How to Choose the Right Electronics Cooling Fan
Selecting the right fan is important for your electronic designs!By Robert Cong
Fans spin and cool... simple, right? Actually, electronic components are never that simple. When it comes to purchasing the correct fan, you have to look at all the specifications such as size, speed and control in order to make the right choice for your application.
Fans can be AC Tube Axial for an AC current source, Blowers, or brushless DC Brushless Fans for DC current. There are a number of brands including Adda fans and Sunon fans each with their own specialty designs. Jameco also carries new products such as Peltier coolers, as well as fan accessories including heatsinks, fan guards, and fan cables.
Fan Input: It Won't Work If You Can't Power ItMake sure you know what kind of input will be provided before deciding on anything else. The most common voltage inputs are 12VDC, 24VDC, 48VDC, and 115-220VAC powered. Be sure your system can provide the required amount of current for the fan to operate.
Fan Size: Bigger Doesn't Always Mean BetterThe size of the fan will be determined by how much space you have to work with. The larger the fan does not always translate to higher speeds or better cooling. It simply means that a larger area will receive cooling. Conventional standards list the sizes in millimeters, and the most common are 40x40x10, 80x80x25, and 120x120x25.
Bearings: The Foundation Of A FanThe bearing on a fan tells you how the fan is built and also provides you with an idea of how long it may last. Ball bearing fans are the most common as they are simple and effective. They are also more durable at higher temperatures and fairly quiet at high speeds. They have a long lifespan, many lasting over 60,000 hours.
Sleeve bearing fans are also very common. They use lubricated sleeve surfaces which can be self-lubricating and require little maintenance. Although they are generally less expensive, they are also known to be less reliable long-term and do not perform as well as ball bearing fans in higher temperatures.
Hypro bearings are used exclusively from Adda Fans. They are recommended for fans with a minimum thickness of 10mm and for applications under 70°C. Hypro bearings are made of copper ferroalloy which have an above average lifespan and are water-resistant and good for low-noise applications. They also use lubricating oil within the system, which reduces friction but may cause additional wear once it dries out.
Benefits and Example:
Hypro bearings system also help eliminate parts that constantly need to be replaced after they wear out like O-rings and washers. Adda fans are mostly used to cool down computing parts such as the CPU or the power supply to prevent overheating. The lubricating oil is vital for the system to prevent the friction between the moving parts and decrease the sound. There are gaps that are prone to let the lubricating oil seep out of the system when evaporated due to high temperatures during long, continuous operation. Adda has updated the Hypro bearings traditional structure to an advanced one that fixes this issue. Here is an image of the updated version of the Hypro Plus:
Vapo bearings are exclusively from Sunon Fans. They are designed to virtually eliminate any wobbling, so they stay incredibly stable in all applications. They also stay dust-proof leading to much improved life expectancy.
Vapo bearings include MagLev (Magnetic Levitation) technology that assist in one of the industry's most effective designs that prevent wobbling, which increases the life of the fan as well. This magnetic feature as well as the lack of oil in the system, set it apart from the Hypro bearing model. The elimination of wobbling helps reduce wear on the fan, and provides exceptionally quiet performance that will provide longer life to these fans.
The MagLev motor fan has a rotation that is fully exerted by a patented 360° MagLev orbit that prevents it from slanting or swaying. It is suitable for any position or angle, with the bearing and shaft having no direct contact during operation, resulting in no friction or noise and a long lifespan for the fan. Some notable applications of Sunon fans would be for projectors that operate in high temperatures and demand low noise, audio applications that not only provide only low noise, but no resonance as well, and for portable applications such as laptops or game devices, they provide the ultimate solution for noise and thermal problems. Take a look at the diagram to see the many parts to this excellent design.
Speed And Airflow: A Major Factor In Staying CoolThe rotational speed of a fan is usually given in revolutions per minute (RPM). Combine the RPM speed with the static pressure of the given environment and you get the airflow of the fan, usually given in cubic feet per minute (CFM). This spec will tell you which fans push around the most air and provide the most cooling.
Connections: An Extra Lead Could Save EnergyMost fans have a simple 2-lead positive/negative connection, but some may include extra leads for various purposes. A third lead can be used in certain fans for locked rotor protection in case something gets caught in the propellers. Some fans also have a temperature sensor so that the fan only turns on once the system reaches a predetermined temperature, saving energy in the process. A tachometer lead may also be available for users that want to know exactly how many RPMs are being provided.
Fan Guards: You'll Want The Extra ProtectionFor those who want extra protection from debris and the harsh environment, there are fan guards and washable filters. Keep unwanted material from traveling in and out of your fans and prolong its life in the process.
ConclusionThere are many considerations to take note of such as agency approvals and noise levels, but those are fairly straightforward. If your projects require certain approvals, please make sure they are marked so.
Click here for explanations on Certifications and Approvals
Jameco is a preferred supplier representing the following manufacturers:
AVC America Inc.
Evercool Thermal Corp., Ltd
Fulltech Electric Co.