Fans in electronics - quality comes at a price
The fans used in electronic devices are products of which more and more is being required. A good fan must provide excellent mechanical and environmental durability, a high degree of cooling efficiency and low noise, small size and low power consumption. Most of these components are unable to provide all of these features at a high level at the same time, hence those offered by manufacturers include hundreds of models from which to choose in order to achieve one’s goals.
We invite you to read the following review of those offered by two major fan manufacturers trying to meet the demands of designers and convince us that cooling by means of a fan does not necessarily mean problems.
AC fans by the Maxair company
Maxair is a Far Eastern manufacturer of fans, which specializes in the production of versions intended for an AC voltage supply. Such versions are used for cooling larger systems, industrial installations, ICT (information and communications technology) cabinets and power electronic devices, where there exists a need for efficient ventilation devices while maintaining low noise levels.
In a single product Maxair fans combine quality, excellent technical parameters at a reasonable price, significantly lower than many equivalent solutions of this type available on the market. All fans offered by the company meet the requirements of the RoHS directive, and the factory has implemented the EN ISO 9001: 2008 quality management system. Each product sold is automatically tested - the manufacturer has at its disposal professional test and measurement facilities, ensuring that their commercially available fans not only meet 100% their technical specifications, but also are cost competitive on our market.
Proof of the reputation and quality of these products can be seen in the fact that Maxair is the OEM supplier for, among others, Hyundai Elevator, to which it sells 80 thousand AC fans per annum. One of their major advantages is the perfect balance of the rotor. In addition, they are characterized by high performance while maintaining low noise levels. On special request they may be made from materials of reduced weight, corrosion resistant, and with an increased operating life at high or low temperatures.
Overview of products available
One can find many types of fans being sold, including all popular standard sizes, such as 80x80x25, 80x80x38, 92x92x25, 92x92x38, 120x120x25, 120x120x38 and round versions measuring 172x150x51 mm. The largest units are 254 mm in diameter with a thickness of 89 mm. It is worth noting that with relatively large capacities, Maxair fans boast a relatively quiet operation – a noise level ranging between 20 dBA for small units to 50 dBA for the largest fans.
These excellent results are the effect of high precision mechanical machining of the rotor blades and balancing of all the moving parts, thus avoiding vibration. Fan efficiency is linked to their dimensions and indirectly with the power of the motor, but for details it is necessary to consult the company’s catalogue. However, due to the specifics of AC voltage power and the use in such fans of a squirrel-cage induction motor with a consistent start-up phase, fan speed is more or less constant, being related to the power voltage frequency at a level of 1,500...3,000 rpm depending on the model.
Fairly large in size, Maxair fans are characterized by relatively quiet operation. Versions featuring ball bearings operate in a temperature range of –30...+75°C, and for versions using plain bearings the temperature range is –10...+70°C.
X-FAN’s DC fans
The X-FAN company is one of the largest Taiwanese manufacturers of cooling systems, producing more than 30 million fans and blowers annually and operating on the market since 1994. The company focuses on providing high-quality products - all the materials and manufacturing processes are closely monitored and comply with environmental safety standards and such quality standards as CE, UL, and TUV. The company supplies its products to such renowned manufacturers as Sony, Philips, Samsung Electronics, Panasonic and LG. The company offers fans powered by alternating current and direct current. The range of fans is very wide and includes versions with the rotor located in a frame and extended outside the structure (external rotation). It is also worth mentioning that the fans of the X-FAN company are available in options with an external signal that indicates the speed of rotation, i.e. a signal with a frequency proportional to the rotation, which allows precise control of rotation and control of their operation (removal of dirt)
There are also versions available with an alarm output, where the output signal indicates whether or not the rotor is spinning. Yet another option is speed control as a function of temperature. Models with this feature allow one to attach a thermistor to the fan, thus ensuring ease of operation. A final group of functions involves models in which the rotation speed is set by sending a PWM (pulse-width modulation) signal from a microcontroller.
Overview of products available
The main part of the company’s product range comprises DC axial fans with housings in the form of a rectangular frame. They are used in electronic devices, automation systems and power systems. Most of the parameters of these products, such as performance and noise generated are associated with their size. The smallest units start at 25x25 mm and a thickness of 10 mm, with subsequent models having dimensions 10 mm larger, and thus 20, 40..., up to 90 and 120 mm. The typical thickness of the fan is 10-15 mm for the smaller units and 20-25 mm for the larger units, but there are also non-standard thickness, such as 30x30x6 mm or for large versions also 28, 32 and 38 mm. The company also sells large fans for installation in industrial housings and cabinets allowing for the cooling of an entire system. These have dimensions of 182x171x82 mm or 172x150x51 mm. The operating voltage of DC fans is: 5, 12, 24, 36 and 48 V, although the extreme values are not available for all versions.
Source: "Elektronika Praktyczna" 2020 nr 5, p. 98-99.