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Principle of current transformer
- Jun 01, 2018 -

In power lines, the current varies widely from a few amperes to tens of thousands of amperes. In order to facilitate the measurement of instruments and instruments, conversion is required

In addition, the voltage on the power supply line is relatively high. For example, direct measurement is very dangerous to instruments, instruments and people.

Therefore, the designed current transformer plays the role of variable current and electric isolation.

The pointer current display instrument is mostly ampere-level, so the secondary current of the current transformer is mostly ampere-level (such as 5A), while the computer

The signal of sampling is usually milliampere level (0-5v, 4-20ma, etc.). Therefore, the micro current transformer (the secondary current is milliampere level) is adopted as the current

The secondary transformation of current is carried out between the ct and the computer sampling signal.

The current transformer consists of a primary coil, a secondary coil, an iron core, an insulation support and an outlet terminal. The core of the current transformer is made of silicon steel sheet

As a result, the primary coil is connected with the main circuit in series, and through the measured current I1, it generates alternating magnetic flux in the iron core, so that the secondary coil can sense the phase

The secondary current I2 should be (its rated current is 5A). If the excitation loss is ignored, I1n1=I2n2, where n1 and n2 are one and two times respectively

The number of turns in the coil. The variable current ratio of current transformer K=I1/I2=n2/n1. The primary coil of the current transformer is connected to the main circuit, so one

The secondary coil must be ground - to - ground insulation material suitable for the primary circuit voltage to ensure the safety of the secondary circuit and person. The secondary circuit consists of a current

The current coil of the secondary coil, instrument and relay of the transformer is formed in series. Current transformers can be divided into two types, current mutual inductance for measurement

Current transformer for device and protection.