EDITOR ’ S CHOICE EC MOTORS
AXAIR FANS
Motor Efficiency & the Schematic Structure of EC Motors
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 , 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 . 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 deepgroove 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 .
Advantages :
• High Efficiency
• Low power consumption
• Integrated monitoring function ( motor temperature , locked rotor and many more )
• Simple connection ( Plug & Play )
• Expanded functionality ( pressure control and many more )
• Compact design
• Speed Controllable
EC motors are ideal for integration into BMS 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 and 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 .
For further information , please visit www . axair-fans . co . uk
18 PECM Issue 53