If you have even a little experience in assembling computer system units, then you might have noticed that sometimes processor cooling fan connectors, case fans have a different number of legs: 4 or 3. They are also called 4 pin and 3 pin, respectively. In relatively old system units on motherboards, only the processor fan has 4 wires, while the rest of the connectors are 3-pin. On modern motherboards based on the sixth or seventh generation of intel processors, as a rule, only 4 pin connectors are soldered, and 3 pins are already living out their short life and we will not see them in the next generations of coolers and fans.
What is the difference between three and four wired fans, besides the difference in the number of wires? Read the answer to this question later in this article.
Main Differences of 4 Pin vs 3 Pin Fans
Three pin fan connector- these are three indicators (by the number of wires): power (5 or 12 volts), ground and signal. The signal wire transmits the speed of rotation of the fan impeller at the normal nominal voltage of 4 or 12 volts. In this mode, the fan speed is usually controlled by increasing or decreasing the voltage on the power cable.
Four pin fan connector slightly different from the 3-pin connector as it has an extra (fourth) wire used to send control signals to the fan which has the chip. The chip controls the rotation speed of the fan impeller.
Three wire and four wire connectors
CPU fans mounted on a copper or aluminum heatsink (collectively, a cooler) use either a three-wire or a four-wire connector. Three-wire connectors are designed for small fans with low power consumption. The 4-wire headers are for CPU fans with higher power consumption.
When connecting a three-wire fan to a four-pin connector on motherboard the fan will always rotate, because the motherboard will not have the ability to control the 3 pin fan and adjust the speed of the cooler.
When connecting a four-wire fan to a three-pin connector on the motherboard, the fan will work without the ability to adjust the speed from the motherboard.
If suddenly the fan does not work, then you need to swap 3 and 4 wires in places so that the wire with speed control remains unused.
The size or diameter of the fan is measured in millimeters, for example, 120, 140, 92, 90, 80, 40, 50, 60, 200mm.
The thickness is usually 15 to 40mm.
PC fan mount
In most cases, PC case fans are mounted on screws made of some kind of metal.
Some models come with rubber, silicone or other mounts to reduce vibration and noise levels.
Fans are attached to the cooler's heatsink, most often with clamping frames or screws.
Types and types of bearings in PC fans
The type of bearing in a fan affects its performance and durability.
The bearings used in PC fans can be divided into two types: sliding bearings and rolling bearings, according to the principle of operation.
Near the name, there are numbers indicating the approximate possible time between failures of the bearing, under ideal conditions.
Plain bearings
Slip, simple(sleeve bearing) up to 35 t. h.
One of the most structurally simple plain bearings. Consists of bushing and shaft. Faster than others, it becomes unusable due to the high friction of parts.
The service life directly depends on vibration loads and temperature conditions. The emitted noise is low, but due to rapid wear, it can reach values that are unpleasant for hearing.
hydrodynamic(FDB bearing) up to 80 t h
An improved version of a simple one. The space between the bushing and the shaft is filled with grease, minimizing friction, which greatly increases the service life and reduces the noise level.
oil pressure(SSO) up to 160 t h
It differs from the previous one with a magnet centering the shaft, due to which wear is reduced, the amount of lubrication is increased, as a result of which it is more durable and quiet.
Self-lubricating(LDP) up to 160 t h
A special, more viscous, liquid or solid lubricant, strong film or coating is used. Improved the quality of processing of internal components…
with magnetic centering, levitation from -- - 160 to --
Practically, a non-contact mechanism based on the principle of magnetic levitation.
Very quiet (Up to 80% quieter than others...), more reliable, better tolerated in harsh environments.
Rolling bearings
Friction bearing(ball bearing) up to 60 - 90 t h
Rolling bearings, theoretically a bit noisier, but also more wear resistant.
They consist of rings, rolling elements (balls or rollers), a separator that holds the rolling elements in the desired position. The space between the bodies is filled with lubricant.
