The working principle of cooling fan is realized according to the energy transformation, namely: electrical energy → electromagnetic energy → mechanical energy → kinetic energy. Its circuit principle is generally divided into a variety of forms, the use of different circuits, the performance of the fan will be different.
Parameters such as the following table:
Specifications 120x120x38 Model No. YA21238HBL
Type Cooling Fan(AC) Voltage 110V/220V/380V
Rotation Speed 2400~3000 RPM Current 0.3 A/ 0.6 A/
Category
Axial Fans
The blades of an axial fan push air to flow in the same direction as the shaft. The impeller of an axial fan is somewhat similar to a propeller in that it operates with the vast majority of the airflow flowing parallel to the shaft, in other words along the axis. Axial fans have the lowest power consumption when the inlet airflow is free air at 0 static pressure, and the power consumption increases as the counterpressure of the airflow rises during operation. Axial fans are usually mounted on the cabinet of electrical equipment, sometimes also integrated in the motor, due to the compact structure of the axial fan, can save a lot of space, and easy to install, so it has been widely used.
Features:Higher flow rate, medium air pressure
Centrifugal fans
When a centrifugal fan operates, the blades push the air to flow in a direction perpendicular to the shaft (i.e., radial), with the intake air along the axis and the discharge air perpendicular to the axis. In most cases, the cooling effect can be achieved by using an axial fan, however, sometimes a centrifugal fan is necessary if the airflow needs to be rotated 90 degrees to discharge or if a larger air pressure is required. Fans are also technically centrifugal fans.
Characteristics: limited flow rate, high air pressure
Mixed-flow fan
Mixed-flow fan, also known as the diagonal flow fan, at first glance, mixed-flow fan and axial fan is not different, in fact, mixed-flow fan inlet is along the axis, however, the outlet is along the diagonal of the axial and plumb line direction. This type of fan results in higher air pressure because of the conical shape of the blades and the outer casing, and the centrifugal fan makes less noise than the axial fan for the same size and other comparable performance.
Characteristics:High flow rate and relatively high air pressure
Through-flow fans
Through-flow fans produce airflow over a large area and are often used to cool large surfaces of equipment. This type of fan has both inlet and outlet air perpendicular to the axis (as shown at right). The cross-flow fan works using a relatively long drum-shaped fan impeller, the caliber of this drum-shaped fan blades are relatively large, because the caliber is large, in order to ensure the overall amount of air circulation on the basis of the use of a relatively low rotational speed, thus, reducing the noise due to high-speed operation.
Characteristics: low flow rate, low air pressure
Bearing structure
Introduction
Common bearings for cooling fans are: ball bearings, oil bearings, magnetic levitation bearings.
Ball Bearing
Ball Bearing changes the friction method of the bearing, using rolling friction, two iron rings in the middle of some steel balls or steel columns, and supplemented with some grease lubrication. This way more effectively reduce the friction phenomenon between the bearing surface, effectively improve the service life of the fan bearing, but also so that the heat of the radiator is reduced, the service life is extended. The disadvantage is that the process is more complex, resulting in higher costs and higher operating noise.
Oil-containing bearings
Oil-containing bearings (Sleeve Bearing) are sleeve bearings that use sliding friction, using lubricating oil as a lubricant and dampening agent. It is arguably the most common type of bearing technology on the market today, and many products, including well-known brands, continue to be in use due to their low cost and simple manufacture. The advantages are quiet, low noise and cheap for initial use.
Magnetic Levitation Bearing
Magnetic Levitation Bearing (Magnetic Bearing) motors use Magnetic Levitation (Magnetic System, MS) design, which is the use of magnetic force to suspend the rotor in the air, so that there is no mechanical contact between the rotor and stator. The principle is that the magnetic induction line and the magnetic levitation line becomes perpendicular, the core and the magnetic levitation line is parallel, so the weight of the rotor is fixed in the operation of the track, the use of almost no load of the core of the shaft to the direction of the anti-magnetic levitation line of the top of the support, the formation of the entire rotor suspended in the air, in the fixed operation of the track. Compared with traditional ball bearings and oil bearings, magnetic bearings do not have mechanical contact, and the rotor can run to a very high rotational speed, which has the advantages of small mechanical wear, low energy consumption, low noise, long service life, no need for lubrication, and no oil contamination, etc., and it is especially suitable for high speeds, vacuums, ultra-clean environments, and other special environments. Magnetic levitation is in fact only an auxiliary function, is not an independent bearing form, the specific application also has to cooperate with other forms of bearings, such as magnetic levitation + ball bearings, magnetic levitation + oil bearings, magnetic levitation + vaporization bearings and so on.
