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Microwave oven transformer working principle and common troubleshooting

Update Time: 2023-08-03 10:09:08

What is the working principle of a microwave oven transformer? Let's first understand the structure of a microwave oven transformer. The microwave oven transformer has three windings, one of which is a primary winding, and AC 220V mains voltage is applied to this winding; a plurality of silicon steel sheets of a certain thickness are inserted between the primary and secondary windings, so that a high magnetic resistance is formed in the transformer. Gap magnetic shunt. So what is the working principle of microwave oven transformers, and how to repair common faults of microwave oven transformers? Let's take a look at the specific situation.
What is the working principle of the microwave oven transformer
When the magnetron of the microwave oven transformer works, an oscillating current flows in the secondary high-voltage winding of the transformer, causing the iron core to generate magnetic saturation. Assuming that the anode voltage of the magnetron rises and the anode current increases due to mains fluctuations, the current of the secondary winding of the transformer also increases, which deepens the magnetic saturation and increases the leakage magnetic flux, which makes the transformer secondary high voltage. Falling, that is, the anode voltage of the magnetron is decreased, and the anode current is decreased, otherwise the reverse is performed, thereby playing the role of automatically adjusting the anode voltage and current and stabilizing the microwave output power.
It can be seen that the microwave oven transformer mainly maintains the working current of the magnetron by the leakage magnetic flux, so it is also called the magnetic leakage transformer. This transformer can maintain the stability of the magnetron anode current under a wide range of city power fluctuations, so it has been widely used in microwave ovens. Except for special products, almost all microwave ovens use this type of transformer.
How to repair common failures of microwave oven transformers
Common faults of microwave oven transformers are: first, the microwave oven is not heated or the work is unstable due to poor contact of the lead plug; There are odors and other phenomena; Third, there is an open circuit or a partial inter-turn short circuit in the winding, and leakage or short circuit occurs between the winding and the iron core. Among them, the short circuit between the turns and leakage will also cause the microwave oven to increase the operating current and burn the fuse.
Microwave oven transformers have open windings or turn-to-turn short circuits. To repair them manually, the iron core must be disassembled and re-wound. However, the core of this high-voltage transformer is different from the core of ordinary transformers. In order to improve its reliability, the manufacturer has opened a total of 4 horizontal grooves on both sides of the core and welded all the silicon steel sheets together with welding rods. Due to the high hardness of the weld, 4 welds need to be removed with a hacksaw, file, or even a grinding wheel, etc., in order to disassemble the iron core silicon steel sheet, and at the same time, the burr caused by the silicon steel sheet must be polished and smoothed. . Because the iron core of the microwave oven transformer is very thick, there are many layers of silicon steel sheet, and it only takes a long time to remove the core and the way out of the silicon steel sheet. In addition, during the rewinding of the winding and the reassembly of the iron core, it is necessary to consider the heat resistance level and electrical strength of the high-voltage transformer, and ensure technical and material guarantees. Therefore, you need to repair it yourself. Requires high maintenance skills, and also requires a certain foundation in special tools and electrical materials.
About the working principle of the microwave oven transformer and how to repair the common faults of the microwave oven transformer, we has shared so much for everyone. In fact, for the answer to how to repair the common faults of microwave oven transformers, the simple way we can implement is to update the microwave oven transformer, but we wants to remind that the same type of microwave oven transformer is preferred. If you use other models for replacement, then Careful consideration must be given to the issue of power matching and voltage output.
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Tag: transformer