Ceramic(ceramic bearing) up to 160 t h
Manufactured using ceramic materials, withstands higher temperatures and has a lower noise level.
Types of fan connectors for PC
Warning!
If the fan has several different connectors for connection, then use only one of your choice, otherwise it is possible to damage the devices.
3pin and 4pin - pwn
General
Both are designed to connect to the motherboard.
For both connectors, the third pin is a tachometer that determines the number of revolutions and a signal.
Both types are mutually compatible, that is, it is possible to connect a 3pin to a 4pin connector and vice versa, observing the key. *
Differences 3pin from 4pin
The difference between 3pin and 4pin connector is as follows:
3pin the number of revolutions is fixed, as a rule, this is the maximum value, which is usually not initially controlled in automatic mode.
u 4pin adjustment is made automatically, due to the received PWM signal from 4 pins.
2pin
It is found inside power supplies, on video cards and ... It has only + 12v and ground (-), speed control is possible and is carried out by changing the voltage, with no information about the number of revolutions for the user.
Molex
Four pin connector used to connect to the power supply. As a rule, only two wires from 4, + and - from 12v are involved in it. Implies fan operation at maximum speed.
*
If you connect a 3pin connector to a 4pin connector or vice versa, then PWM control will not be carried out. If the motherboard is able to independently regulate the speed through the 3rd contact, by changing the voltage, then the adjustment will occur independently, if not, then it is possible to set a fixed number of revolutions in the BIOS, or leave it as it is, then the fan will work at maximum speed all the time .
Influence of parameters on fan operation
RPM- the number of revolutions per minute.
CFM- the maximum possible air flow per minute in cubic feet.
Noise level is measured in sons - sone or decibels - dBA. Quiet are considered with values up to 2000 rpm (RPM).
Example
Imagine two fans.
The example demonstrates (dependencies) that with a larger fan diameter and a lower number of revolutions, it is possible to obtain greater efficiency.
Backlight
Some models are equipped with lighting for decorative purposes. It can be either single-color, multi-color, or with a choice of color and effect. The presence of backlight affects both the cost and energy consumption.
If you have already built computers yourself, you may have noticed that in some PC models the coolers have four legs, while in others there are three. What is the reason for this design feature and does it have any practical use, or is it just another invention of designers? If this feature is technical, then what is the difference between coolers with three and four legs? Let's try to answer this question.
First, let's start with the fact that it is more correct to call fans with a different number of legs 3-pin and 4-pin. The described characteristic is technical and indicates the principle of operation of the cooler. Four-pin coolers are commonly found in modern motherboards. Also, four-pin coolers are most often used to cool the processor, while conventional ones can have three connectors. Guessing why this is necessary is not so difficult.
Fans with four legs are more advanced because they support the control of the impeller rotation speed. (using pulse-width modulation method) , which is very important for proper CPU cooling. This control is provided precisely thanks to an additional fourth wire that transmits a signal from the control chip to the fan. Does this mean that three-pin fans do not have such control? No, they also have their own signal wire, only the speed of rotation of the impeller depends on the change in the voltage of the power cable, although it should be noted that in some cases the speed control is purely symbolic.
If you take the picture as a whole, you should pay attention to the number of connectors on the motherboard itself, because they are also three-pin. Depending on whether the 3-pin and 4-pin module is connected to the 4-pin connector or vice versa, the fan will work differently.
3-pin to 4-pin connector. Speed control is carried out by changing the output voltage, but it may also be that the fan will spin constantly, since the motherboard will not be able to control it.
4-pin to 4-pin connector. Full control of the rotation speed is provided based on the indicators taken into account by the control chip.
4-pin to 3-pin connector. A four-pin cooler connected to a three-pin header may not work. Then you need to swap 3
and 4
wires, leaving the cable responsible for speed control unused. But in any case, the rotation speed control will not be carried out.