Technical indicators
Air volume
Air volume refers to the total volume of air discharged or incorporated into the cooling fan per minute, if calculated by cubic feet, the air volume unit is CFM; if calculated by cubic meters, it is the CMM. cooling fan is often used in the unit of CFM (about 0.028 m3 / min).
Airflow is the most important indicator of a cooling fan's ability to dissipate heat. Obviously, the higher the airflow, the higher the cooling capacity of the cooling fan. This is because the heat capacity ratio of air is certain, a larger air volume, that is, more air per unit time can take away more heat. Of course, the cooling effect of the same air volume is related to the way the wind flows.
Air pressure
Air pressure and air volume are two relative concepts. Generally speaking, in order to design a fan with a large airflow, some air pressure has to be sacrificed for the manufacturer's cost-saving considerations. If the fan can drive a large amount of air flow, but the wind pressure is small, the wind can not blow to the bottom of the radiator (this is why some fan speed is very high, the air volume is very large, but is not good heat dissipation), on the contrary, the wind pressure is large often means that the air volume is small, there is not enough cold air with the heat sink for heat exchange, will also result in a bad heat dissipation effect.
Fan speed
Fan speed is the number of rotations of the fan blades per minute, in rpm. fan speed is determined by the number of turns of the coils in the motor, the operating voltage, the number of fan blades, inclination, height, diameter and bearing system **** with the decision. RPM and fan quality are not necessarily related. The speed of the fan can be measured either internally with a speed signal or externally.
As applications and ambient temperatures change, different fan speeds are sometimes required to meet the demand. Some manufacturers have deliberately designed cooling fans with adjustable fan speeds, both manual and automatic. Manual is mainly to allow users to use a low speed in winter to get low noise, and high speed in summer to get a good cooling effect. Automatic class temperature control radiator generally with a temperature control sensor, according to the current operating temperature to automatically control the fan speed, high temperature is to increase the speed, the temperature is low is to reduce the speed, in order to achieve a dynamic balance, so as to let the wind noise and cooling effect to maintain an optimal combination of point.
Fan noise
In addition to the cooling effect, fan noise is also a common concern. Fan noise is the size of the noise generated when the fan is working, and is affected by a variety of factors, measured in decibels (dB). Measurement of fan noise needs to be carried out in the noise less than 17dB muffler room, one meter away from the fan, and along the direction of the fan axis aligned with the fan air intake, the use of A-weighted way to measure. The spectral characteristics of the fan noise are also important, so it is also necessary to use a spectrometer to record the frequency distribution of the noise of the fan, the general requirement is that the fan noise should be as small as possible, and there can be no abnormal sound.
Fan noise is related to friction and air flow. The higher the fan speed, the greater the air volume, the greater the noise caused by the fan, in addition to the fan's own vibration is not to be ignored. Of course, high-quality fan's own vibration will be very small, but the first two are difficult to overcome. To solve this problem, we can try to use a larger size fan. Should be in the case of the same air volume, the larger fan in the lower speed of the working noise is less than the smaller fan in the high speed of the working noise. Another factor that we tend to ignore is the bearing of the fan. As the fan rotates at high speeds, there is friction and collision between the shaft and the bearing, so it is also a major source of fan noise.
Applications
Widely used in computers, communication products, optoelectronic products, consumer electronics, automotive electronics, exchangers, medical equipment, heaters, chillers, inverters, teller machines, car coolers, welding machines, induction cookers, audio equipment, environmental protection equipment, refrigeration equipment, and other traditional or modern instruments and equipment.