This project is a temperature controller for a PC FAN. It regulates the speed of the FAN attached to it according to measured temperature. Temperature is sensed using a simple NTC thermistor.
In most PCs the fan runs constantly, which may not be necessary. A simple circuit can regulate the fan speed according to temperature. This not only saves energy, it also reduces fan noise. Only three components are needed to allow the fan speed to be controlled according to the actual temperature: one adjustable voltage regulator (LM317T) and two resistors that form a voltage divider. One of the resistors is a NTC thermistor (temperature-sensitive resistor), while the other is a normal resistor.
Temperature Controlled PC FAN - [Link]
Silence at last – or what to do, if a silent operation of a fan matters to us?
Despite features of fans being still more improved, it´s still the fact, that they are usually the biggest noise source in devices. If a given device is intended say for a production hall, where an ambient noise is much higher, we probably don´t have to worry about it. But at devices intended for common rooms, offices, households etc., it´s naturally important to maintain the noise of a device as low as possible. If dimensions of a device allow it, it´s usually better and more silent solution to use a fan with a bigger diameter and a lower rotation speed. However, what to do when the size and a design of a fun suit us, but a power, rotation speed and consequently a noise are still uselessly high?
A partial solution is to decrease a supply voltage. Computer enthusiasts know very well, that a noise of a given fan depends (besides its aerodynamic construction) on its rotation speed. Solid producers like Sunon, specify range of operating voltages and a rotation speed at a given voltage (for example 12V). Also in a datasheet can be usually found even a start voltage, at which a given fan will reliably start to rotate. By a change of a supply voltage, we can change a fan speed, but it´s not possible to go below certain speed (at a given fan type). It´s common, that for example a 12V fan still works at 4V (when decreasing from 12 to 4V) but it´s already not able to start at such a low voltage.
Probably the best solution is to use a slower fan (with a lower rotation speed). Today almost every series of fans is available in 2-3 power levels, what reflects in a noise but also in different power consumption. This can be illustrated on 2 types of the same construction – MEC0251V1-A99 (MEC0251V1-0000-A99) and MEC0251V3-A99 (MEC0251V3-0000-A99). As for a mechanical construction, they are the same. The only difference is only in a rotation speed – 3100 vs. 2200 turns per minute. This is then reflected in a noise 44,5 vs. 34 dB and in a power consumption 5,4 vs. 1,9 Watt. The noise difference 10,5 dB is really big ( 6 dB difference is subjectively perceived as a double volume) and in many cases it´s surely not negligible even a power consumption difference of approx. -65%. Should you still be satisfied with a lower air flow, it´s naturally possible even at these slower types further decrease rotation speed by decreasing a supply voltage. Naturally, there are even more silent fans on the market, but types from company Sunon offer a very good compromise among noise, power and a price.
Choose a fan with a low noise and low power consumption - [Link]
Over 60 years of experiences of German company EBM-PAPST in the fans development reflects in an uncompromising quality of products.
It may sound like a phrase, but to rely on a quality is almost always worth – mainly because of overall savings. Long lifetime and energy efficiency will at the end of the day reflect into lower operation expenses. Quality materials sophisticated construction, precise bearings and results from long-term tests say in favor of EBM-Papst fans. EBM-PAPST has in its testing laboratories 1500 operating fans and there can be even found fans continuously operating from 80´s (!). EBM-Papst is quite stringent regarding a declared lifetime and in comparison to other producers it declares „less optimistic” values, as illustrated on an enclosed picture. It means, that if we compare 2 fans from various producers with similar features, it´s very probable that the type from EBM-Papst will have a higher real lifetime. In the EBM-Papst portfolio can be found practically all types of fans and blowers, from smallest to massive industrial ones, axial, radial (centrifugal), diagonal a tangential. The most of fans is also available in a version resistant to dust and water with IP54. EBM-Papst is a pioneer in the development of energetically efficient fans with a significantly lower power consumption and a quieter operation, for example the ACmaxx and GreenTech_EC series.
EBM-Papst portfolio is very wide, that´s why we keep in stock only a few most wanted types and any other type we´re able to provide you upon request. To the standard stock items we newly added also the type 7056ES – AC fan with of a 150mm diameter. 7056ES is a well proven powerful type with a ball bearing and an all-metal construction. Precise ball bearings SINTEC feature a constant low noise during all the lifetime and a low sensitivity to impacts. 27W motor contains an external capacitor and a thermal fuse against overload. High air flow – 330m3/hr, i.e. over 90 litres per second make this type a universal choice for ventilation of various spaces or cooling of electronics and similar.
Fans able to operate continuously for 30 years - [Link]
The MAX31740 is a sophisticated, yet easy-to-use fan-speed controller. It monitors the temperature of an external NTC thermistor and generates a PWM signal that can be used to control the speed of a 2-, 3-, or 4-wire fan. The fan control characteristics are set using external resistors, thereby eliminating the need for an external microcontroller. Controllable characteristics include the starting temperature for fan control, PWM frequency, fan speed at low temperatures, and slope of the temperature-duty-cycle transfer function.
