In addition to the DC brushless motor, there is another type of shaded pole induction motor in the exhaust cooling fan.

As the name suggests, Induction motors is because electromagnets in the stator induce magnetism in the rotor. They induce magnetism in the rotor because, unlike the rotor in a brushless DC motor, the rotor in an induction motor contains no magnets.

A separate small winding is used in the stator, called the shielded coil. The electromagnets in the stator are formed by coils around steel laminations. The shading coil is wound around a small section of the laminations. When ac is supplied to the main winding, a portion of the resulting magnetic flux links to the shading coil. This induces a current in the shading coil which behaves like the secondary of a transformer. The induced current, in turn, produces its own (weak) magnetic flux which lags the magnetic flux in the main portion of the stator. Consequently, there is a time and space displacement between the two fluxes. This time and space displacement sets up the conditions for a rotating (or shifting) magnetic field. The rotating magnetic field is what starts and keeps the rotor turning.

Some shielded pole motors do not use shielded coils. Instead, they use a small gap in the lamination, which is enough to generate the hysteresis magnetic field needed to rotate the rotor.

The advantage of AC cooling fan shaded pole motors is that they are inexpensive because they have a pretty simple construction. But the problem is that they are inefficient, mainly because of the lossy linkage between the shaded coil and main winding. The efficiency of shaded pole motors generally is only between 15 and 30%. And the power factor is rather low as well.

A low power factor and efficiency is probably ok for applications where there is only one small cooling fan (shaded pole motors are generally 40 W or less). But consider an application like a data center, which includes racks and racks and racks and racks of severs, and each of those servers has its own fan. It is not advisable to have hundreds or even thousands of fans all operating at only 30% efficiency. Brushless motor technology and its efficiency of 90% are more suitable for these applications.

The AC cooling fan needs maintenance after it has been used for a period of time, so that it can be used for a long time and its service life can reach the standard. What are the maintenance skills for AC cooling fans?

1. Open the shell of the equipment, then turn on the AC fan, turn off the power supply of the equipment, use the air gun 2cm away from the fan, and blow the fan; Then use industrial alcohol to wipe the dirt on the fan blades, then tilt the machine body to adjust the gap position, and then use the air gun to blow out the dust in the equipment. From the front of the equipment to the back of the equipment, it needs to be cleaned, and then rotate repeatedly until it is clean.

2. The wind speed of the AC cooling fan is determined by many factors, two of which are the bearings of the AC cooling fan,

Ball bearing: the long-term oxidation of air ions in the air to the bearing and the accumulation of dirt and dust will increase the friction resistance of the bearing and gradually reduce the speed of the fan.

Oil bearing: the AC fan with oil bearing mainly rotates by the mutual friction between the stator and the coil, and the oil in the bearing gradually decreases with the use of the fan, non-stop work and time consumption, resulting in slower and slower wind speed when the fan is used for work.

3. The service life of the AC fan varies according to different service environments. Assuming that it works in a standard environment, the service life of the general AC ball fan is about 50000 hours, and the products of different cooling fan manufacturers will also be differentiated. The service life of general AC oil bearing fan is 25000 hours.

4. Due to the repeated rotation of its bearings, the service life will be shortened due to wear, and the service life of high-quality manufacturers will reach 30000-35000 hours; The equipment shall be cleaned at least once a month. The air inlet network shall be kept clean to prevent blocking the air flow. It can be cleaned with a soft brush or compressed air.

The cooling fan is a small part, but it is not a dispensable part, but a part with extraordinary functions. Now most electronic devices have been popularized in our life. Cooling fans are required for household appliances and entertainment electronic facilities. So how can we protect our "little heart" from harming innocent people, affecting the normal use of the equipment and prolonging its service life. Chungfo is a fans manufacturers specializing in the production and sales of DC cooling fans, AC cooling fans, axial fans, centrifugal fans and blower fans. Pay attention to the Chhungfo brand, and we will share more knowledge about cooling fans with you.