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Functional Principle

The Rosenberg EC-Motor


The Rosenberg EC-motor (EC = Electronically Commutated) is an inverter-fed synchronous motor with permanent magnets in external rotor construction.

The motor position is dependent upon voltage supplied via an inverter module (similar to the principle of a frequency inverter). The EC commutation electronics are different from a frequency inverter in that they decide how the motor phases in the stator are supplied with current (commutation) depending on position, rotation direction and default.  Permanent magnets in the rotor produce a magnetic field which is required for full load production. A high efficiency, low noise, and continuous motor speed control is possible with this. An assembly flange on the rotor is used for impeller assembly. Depending on the motor type, a terminal box is avaible with cable screw connections or connection cable for easy and quick connection.
Depending on the application area is possible to adopt further control functions (e.g. constant pressure control, volume flow control, temperature control, air quality control)


Fans with EC-Drives


Rosenberg offers a plethora of energy efficient fans with EC-drives in the area of standard fans, fans for OEM-applications, and fans for use in ventilation units. EC-fans are utilized everywhere where economical energy usage and simple control are required based on the actual ventilation needs. The integrated electronics sets the EC-fan for optimal operation every time. All that is needed is a control signal.

Open Loop

In operating mode “open loop “the speed of the fan can be sleeplessly adjusted through a 0-10 V or 4-20 mA set point input. EC-fans with integrated electronics are speed controllable 0...100% of the nominal speed.


Closed Loop

In operating mode “closed loop “the EC-fan compares the nominal value with the measured actual value and adjusts the speed accordingly to the set requirements. The measured values (pressure, air flow volume, temperature, CO2 …) must be present as an electrical signal 0-10 V or 4-20 mA.

Bus operation

In operating mode “bus “the EC-fan can be integrated into a bus system through an RS-485 interface.


With the free Rosenberg software ECParam, changes to settings of the EC-fan can be made using a USB-to-RS485 adapter. Current operating conditions can also be read-out (Changing the operating mode, setting a specific minimum or maximum speed, and much more)

The following fan types are available with EC-drives:

Furthermore, due to their outstanding properties, EC-fans are generally used in our energy recovery units. Depending on the air volume and application our Airbox air handling units are also equipped with energy efficient EC-fans.


Calculation Examples


Rosenberg EC-fans have high energy saving potential under full load and especially under partial load. The efficiency losses are significantly lower than with conventional AC-motors at the same air flow. The improved energy efficiency results in fewer CO2 emissions. In addition, there are lower investment costs for speed control of the fan. A control transformer, VFD or phase angle controller are not necessary. All necessary components are already contained in the EC-motor electronics. Modern EC-technology from Rosenberg is not only easy on the wallet, but also on the environment.
Representative calculation examples:


Energy saving potential of EC Centrifugal fans, Size 560



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