Working principle and selection method of transformer
Writer： Hengfeng you electric Time：2021-09-26 views：times
This article describes the working principle of the transformer. Transformer is a device that transforms AC voltage, current and impedance. When a transformer transmits power, there is always loss. This loss mainly includes copper loss and iron loss. The core loss of the transformer is the main factor in the selection.
One, the working principle of the transformer
Transformer is a device that converts AC voltage, current and impedance. When the primary coil has an AC transformer principle process, an AC magnetic flux is generated in the iron core (or magnetic core), causing the secondary coil to generate an induced voltage (or current). ).
The transformer consists of an iron core (or magnetic core) and a coil. The coil has two or more windings. The winding connected to the power supply is called the primary winding, and the remaining windings are called the secondary winding.
In the generator, no matter? ? Whether the coil moves through the magnetic field or the magnetic field moves through the fixed coil, an electric potential is induced in the coil. In both cases, the value of the magnetic flux remains the same, but the magnetic flux intersecting the coil is different. Change, this is the principle of mutual inductance.
Transformer is a device that uses electromagnetic mutual inductance to transform voltage, current and impedance. Under the rated power, the ratio of the output power of the transformer to the input power is called the efficiency of the transformer, namely: η=(P2÷P1)x100%
In the formula, η is the transformer efficiency; P1 is the input power, and P2 is the output power.
2, transformer copper loss and iron loss
When the output power P2 of the transformer is equal to the input power P1, the efficiency η is equal to 100%, and the transformer will not produce any loss. But in fact, there is no such transformer. The transformer always produces loss when transmitting electric energy, and this loss mainly includes copper loss and iron loss.
Copper loss refers to the loss caused by the resistance of the transformer coil. When current flows through the coil resistance to generate heat, part of the electrical energy is converted into heat and lost. Since the coil is generally wound with insulated copper wire, it is called copper loss.
The iron loss of the transformer includes two aspects:
1. Hysteresis loss. When alternating current passes through the transformer, the direction and size of the magnetic lines of force passing through the silicon steel sheet of the transformer also change, causing the molecules inside the silicon steel sheet to rub against each other to release heat energy, thereby losing heat energy. Part of electrical energy. This is the hysteresis loss.
2. Eddy current loss. When the transformer is working, there are magnetic lines of force passing through the iron core, and an induced current will be generated in the plane perpendicular to the magnetic lines of force. Because this current forms a closed loop and forms an eddy current, it is called an eddy current. .The existence of eddy current causes the iron core to generate heat and consume energy. This loss is called eddy current loss.
The efficiency of the transformer is closely related to the power level of the transformer. Generally, the larger the power, the smaller the loss and output power, and the higher the efficiency. Conversely, the lower the power, the lower the efficiency.
The above is the main component structure of oil-immersed transformers organized by Hengfengyou Electric. If you still don’t understand, you can always contact our oil-immersed transformer manufacturer or call +86 15853252696 for further consultation, we will provide you with the best solution.