are managed inside the EC motor and automatically
