Brushless DC (BLDC) fans are the most common type used to cool electronic equipment. Many cooling fans now have additional functions which provide greater control the fan speed and operation, thus improving the system performance. Having a fan run constantly even when maximum cooling is not required, does not result in an efficient system and can reduce the service life of a fan. If the average speed of the fan is reduced to 50% of its rated maximum speed, its service life can be approximately doubled, thus improving the reliability and availability of the whole system and reducing the maintenance costs.

Fan speed controller ICs are available for use in designing forced-air thermal management systems. Besides simple fan speed control, those ICs can include several important functions, such as detecting fan failure and closed-loop fan speed control for improved system performance. Cooling fan speed control options include:

Auto-restart

If the fan can't start due to obstacles, this may cause thermal lag problems or failure conditions. To solve this problem, most modern DC cooling fans feature auto-restart protection, which can detect when the fan motor is prevented from rotating and automatically cut off the driving current.

Tachometer Signal

Cooling fan motor and sensor for the tachometer share the same supply voltage. The tachometer signal can also detect fan failure or identify an impending failure of the fan. Detects rotational speed of cooling fan motor and provides a pulsed output. If motor stops, output stops pulsing and stays at logic high or low.

3-wire fans have a locked-rotor signal in place of the tachometer output. The locked-rotor signal indicates when the fan stops spinning but does not provide the tachometer’s detailed speed information of a tachometer.

Rotation Detector

Doubles as a lock sensor where output remains at logic low during normal operation, but is driven to logic high if fan motor stops.

PWM Control Signal

4-wire fans have all of the connections of 3-wire fans and add a PWM speed-control input and provide the ability to control the speed of the fan. Instead of modulating the power to the fan, the PWM input is used to control fan speed. That means that the power to the fan is continuously available, making the tachometer output continuously available. Duty cycle of this input determines speed of fan’s rotation, relationship between duty cycle, and whether fan’s speed is linear.

4-wire PWM cooling fans can be operated at frequencies above the audible frequency range, eliminating audible noise. The recommended PWM frequency for these fans is typically between 15kHz and 30kHz, but some can operate as high as 100kHz. The PWM speed-control input is usually compatible with 3.3V or 5.0V logic.

When used with a microcontroller one can create a sophisticated thermal management solution used to adapt to system conditions and provide more efficient operation.

1. When purchasing cabinet cooling fans, first confirm the size of the cabinet, select the appropriate fan model and appearance for installation, and then determine the parameters such as voltage, airflow, speed, current, noise and other parameters.

2. Cooling fan voltage, which can be divided into DC voltage 5v, 12v, 24v and 48V; AC voltage 110V, 220v, 380v. If the wrong voltage is connected, the cooling fan will be burned out, and the cabinet will also be damaged, causing adverse effects.

3. Confirm the service life of the cabinet cooling fan. The service life of sleeve bearing is about 30,000 hours, the service life of the hydraulic bearing is about 40,000 hours, and the service life of the ball bearing can reach about 80,000 hours.

4. The quality of the stator and copper wire will also affect the quality of the cooling fan of the cabinet. (Copper wire includes pure copper wire, aluminum clad copper, and even iron clad copper. The stator is also divided into pure steel and steel strip). The quality of copper wire and stator directly affects the service life of the cooling fan. Good copper wire and stator increase the speed and directly affect the service time of the cabinet.

5. The power line is also very important. Confirm the required length of the line. If the power line is peeled off or copper wire is exposed at the welding place, do not use it. It will cause personal injury and electric shock if the consequences are serious.

6. Generally, the frame and blades of DC cooling fans are made of PBT material. Usually, the operating temperature of the cooling fan is between -10 ~ +70°C, and the humidity is between 20% ~ 85%. Beyond this range, the AC cooling fans made of aluminum alloy can be selected.

The production of industrial equipment is inseparable from the accessories industrial cooling fan. The main function of the fan is to dissipate heat, cool and remove dust for various sizes of equipment. The general production environment of industrial equipment is relatively harsh. In order not to shorten the service life of the industrial cooling fan, some treatment will be done for the fan. The following are some of the more common anti-corrosion measures for industrial cooling fans.

