Characteristics and application of miniature current transformer

- Jul 17, 2020-

The application range of the miniature current transformer is getting wider and wider, and its specifications and models are getting richer and richer, with higher cost performance, users can choose according to their needs. And there are some precision miniature current transformers including ring-shaped silicon steel or permalloy cores, which can meet the requirements of different users.

In practical applications, this precision type miniature current transformer can be used in some more special work occasions. Normally, silicon steel cores are suitable for medium precision and low cost requirements, current measurement and current relays; and permalloy cores are suitable for high precision and small phase error requirements for current, power and energy monitoring equipment, The cost is relatively high.

In the production process, the shell material of this series of miniature current transformers is made of PBT resin material, and the flame retardant level reaches 94-V0. The internal insulation is encapsulated with epoxy resin and meets environmental protection requirements. In practical application, what is the self-calibration method of the test device? The technical requirements for this product are: the in-phase components are within ±0.01%, and the quadrature components are within ±0.5 minutes.

Therefore, the appropriate confirmation instrument should be selected first, and the environmental conditions of the test should be ensured. The load resistance is usually zero (ambient temperature is 10℃-35℃, relative humidity is not more than 80%, and there is no calibration work around the workplace Irrelevant electromagnetic field). Use the miniature current transformer of the test machine as the measured current transformer, connect it to the transformer testing device for testing, and record the ratio difference and angle difference of each point.

After that, the data measured by the instrument should be compared with the actual test data of the miniature current transformer used in the test machine provided by the manufacturer. The difference between the in-phase components within ±0.01% and the difference between the quadrature components within ±0.5 points are qualified. Keep in mind that the calibration cycle should not exceed one year, and can be calibrated at any time if necessary. It will be carried out by the metrological management personnel, and relevant records shall be required.