Micro transformers are important equipment in the power industry, including micro-current transformers and miniature voltage transformers, and are usually used for measurement and protection in a variety of power instruments.
Compared with ordinary transformers, micro-transformers have smaller size (nail cover size can be achieved) and high accuracy (ordinary transformers are 0.5, 0.5S, 0.2, 0.2S four precision grades, while the latter can reach level 0.1) and so on. In the miniature transformer, the miniature current transformer has no resistance on one side, while the ordinary current transformer is the transformer of the parallel resistor on the two side, and the output is the current. The miniature current converter in the miniature current transformer is a parallel resistor on the two side and the output is a voltage.
Micro current transformer is divided into multi-turn winding type (plugged in the circuit board) and wearing the heart type two ways of use. It should be noted that in the process of using micro-transformers, especially current transformers, it is necessary to identify whether there is damage to the current transformer, today we introduce a good way to identify whether there is damage to the power transformer, we can take advantage of the principle of voltammetry,
Because the core of the current transformer is in a state of gradual saturation, if under the short-circuit current, then the core of the current transformer will slowly tend to saturation. In practical applications, the current transformer in the miniature transformer can ensure that the relay is able to operate normally and stably under the short-circuit current. For example, when the excitation current is rising at an ultra-fast rate, the excitation current in the current will account for a lot more, which will cause the difference to gradually become negative and will continue to increase negative values.
Because the action current of the relay is many times higher than the rated current. In the process of identifying the current transformer in the micro-transformer, the error curve of 10% can be made by voltammetry before using the current transformer, and two coils can be checked at the same time when the voltammetry characteristic curve is measured, mainly to check that it has no short circuit between the turns.