Electronic fan resistance working principle, electronic fan resistance is broken symptoms.
Convert electric current into heat
The electrical resistance of the electronic fan works mainly by converting current into heat energy.
The resistor in the electronic fan, also known as the thermistor, has a core role in monitoring the temperature of the motor windings. When the temperature of the motor winding increases, the resistance value of the thermistor will decrease. This change is due to the negative temperature coefficient relationship between the resistance value of the thermistor and the temperature, that is, as the temperature increases, the resistance value will decrease. When the resistance value reaches a certain temperature, it will drop to a certain value, which will cause the pre-value circuit to power off operation, so that the electric fan stops working. This mechanism is actually a protective effect on the electric fan, preventing damage due to overheating.
In addition, the working principle of resistance also involves the conversion of current. When the current passes through the resistor, due to the thermoelectric effect of the resistor, the surface temperature of the resistor will rise, and the current value will also change. By adjusting the current, the parameters of the resistance can be adjusted, such as the resistance value and the current value, so as to achieve the stability of the circuit and prevent overcurrent phenomenon.
In the application of electronic fans, the resistance not only plays a protective role, but also participates in the speed regulation and temperature control process of the electric fan. For example, in the automotive electronic cooling fan, the operation of the fan is controlled by different control methods (such as the "thermistor switch + relay" control mode), and the speed of the fan is automatically adjusted according to the water temperature or speed. This control method not only improves the efficiency of the electric fan, but also ensures its safe operation.
The main symptoms of electrical fan resistance failure include:
The air output cannot be adjusted, that is, the air output of the fan cannot be adjusted as required.
There's no 1234 gear, there's only one outlet, or it doesn't work.
These symptoms indicate that the resistor of the electronic fan may have been damaged, causing it to not work properly. The resistor acts as a current limiting and overvoltage protection in the circuit, and when it is damaged, it may cause the air output of the fan to be unable to be adjusted, or it may not work at all. In addition, when the resistor is working normally, its resistance is infinite, when the input voltage exceeds a certain value, its resistance will suddenly become smaller, so that the circuit is short circuit, forcing the fuse to burn short, play a role in protecting the appliance.
How to measure the electric fan resistance correctly
First, the role of electric fan resistance and common faults
The resistance of electric fan is one of the key components to control the running speed of motor, which is realized by changing the power supply voltage. Common faults include resistance damage, poor contact or open circuit, etc., which will cause the motor to not work properly.
Second, the steps and methods of measuring resistance
1. Disconnect the power supply and remove the fan cover to expose the resistance.
2. Use a multimeter to touch the measuring rod to both ends of the resistance. The multimeter should be set to the resistance measuring gear. If the resistance is adjustable, set the multimeter to the rheostat gear so that the resistance can be read correctly.
3. Read the resistance value and compare it with the calibration value of the resistance meter. If the reading is close to the calibration value, the resistance is normal; Otherwise the resistance is damaged.
Third, precautions
1. When measuring resistance, the power supply should be excluded first to avoid accidents.
2. If a multimeter is used to measure the adjustable resistance, twist the resistor to the maximum value before testing to avoid damage to the resistor.
3. If the resistance contact is not good, use detergent to clean the contact parts and check whether the screws are fastened.
Iv. Conclusion
By using the above method of measuring resistance, we can quickly and accurately determine whether the electric fan resistance is damaged, so as to replace it in time and ensure the normal operation of the electric fan. At the same time, it is recommended to pay attention to safety when using electric fans and not to overuse them for a long time.
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