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 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.
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)
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.
EC motors have a near flat efficiency curve which barely varies across the speed rang. A range of which is not limited by synchronous speeds or susceptible to voltage variations liek 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.
AC 3 phase fan 2 pole motor
EC 3phase fan
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Point 1 - 2603m³/h at 900 Pa
Point 2 - 2000mm³/h at 166Pa
Point 3 - 3300mm³/h at 450Pa
DKHR 315-2SW.098.6FA (Fan power)
Power : 1.42kW
Power : 0.62 kW
Power : 1.41 kW
Efficiency : 37.5%
Efficiency : 14%
Efficiency : 28%
GKHR 315-CIW.098.5FA (Total power)
Power : 1.33 kW
Power : 0.27 kW
Power : 1.04 kW
Efficiency : 49.6%
Efficiency : 38%
Efficiency : 45%
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The EC fan can rotate at a higher speed (2950rpm) than the AC (2750rpm) with a smaller motor than the AC fan (2.41 instead of 1.52Kwa)
The data for the AC fan is the consumed fan power and excludes losses from any inverter or controller necessary to control the fan.
The EC fan does not require any inverter or speed controller
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 :
2800hrs @ 4 x 1.41kW = 5.64kW
5600hrs @ 4 x 0.62kW = 2.48kW
2800 hrs @ 4 x 1.04kW = 4.16kW
5600 hrs @ 4 x 0.27kW = 1.08kW
A minus B
11,984kWh saved with the EC fan
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Constant pressure : Used in conjunction with a pressure sensor, the fan maintains the same pressure at varying airflow (ideal for ducted applications). Operates with forward curved centrifugal fans without pressure sensor and with backward curved motorised impellers with pressure sensor (Available on Ecofit fans).
Constant airflow : The fan maintains the same airflow at varying pressure (ideal for filtered applications) (Available on Ecofit fans).
0-10VDC / PWM output : EC motors can be controlled by a simple, standard 10kOhms potentiometer on the integrated 0-10VDC output (Available on both Ecofit & Rosenberg fans)
Hall effect : A tachometric output is available, which can be used for an optional alarm relay (Available on both Ecofit & Rosenberg fans)
Pressure control : A pressure sensor can be connected directly to the Electronic of the EC motor. The pressure control is made by the integrated electronics. No additional control unit is needed. (Rosenberg Versions only)
Master/Slave : This system is used when several fans are used together within a single application. The main fan (Master) is individually pressure controlled. The other fans (slaves) are then speed controlled by the Master fan : Slave Fans are always at the speed of the master fan (Rosenberg Versions only).