Let’s talk about the trouble first: when the hot air is turned on, the power will be cut off soon, but when the cold air is turned on, there is no problem. What’s the reason?

Take an electric hair dryer as an example, first introduce the internal circuit diagram of the electric hair dryer, as well as the internal structure of the electric hair dryer, and then analyze the cause of the failure, let’s take a look.

  

Figure 1, internal circuit diagram of hair dryer

  

Figure 2, internal structure of hair dryer

The above is the internal circuit diagram and structure of the hair dryer.

When the power is turned on, the motor is powered on and the wind blade rotates. The air is drawn in from the air inlet and blown out from the front nozzle of the air duct.

At this time, if the control switch is in the hot air position, the electric heating wire is electrified to generate heat and blow hot air; if it is in the cold air position, the electric heating wire is not heated and blow cold air.

  

Fig. 3 temperature controller inside the hair dryer

The temperature controller is also called the temperature control switch. The hair dryer is equipped with a temperature control switch near the heating wire. When the hair dryer works in the hot air range, the temperature control switch can automatically turn on the power supply. If the temperature of the heating wire is too high (such as the air outlet is blocked), the temperature control switch will automatically turn off the power supply to protect the heating wire.

When the hair dryer works in the hot air gear for a while, the power will be cut off. Check whether the internal circuit is normal, and check whether the air outlet of the air duct of the hair dryer is smooth.

In addition, when using the hair dryer, don’t make the air outlet too close to the object to be blown, otherwise the heating wire will overheat, and the temperature control switch will automatically cut off the power supply.

  

Figure 4, 1N5408 rectifier diode

1N5408 rectifying diode, its rectifying current is 3a, withstand voltage value is 1000V, the role of the diode is to adjust the temperature:

When the hair dryer is in the hot air position, the AC220V voltage is added to both ends of the heating wire; when the hair dryer is in the cold air position, the AC voltage is converted into pulsating DC power supply to the heating wire after being rectified by the tube, so as to adjust the temperature.

The protection of the temperature control tube is cut off. After a while, the temperature drops down and it can be turned on again. When the air duct is blocked, high temperature will be generated. General motor used for a long time, wind smaller, will lead to temperature rise.

In addition, the temperature controller will accelerate aging in the long-term high temperature environment. You can consider replacing the temperature control tube or a higher temperature control tube.

The one in the circle is rectifier diode, which is used for motor power supply. The motor is DC motor, and some advanced blowers use AC motor.

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