Electric: basic knowledge of 16 transformers. (Ⅱ)

What is an auto transformer?

The vehicle has only one set of coils, and the secondary coil is pulled out of the primary coil. Its electricity transmission includes not only electromagnetic induction transmission, but also electrical transmission. The number of sheets of silicon steel and copper wires of this transformer is less than that of ordinary transformers, and it is often used to regulate the voltage.

How is the pressure regulator regulated?

The structure of the pressure regulator is the same as that of the auto transformer, except that the iron core is wound on the iron core of the ring as a ring coil. In the tap of the secondary coil, a sliding contact brush is used so that the ring glides over the surface of the coil, providing a smooth effect of voltage control.

What is the ratio of the current between the primary and secondary windings of the transformer?

When the transformer works with the load, the change in the current of the secondary coil will cause the corresponding change in the current of the primary coil. According to the principle of the magnetic potential balance, the current of the primary and secondary coils is inversely proportional to the number of coil turns. The current on the side with a large number of turns is smaller, and the current is on the side with a smaller number of turns larger. This can be expressed as follows: the current of the primary coil/current of the secondary coil = rounds of the secondary coil/inlets of the primary coil. 9. What is the rate of change in the transformer voltage?

The rate of change in the pressure regulator is one of the main indicators of the effectiveness of the transformer. When the transformer supplies the power to the load, the voltage at the end of the transformer load inevitably decreases. Compare the reduced voltage value with the value of the rated voltage and take the percentage as the speed of change in the voltage, which can be expressed by the formula; The rate of change in voltage = [(secondary rated voltage-tension on load terminals)/secondary rated voltage] × 100%. A typical power transformer has a voltage change in 4-6% when connecting to a nominal load.

How to make sure that the transformer has a nominal output voltage?

If the voltage is too high or too low, this will affect the normal operation and life of the transformer, so it is necessary to adjust the voltage. The voltage regulation method is to introduce a few taps into the primary coil and connect them to the opening of the drive. The hole of the crane changes the number of coil turns, rotating the contacts. Just turn the position of the device switching to obtain the required nominal voltage value. It should be noted that voltage regulation should usually be carried out after the load connected to the transformer.

What are usually used small transformers? What are the applications?

Small transformers belong to single -phase transformers with a capacity of less than 1 kVA, mainly used as power transformers for electrical equipment control, power transformers of electronic equipment and power transformers for safe lighting.