Appearance treatment of industrial cooling fans: The surface protection treatment of cooling fans usually adopts galvanizing, chrome plating, chemical plating and other methods. These methods are valid in many environments, but for rotating parts, you must choose carefully. Because the substrate and the coating are two kinds of materials, their linear expansion coefficients are different, which will produce different deformations in the elastic deformation of the rotating parts, which will produce a large number of micro-cracks and accelerate the formation of corrosion. Therefore, the appropriate process must be selected according to the actual use environment.

Design of industrial cooling fan: The design of cooling fan is the performance of its core technology, and also affects the service life of cooling fan. In the structural design of cooling fans, the design defects most prone to accelerated corrosion are stress concentration tendencies and interstitial environments. Sometimes the corrosion rate in the metal immersion solution is small, but the formation of gaps can cause severe crevice corrosion due to changes in the chemical and electrochemical states of the internal solution, which requires careful design.

Materials of industrial cooling fans: Different cooling fans use different materials and have different anti-corrosion effects. After selecting the cooling fan model, the strength of the parts is determined from the base surface according to the corrosion resistance of different materials in different environments, the main application environment, working strength and other factors.

Guangdong Chungfo Electronic Technology Co., Ltd. focuses on the cooling needs of equipment in various industries. We are a cooling fan manufacturer specializing in R&D and supply of DC cooling fans, AC cooling fans and DC blower fans, etc. The product quality is excellent, the cooling fan gauge is complete, and the professional customization of cooling fans can be provided according to customer needs.

With the advent of the industrial era, the number of factories is increasing, the purchase of more and more mechanical equipment, but to extend the use of mechanical equipment, it is necessary to heat it, then with the application and environmental temperature changes, the need for different speed of the cooling fan to meet the heat dissipation needs of the equipment. The normal operation of the cooling fan is crucial to the stability and security of the device. So do you know how to deal with the common faults of cooling fans? The following lists several common faults of DC cooling fans and AC cooling fans and the corresponding solutions:

1.Abnormal sound:

(1) The fan suddenly makes noisy noise

Reason: This is usually because the lubricating oil of the fan is dry, or the fan is dusty.

Measures: As long as the heat pipe radiator and the fan are separated, the fan is cleaned up, and a little lubricating oil can solve the problem.

(2) Abnormal sound When rotating, you can occasionally hear some small collision sound

Cause: The chassis is covered with messy data cables and power cables. The cable ends touch the blades of the DC cooling fan, causing abnormal sound when the fan rotates.

Measures: You can use rubber bands, adhesive paper, etc. to tie the scattered data cable power cord in the chassis to avoid passing over the cooling fan.

2.The cooling fan automatically offsets the position

Reason: The buckle fixing the radiator fails, and the resonance phenomenon caused by operation leads to the displacement of the fan

Measure: Replace the new buckle

3. The rotation is not smooth

Reason: The speed of the cooling fan is slow when it is just started, and it can be restored to normal after a short period of time. Due to the low indoor temperature of the cooling fan, it is easy to lose the effect of the lubricating oil on the rotating bearing.

Measures: Add antifreeze lubricating oil to the cooling fan, and pay attention to the temperature of the surrounding environment when using.

4. Overload protection trigger

Cause: After long-term operation, the cooling fan may be triggered by overload protection. The reason for the protection trigger may be that the power output voltage is too high or the fan load is too large.

Measure: Reduce the load on the fan and ensure that the load is within the rated load range of the fan. If the output voltage of the power supply is too high, replace or repair the power supply.

5. The controller is faulty

Cause: Some advanced AC cooling fans have a circuit controller, if the controller fails, the controller line is damaged, the controller chip is faulty, the fan can not work properly.

Measures: Check whether the controller circuit and chip are damaged, and repair or replace the controller. If it is a line fault, you can rectify the fault by checking that the line is properly connected or testing the line using a multimeter. If the chip is faulty, professional equipment needs to be used to detect and repair the chip.

Guangdong Chungfo Electronic Technology Co., Ltd. is dedicated to the equipment cooling needs of various industries, is a professional cooling fan manufacturer. We can provide professional customization of cooling fans according to customer needs. If you have this need, please feel free to contact us.