Energy Efficiency with EC Fans & Motors

Electronically Commutated technology combining both AC & DC voltages to deliver efficient fan power.

Energy Efficient Technology with EC Fans & Motors
 

Axair Fans has established long term partnerships with manufacturers ECOFIT s.a. (France) and ROSENBERG Gmbh (Germany) and are 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.

The non-rotating part of the motor (stator) has been extended to make room for an electronic PCB board which includes power transformation AC to DC, as well as the controls. The whole aspect is similar to a standard AC external rotor motor but with a slightly deeper base.

The results are reduced energy consumption producing an increased efficiency of 70% on current models (compared with 50% maximum in the AC single phase direct alternative). The electronically commutated motor can be offered with a number of options, such as Hall effect sensor or alarm output. The EC programming is also suitable for constant speed or constant pressure control.

DC motors already have low power consumption but if used in an AC application, the power needed to convert AC to DC, requires 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.

Permanent-magnet brushless DC motor within the rotor
The stator is driven by electronic switches (which replace the Carbon brushes), controlled by a microcontroller.
Electronic system (hall effect sensor or software is used to recognize the rotor position)
AC operated (230Volts Single phase or 380/480Volts 3phase, 50/60Hz)

Benefits

Energy savings : Minimum power consumption & better efficiency than AC equivalent.
Control : 100% speed controllable, not frequency dependant. Can be set-up for constant airflow or constant pressure applications, 0-10VDC or PWM control signal.
Low motor temperature : for longer lifetime than AC equivalent
Simplicity : Electronic & power transformation are completely integrated within the motor.
High performance : Speed can be driven up to 3600rpm, one EC fan replace multiple type of motors (2, 4 and 6 pole)
Easy connection : No complicated wiring and set-up with a Frequency Controller, EC fans have very little configuration.

Efficiency 

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 (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).