MAX31740 – Ultra-Simple Fan-Speed Controller - [Link]
Zak Kemble build an AVR based PWM fan controller. He writes:
So this is a bit of a continuation on my 555 timer based PWM controllers, but now using microcontrollers and MOSFETs instead of 555 ICs and transistors. I made 2 versions, one with switches for speeding up and down and the other with a potentiometer like the previous controllers. I used ATtiny25 controllers running at 31.25KHz (8MHz internal RC / 256 prescaler) with a 3.3V supply, the MOSFETs I used are STP36NF06L with 0.045Rds and 2.5Vgs max, perfect for 3.3V, the MOSFETs only generate ~180mW of heat at 2A ((0.045Rds * (2A * 2)) = 0.18W) so no heatsink needed, you can barely feel them getting warm.
AVR microcontroller based PWM fan controller - [Link]
Sometimes even a small fan significantly improves thermal conditions in a device. For these cases will serve you the new types of small fans.
Sunon, as an innovative producer of fans and the creator of progressive technologies (VAPO, MAGLEV,…) consistently extends its portfolio, or replaces older types by new ones. This is also the case of new types in our offer – EB40201S2-999, EB60201S1-999 with a sleeve bearing, MB40101V2-A99, MB40201V1-G99, MB50101V2-A99 and MB60101V2-A99 with a VAPO bearing, which gradually replace the KD and KDE series.
New types feature even higher reliability thanks to a construction with a lower count of mechanical parts. They also feature a higher air flow (better flow/pressure characteristics) while keeping the same or a lower noise. If you consider adding an active cooling to your device, whether from the necessity or for increasing of reliability of your device in extreme cases, you can choose from more Sunon, types which we keep in stock. Upon request, we´re able to provide you with any other type from the Sunon portfolio.
New 40, 50 and 60mm Sunon fans will blow away excess heat - [Link]
Any electronic system generates waste heat during normal operation. This heat must be removed – otherwise, it might damage the system components and cause malfunctions. Whether you are designing a system or diagnosing a system’s cooling requirements, you need to know which parameters to look at and how to estimate the airflow that will maintain a safe temperature within the system.
In a typical cabinet-mounted system, there are usually one or two power supplies, electronic circuits and displays, all of which can be assumed to generate heat within the cabinet. From the system’s power requirements, a fair idea of the power input may be estimated. If the system is cooled by simple convection, the thermal capacity of air can be taken to be 0.569W-minute/°C/ft³.
That means, every cubic foot of moving air can remove 0.569 W of dissipated heat every minute when its temperature changes by 1°C. To express it reciprocally, to dissipate 1W of heat, and maintain a 1°C change in temperature, an air stream of 1.757cfm (1.757 cubic feet per minute) will be required. Therefore, once you have estimated the heat dissipation within the system, estimating a cooling fan’s rating in cfm will depend on the internal temperature rise you allow. However, until you have completed your measurements and fitted the right size of fan, there will always be the risk of failure of system components. Therefore, for experimentation, what you need is a representative model.
This application note describes the operation of 12 volt DC cooling fans typically used to supply cooling air to electronic equipment: These fans are typically based on two-phase Brushless DC (BLDC) motors drawing between 1 and 50 watts of power. Single-phase brushless DC motors are also used in fans, but this is outside the scope of this application note.
Further discussion describes the addition of an Atmel ATtiny13 microcontroller and the benefits this offers, such as variable speed by external thermistor input. An additional input is a PWM pulse width-varying signal, which also controls fan speed.
App note: PC fan control using an ATtiny13 - [Link]
Geoff designed this USB PC case fan controller. It is used to control the speed of your fans depending on the temperatures in your case. Software that was developed for this project allows you to customize the temperature profiles for your computer.
The project is based on the PIC18F2550 that is connected to the computer via the USB and uses the standard Molex 4pin connector to access computer’s power supply. It has 4 analog inputs for temp sensors, and can control up to 8 fans.
One thing to note is that all the fan outputs work with 3 pin fans, while two are universal and work even with 4 pin PWM versions. The 3 pin fans are driven with a buck convertor. The UDN2981 provides the high side switch and diode that are driven from PIC’s PWM signals. A 100uH inductor and a 479uF capacitor complete the buck topology, thus providing variable analog output for the 3 pin fans.
Intelligent Fan Controller - [Link]
I’ve got a new tool on my workbench – portable fume extractor. It’s 92mm fan that works from 4 AA batteries and has a variable speed. Mobility is a really good thing, especially when you’ve got a tons of equipment and cables on a bench you can drown in.
Portable Fume Extractor / Fan - [Link]