Current-type signals, the external characteristics of the ideal situation, is equivalent to a very large voltage source in series with a very large internal resistance. In this way, when the load impedance is much smaller than its internal resistance, the current is always equal to its “short circuit current”. Its main advantages are: as long…
Before talking about accuracy and linearity, let us talk about the concepts of several errors: 1. Absolute error: the difference between the measured value and the ideal value; 2. Relative error: the ratio of the absolute error of the measured point to the ideal value of the measured point; 3. Reference error: the ratio of…
In order to obtain the best suppression effect on common mode interference, the common mode inductor core must have high magnetic permeability and excellent frequency characteristics. In the past, most of the ferrite core materials used for common mode inductors have excellent frequency characteristics and low cost advantages. However, ferrite also has some insurmountable weaknesses,…
If the current transformer is cut off at a large current, or the secondary winding is accidentally opened during operation, and after a test with a DC current, residual magnetism may occur in the core of the transformer, which will reduce the magnetic permeability of the core. Affects the performance of the transformer; therefore, before…
1.When the current increases, the magnetic density of the core also increases proportionally. At this time, the magnetic permeability μ and the loss angle ψ also increase, the error of the transformer decreases, the ratio difference decreases, and the phase difference decreases much. 2.The error is inversely proportional to the square of the number of…
The primary winding structure of the current transformer has two forms of single-turn type and multi-turn type. Single-turn type: The winding is only one turn at a time, and the structure is relatively simple. The primary current is more than 300 to 600A. It is divided into two types: bar type and bus bar type.…