What are fans with BLDC motors?
What we call BLDC fans are identified with different acronyms such as BLDC (Brushless Direct Current), BLAC (Brushless Alternating Current) or ECM (Electrically Commutated Motor): we are always talking about the same technology, regardless of the terms convention. In a nutshell, the structure of the stator resembles that of AC induction motors, whose windings are constructed to produce the sinusoidal flow in the air gap. The rotor, on the other hand, uses permanent magnets, saving the induced currents to generate the flow: the rotating magnetic field is obtained by alternatively switching the stator windings in the same way as an asynchronous three-phase motor, but directly from the direct current and low voltage supply.
What would be the most suitable application field for BLDC direct current fans?
Thanks to the reducing energy consumption and low fan noise goals, brushless permanent magnet DC motors should be the obvious solution, especially in commercial refrigeration equipment. However, the old technologies are still well established, unlike other refrigeration sectors, such as the automotive sector, where a DC power supply is widespread, for all power segments.
Back in the “cold”, even the domestic appliance industries have replaced the old shielded poles fans in the domestic refrigerators since the ’90s, with obvious effects on the class of energy efficiency and silence in our houses.
Why is there a delay in the application of direct current BLDC fans in the commercial sector?
Above all, two aspects are involved in delaying the introduction of BLDC fans in the industrial and commercial world. The first is the duration of the life cycle of the device, entry ticket for new technologies that, although advantageous, must deal with the mechanical and electrical compatibility to existing architectures. A second reason is the relative low impact of the fans, compared to the total power absorbed by the machine that hosts them.
However, if we integrate over time the power absorbed by all the fans contained in the refrigerators of a supermarket or a refrigerated products warehouse, the result in terms of energy consumption are not irrelevant, indeed! The manufacturers have gradually begun to insert BLDC fans through hybrid solutions in EC technology, compatible with existing architectures, because they have an internal voltage converter.
The advantages of BLDC fans
The first advantages obtained relate to efficiency, reliability, durability, compactness, low maintenance requirements, simplicity in torque and speed control according to actual instant needs, but with an inevitable impact on costs.
Today, thanks to the diffusion of LED lighting in the display cases and in the refrigerated counters, low voltage is available in the appliance: this new scenario helps the definitive passage to 24V fans, in new projects, both in the ventilation of the condensing units and of evaporation, thus contributing to the birth of a new generation of fans able to overcome the same EC models, simpler, compact, lighter, reliable and economical. Furthermore, the offer of semiconductors dedicated to the control of the phases of this type of motors, as we have seen above, is always wider for all the power segments and with increasingly competitive cost levels.
To learn more about Fandis’ wide range of Esmeris compact axial and centrifugal fans, standard and customizable, visit our website fandis.it or leave a comment to this article. One of our technicians will answer you as soon as possible.
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