Advantages and applications of toroidal transformers
As the name implies, a transformer with a toroidal core is called a toroidal transformer. Compared with transformers using other types of iron cores, toroidal transformers have the following advantages:
1. Simple structure, convenient iron core processing and low cost
2. The processing stress of the iron core is small, and the magnetic properties of the iron core material can be fully utilized. The magnetic properties of the ring iron core are better than those of other types of iron cores.
3. Small flux leakage.
4. Wide range of applications, from low frequency to high frequency, from power transformers to pulse transformers and other transformers can be applied.
The main application areas of toroidal transformers are:
1 Power transformer: Due to the improvement of the performance of the toroidal woolen machine, the use of toroidal transformers for power frequency power transformers has gradually increased. The toroidal iron core is easy to manufacture, large in size, simple in structure, low in cost, and small in magnetic flux leakage, so it is widely used in audio-visual equipment such as audio. In addition, among intermediate frequency (power frequency 400Hz, 1000Hz, etc.) power transformers, toroidal transformers are widely used in aviation and aerospace because of their small size and light weight.
2. Pulse transformer and broadband transformer: Due to the good performance of the toroidal transformer core and the small leakage inductance of the transformer, it is widely used in low-power pulse transformers and audio and high-frequency broadband transformers.
3. High-resistance transformers or inductors: High-resistance transformers require their iron cores to have high magnetic permeability, and toroidal core transformers are the first. Since the toroidal core is a magnetic circuit with no obvious air gap, the magnetic resistance is the smallest, and the toroidal core has the smallest influence on the magnetic properties of the material. Therefore, compared with other shapes of iron core transformers, under the same material conditions , The magnetic permeability of the toroidal core is the highest, and the cathodic reactance of the transformer is also the highest.
4. Use precision alloys, amorphous alloys, and ultra-microcrystalline alloy iron core transformers: Because the above alloy materials have high stress in the process of processing into iron cores, while the processing stress of toroidal iron cores is the smallest, only Only the toroidal core can best reflect the excellent magnetic properties of the above alloy materials. Therefore, most of the transformers using this type of material are toroidal transformers.
 
 
For the calculation of various data of the toroidal power transformer, first of all we know the following main parameters of the transformer:
Primary voltage U1=220V , frequency F=50Hz
Secondary voltage U2=50V, current I2=1.8A
The temperature rise is less than 75K;
Use Z11-0.35mm monolithic wound I-grade iron core.