There are two windings inside the motor, one is the main winding, which is the running winding, and the other is the secondary winding, which is the starting winding.
The live and neutral wires of a single-phase motor can be connected reversely. As shown in the figure above, by changing the position of the live wire, that is, changing the wires connected to both ends of the capacitor, the forward and reverse functions of the motor can be realized.
We can see from the picture above that when we set the multimeter's resistance setting and place the two test leads at point A and point B respectively, the resistance between AB is actually the starting winding and the running winding. The result of stringing them together, so the resistance is the largest. The smaller one is the resistance of BC, that is, the resistance of the starting winding; the smallest one is the resistance of AC, that is, the resistance of the running winding, and satisfies AC+BC=AB. (The main winding resistance of most single-phase motors is smaller than the secondary winding)
As shown in the picture, adding a reversing switch is actually changing the wiring at both ends of the capacitor. At this point, we should roughly understand the use of single-phase motors.
Extended informationWorking principle of the motor
Schematic diagram
As can be seen from the picture above, this circuit can be divided into three parts. The leftmost 220v AC circuit , the swing circuit in the middle, and the fan circuit on the far right. The electric fan motor is a single-phase AC motor. It has two windings inside, one is called the running winding (also called the main winding), and the other is the starting winding (also called the auxiliary winding).
The starting circuit is composed of split phases, so that the main and auxiliary windings are spatially separated by 90° electrical angle. The speed regulating circuit is composed of a reactor speed regulating switch connected in series. By adjusting the size of the reactance, the voltage of the motor is changed to achieve speed regulation. After understanding this circuit diagram, it is enough to repair the electric fan.
The fan is one of the common parts we use in air conditioners. It is mainly used to filter and transport indoor air, reducing indoor temperature and purifying the air. When using air conditioners in the summer, we can use fans to cool down, dissipate heat and adjust the indoor temperature. However, we also know that fans are used very frequently. If used improperly, the fan may not spin or may have difficulty starting.
1. Fan blades
For air conditioning fans, the fan blades mainly play the role of wind. After the air conditioner is started, it will blow the indoor air outdoors and play the role of cooling and purifying the air. Therefore, the fan blades of the air conditioner must ensure sufficient strength. The fan blades of the air conditioner motor are designed to filter the indoor air and transport it to the outdoors, thereby achieving the effects of cooling and purifying the air. If an air conditioning fan is used for too long, the blades will become fragile and aged, and can easily break, affecting the fan's starting effect and service life. It is also possible that the fan does not rotate due to foreign matter on the air conditioner blades or improper use of the fan. At this point, simply reinstalling the fan will solve the problem.
2. Fan motor
When we usually use air conditioners, there are three components: the air conditioner main unit, the stator and the DC motor. If the fan motor is idling, it is most likely that the causeIt is difficult to start because the motor is faulty. Then we can solve this problem by checking the fan motor. Check the fan motor. If the fan motor fails, then we can replace the fan motor or extend the service life of the fan motor.
3. Terminal post
It is the intermediate component connecting the air conditioner and fan. When the fan fails to start, the fan terminals may be poorly wired. We can check whether the fan terminal is damaged or stuck. If the fan jams, you can replace the fan accessories or fan to solve the problem, and then continue to use the air conditioner; if the fan cannot start, you can check it out and solve the problem by replacing the terminals and adjusting the wiring.
4. Case
There is a problem with the fan case and the fan motor does not rotate. Solution: Open the case and check whether the screws are loose and difficult to rotate. If the screws are loose, they need to be replaced. What will happen if they are not replaced? You can disassemble the filter to see if there is dust stuck in the holes, or clean the areas that have not been disassembled cleanly. If the fan case is too dirty and the fan motor fails to rotate or is difficult to start, the fan motor should be replaced in time. If the fan does not spin or is difficult to start, you need to disassemble the fan case, disassemble the air filter a little, and clean the motor.