EC Technology & EC Fans

Understand how Electronically Commutated technology combines both AC & DC voltages to deliver efficient fan power.


EC Technology & EC Fans

Axair Fans has established long term partnerships with manufacturers ECOFIT s.a. (France) and ROSENBERG Gmbh (Germany), and are now able to offer Energy Efficient EC fans and air movement products. Both Ecofit & Rosenberg develop and manufacture their own motors and fans. The Ecofit EC range use motors from 65 up to 113Wa, the Rosenberg range use motors from 1.1 up to 3.4Kwa motors.

What is EC technology?

EC Technology stands for Electronically Commutated and combines AC and DC voltages, which is essentially a fan with a brushless DC motor, bringing the best of both technologies: the motor runs on a DC voltage, but with a normal AC supply. DC motors already have low power consumption but if used in an AC application, the power needed converting AC to DC, using a bulky, inefficient transformer. The EC motor incorporates voltage transformation within the motor. The non-rotating part of the motor (stator) is extended to make room for an electronic PCB board which includes power transformation AC to DC, as well as the controls.

All the features of the external rotor motor are kept, including compact assembly, easy speed controllability, efficiency and characteristics.


EC Motor – Principle

With an EC motor the electronic circuitry stands in lieu of the traditional mechanical commutation meaning the right amount is being supplied in the right direction at exactly the right time providing precise motor control.



EC technology motors have a near flat efficiency curve which barely varies across the speed range. A range of which is not limited by synchronous speeds or susceptible to voltage variations like its AC counterpart. Its AC equivalent will operate at a precise point on the curve which equates to its maximum efficiency, either side of this point and the efficiency diminishes.

Typical AC motors have losses in terms of power consumption (copper + iron losses), slippage and frictional losses (mechanical power). EC motor have no slippage losses, reducing losses and increasing efficiency.

By comparing 2 backward curved centrifugal impellers, one in AC and the other in EC.

The Rosenberg EC Motor

The Rosenberg EC motor (EC = electronically commutated) is an inverter-fed synchronous motor with permanent magnets in an external rotor design. The AC mains voltage is rectified by the commutation electronics of the EC motor. A downstream inverter provides the motor with the motor voltage depending on the load, similar to the principle of a frequency inverter. In conjunction , all parameters of the commutation electronics and  are optimally matched to each other. The intelligent EC commutation electronics decide how the motor windings in the stator are supplied with current (commutation) depending on the position of the motor, direction of rotation and speed set point. Permanent magnets generate the magnetic counterfield in the rotor, the torque required for rotation is generated from the interaction of the stator and rotor fields. A mounting flange on the rotor is used for stable impeller mounting. The simple and quick electrical connection is made either via a terminal box with cable glands or a connection cable, depending on the motor series. The use of deep-groove ball bearings closed on both sides with specially matched grease ensures maintenance-free and low-noise operation. The winding insulation meets thermal class F. Through the use of intelligent electronics, a wide variety of control and regulating functions can be taken by the EC motor depending on the area of application (infinitely variable speed control, pressure control, volume flow control, temperature control, air quality control).


✔️ High Efficiency

✔️ Low power consumption

✔️ Integrated monitoring function (motor temperature, locked rotor and many more)

✔️ Simple connection (Plug & Play)

✔️ Expanded functionality (pressure control a.s.o.)

✔️ Compact design

EC Motor

Model Fan/motor type Supply Motor power Speed
DKHR 315-2SW-098 AC 3 phase fan 2 pole motor 400Volts 50Hz 1.52Kwa 2750rpm
GKHR 315-CIW.098 EC 3phase fan 380/480Volts 50/60Hz 1.41Kwa 2950rpm


ModelPoint 1 - 2603m³/h at 900 PaPoint 2 - 2000mm³/h at 166PaPoint 3 - 3300mm³/h at 450Pa
DKHR 315-2SW.098.6FA (Fan power)Power : 1.42kWPower : 0.62 kWPower : 1.41 kW
Efficiency : 37.5%Efficiency : 14%Efficiency : 28%
GKHR 315-CIW.098.5FA (Total power)Power : 1.33 kWPower : 0.27 kWPower : 1.04 kW
Efficiency : 49.6%Efficiency : 38%Efficiency : 45%

Energy savings with EC fans

Let’s assume a laminar flow workstation requiring 13200m³/h at 450Pa. This requires 4 off Ø315 backward curved fans. Now let us assume that this workstation operates for 50 weeks of the year and for 8 hours per day at full speed. During non working hours to maintain the work area, the fans are run at roughly half the airflow.

Let’s compare the power consumed :

AC fan 2800hrs @ 4 x 1.41kW = 5.64kW 15,792 kWh
5600hrs @ 4 x 0.62kW = 2.48kW 13,888 kWh
Total A29,680 kWh
EC fan 2800 hrs @ 4 x 1.04kW = 4.16kW 11,648 kWh
5600 hrs @ 4 x 0.27kW = 1.08kW 6,048 kWh
Total B17,696 kWh
A minus B11,984kWh saved with the EC fan

Additional Functions


References available

EC fans from manufacturer Ecofit ecofit

Backward curved motorised impeller. Available in diameter Ø192, 220 & 225.
Forward curved centrifugal fan, Single inlet
Forward curved centrifugal fan, Single inlet. Available in Ø160. Constant pressure or airflow configuration available.
Forward curved centrifugal fan, Double inlet
Forward curved centrifugal fan, Double inlet.Available in Ø160. Constant pressure or airflow configuration available.

EC fans from manufacturer Rosenberg rosenberg

Backward curved centrifugal motorised impeller. Available in Ø280, 315, 355, 400, 450, 500, 560 & 630. Can be used in the ECFanGrid.
Backward curved centrifugal fan – Single inlet
Backward curved centrifugal fan – Single inlet. Available in Ø280, 315, 355, 400, 450, 500, 560 & 630.
Axial fans – Available in Ø630, 710, 800, 900 & 1000. Several configuration available.
UNOBOX extraction / Ventilation units. Available in 4 sizes, Fitted with motorised impellers Ø355, 400, 450, 500, 560 & 630.
Rectangular In-Line Duct fans. Available in 4 sizes, Fitted with motorised impellers Ø355, 400, 450, 500 & 560.
Roof fans with vertical discharge. Available in 3 sizes, Fitted with motorised impellers Ø355, 400, 450, 500, 560 & 630.

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