Paul Smith, Head of OEM at Axair Fans, discusses the benefits of EC motors and the effects of electric motor efficiency regulations.
Converting electrical energy to mechanical energy is not always very efficient, so the fact that one of the biggest energy consumers of any product is the electric motor isn’t all that surprising. The most common type of AC motor, the induction motor, has been around for over 100 years but with government regulations such as the electric motor efficiency regulations demanding International Efficiency of IE3 and above on motors 0.75kW and above, EC motors, or electronically commutated motors, are now the preferred choice in many fields and applications.
According to the International Energy Agency, electric motors account for approximately 45% of all global electricity usage and 75% of all industrial electricity usage. Efficiency is especially important in today’s climate, for reducing CO2 emissions but also for reducing the cost of a motor over its lifecycle.
Based on the new regulations that came into effect in July 2021, Premium efficiency motors (IE3) should be specified in all new installations, when purchasing spares, on major updates to existing processes and when replacing oversized or existing IE2 motors. When calculating the IE classification, the energy efficiency of an electric motor is calculated as the ratio of the mechanical output power to the electrical input power.
EC motors may seem complicated, but these motors make manufacturing processes more efficient, more reliable and allow them to perform better, with the biggest energy gains coming from the ability to speed control them.
Efficiency is the main reason for choosing EC motors over AC versions. With EC motors, the AC mains voltage is rectified in the commutation electronics reducing the losses internal to the motor. A downstream inverter provides the motor with the motor voltage depending on the position, like the principle of a frequency inverter.
On these energy-efficient motors, the intelligent EC commutation electronics decide how the motor phases in the stator are supplied with current (commutation) depending on the position, direction of rotation and speed specification. Permanent magnets generate the magnetic counter field in the rotor, and 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 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 greasing ensures maintenance-free and low-noise operation. The winding insulation corresponds to thermal class F.
Using intelligent electronics, a wide variety of control and regulating functions can be taken over by the EC motor depending on the area of application, variable speed control, pressure control, volume flow control, temperature control, air quality control as examples.
EC motors are ideal for integration into Building Management Systems systems such as Modbus, enabling maintenance engineers to monitor the status of individual fans and highlighting the need for retrofit or replacement. The Gen 3 motor from Rosenberg offers a range of benefits to the industrial fan market. It complements all backward-curved plug type impellers and modules, making them a technologically advanced and innovative product for air handling units, containment applications and data centres where energy efficiency is a core consideration of the air movement system.
