Transformer principle

inductance

Probe current voltage pin 420*4450 head diameter 5.0 over current current and voltage pin

Introduction: This paper describes the principles of transformers, current transformers and transformer into the transformer inductance, let Xiaobian to introduce the principles are the two transformers are interested in it ~ ~ ~ Come basin faithful Take a look~~~

1. Transformer principle - introduction

An instrument transformer, also known as an instrument transformer, is a general term for devices that convert voltage or current proportionally and current transformers and voltage transformers. Its function is mainly to convert high voltage or large current into standard low voltage or standard small current, so as to realize standardization and miniaturization of measuring instruments, protection equipment and automatic control equipment. At the same time, the transformer can also be used to separate the high voltage system to ensure the safety of people and equipment.

2. Transformer principle - classification

Transformers are divided into two major categories: voltage transformers and current transformers . Voltage transformers can be used for voltage and power measurements in high voltage and high voltage power systems. Current transformers can be used for the measurement of exchange currents, the measurement of exchanged electrical power, and the protection of electrical drag lines.

The main functions of the transformer are: accurately transmitting the voltage and current information of the primary system to the secondary side related equipment; converting the high voltage and large current of the primary system into the low voltage (standard value) and small current of the secondary side ( Standard values) standardize and miniaturize devices such as measuring instruments, relays, and relays, and reduce insulation requirements for secondary equipment; electrically isolate secondary and secondary systems from primary system high voltage equipment. In order to ensure the safety of the secondary equipment and the human body.

3. Transformer principle - voltage transformer

The principle of electromagnetic induction is applied to voltage transformers. Once the voltage U1 is generated on the primary winding, a magnetic flux is generated in the core. According to the law of electromagnetic induction, a secondary voltage U2 is generated in the secondary winding, wherein the ratio of U1 to U2 depends on the primary winding and the secondary winding. The turns ratio can be used to form a voltage transformer that converts voltages in different proportions as needed.

When the voltage transformer is in operation, the primary winding is connected to the line, and the secondary winding is connected to the meter or the relay. Therefore, when measuring the high voltage, although the primary voltage is high, after the transformation, the secondary voltage is low voltage, and the direct measurement can be Ensure the safety of operators and instruments.

4. Transformer principle - current transformer

The current transformer is made up of the characteristics that the original and secondary currents of the transformer are proportional. The working principle and equivalent circuit are also the same as the general transformer, except that the primary winding is connected in series in the circuit under test, and the number of turns is small; the secondary winding is connected to a low-impedance load such as an ammeter or a relay current coil, which is approximately short-circuited. The primary current and the secondary current depend on the load of the line under test, regardless of the secondary load of the current transformer. Since the secondary side is close to the short circuit, the primary and secondary voltages U1 are both small, and the exciting current I0 is also small.

When the current transformer is running, the secondary side is not allowed to open. Because once the circuit is opened, the primary current becomes the excitation current, which makes the magnetic flux and the secondary voltage greatly exceed the normal value and endangers the safety of people and equipment. Therefore, fuses are not allowed in the secondary circuit of the current transformer, and it is not allowed to remove the ammeter, relay and other equipment without bypassing during operation. The wiring method of the current transformer is determined according to the operation requirements of the load to which it is connected. The most common wiring methods are single phase, three phase star and incomplete star.

The introduction of the principle of transformers is over here. Here are some articles related to transformers. I hope everyone can read them~~~

1. Current transformer basics

2. Advantages and problems of electronic transformers

3. Principle of voltage transformer - How does the voltage transformer work??

Transformer