So which fan is better to buy? The future is clear 4-pin propellers, so if there are four connectors on the motherboard, it’s better to take them, of course. Another thing is the price, the latter can cost an order of magnitude more, so it all depends on the thickness of your wallet and the desire to have a more advanced cooling system.
Each house has accumulated a lot of computer fans: coolers from the processor, video card and PC power supplies. They can be put to replace burnt ones, or you can connect them directly to the power supply. There can be a lot of applications for this: as a blower in hot weather, airing workplace from soldering smoke, electronic toys and so on.
Fans usually come in standard sizes, of which 80mm and 120mm coolers are by far the most popular. Their connection is also standardized, so all you need to know is the pinout of the 2, 3 and 4 pin connectors.
On modern motherboards based on the sixth or seventh generation of Intel processors, as a rule, only 4 pin connectors are soldered, and 3 pin connectors are already a thing of the past, so we will only see them in older generations of coolers and fans. As for the place of their installation - on the PSU, video adapter or processor, it does not matter, since the connection is standard and the main thing here is the pinout of the connector.
4 pin cooler wire pinout
Here, the rotation speed can not only be read, but also changed. This is done with a pulse from the motherboard. It is able to return information to the tachogenerator in real time (3-pin is not capable of this, since the sensor and the controller are on the same power line).
Pinout of the cooler connector 3 pin
The most common type of fan is 3 pin. In addition to the minus and 12 volt wire, a third, “tacho” wire appears here. It sits directly on the sensor leg.
- Black wire - ground (Ground / -12V);
- Red wire - plus (+ 12V);
- Yellow wire - revolutions (RPM).
Pinout of the cooler wires 2 pin
The simplest cooler with two wires. The most common colors are black and red. Black - working "minus" of the board, red - 12 V power supply.
Here, the coils create a magnetic field that causes the rotor to spin inside the magnetic field created by the magnet, and the Hall sensor evaluates the rotation (position) of the rotor.
How to connect 3-pin cooler to 4-pin
To connect a 3-pin cooler to a 4-pin connector on the motherboard, for the possibility of software speed control, the following scheme is used:
When directly connecting a 3-wire fan to a 4-pin connector on the motherboard, the fan will always rotate, because the motherboard will not be able to control the 3-pin fan and adjust the speed of the cooler.
Connecting the cooler to a PSU or battery
To connect to the power supply, use standard connectors, but if you need to change the number of revolutions (speed) - you just need to reduce the voltage supplied to the cooler, and this is done very simply - by rearranging the wires on the socket:
So you can connect any fan and the lower the voltage, the lower the speed, respectively, its quieter operation. If the computer does not get very hot, but it is very noisy, you can use this method.
To power it from batteries or accumulators, simply apply a plus to the red and a minus to the black wire of the cooler. It starts to rotate already from 3 volts, the maximum speed will be somewhere around 15. You can’t increase the voltage anymore - the motor windings will burn out from overheating. The current drawn will be approximately 50-100 milliamps.
PC cooler device and repair
In order to disassemble the fan, you need to remove the glued nameplate from the side of the wires, opening access to the rubber plug, which we remove.
We pick up a plastic or metal half-ring with any object with a sharp end (clerical knife, a watch screwdriver with a flat slot, etc.) and remove it from the shaft. The view opens to a motor that runs on direct current according to the brushless principle. On the plastic basis of the rotor with the impeller, an all-metal magnet is fixed in a circle around the shaft, on the stator - a magnetic circuit on a copper coil.
Then clean the hole for the axle and drop some machine oil there, put it back together, put a plug (so that the dust does not clog) and use the already much quieter fan further.
All such fans have a brushless rotation mechanism: this is reliability, efficiency, noiselessness and the ability to adjust the speed.
In modern coolers, the connectors are much smaller, where the first contact is numbered and is a “minus”, the second is a “plus”, the third transmits data on the current impeller rotation speed, and the fourth one controls the rotation speed.