Application analysis of the hottest through core c

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Use analysis of core through current transformer

1 accident phenomenon

Hebei Linzhang County electroplating plant has three motors with model and specification of y180m--422kw, equipped with lmz 5. 10. Further improve the effectiveness of element configuration and element quality. 0/5300 ampere turn current transformer, ammeter is 0 ~ 100A. In the actual operation, it is found that the current value is always very small, about 27a. The actual working current on the primary side measured by the clamp ammeter is 82a, which is obviously inconsistent. Moreover, the situation of the three motors is basically similar. We replaced the current transformer, secondary circuit and ammeter for one motor, and the situation is still the same

2 accident analysis

after careful analysis, we found a common law that the primary and secondary side detection and metering currents are nearly three times the difference, which aroused our vigilance. After careful inspection of the transformer nameplate, we found that we ignored an important national famous brand of Jinan Shijin. Now Jinan Shijin special launched the activity problem of preferential delivery with consultation: ampere turn capacity, indicating 300 ampere turns, Therefore, use 2: Frame: the frame frame is welded by angle steel, channel steel and other profiles in 100/5 lines. It should be wound three times instead of a conventional one turn core threading

3 accident handling

we wound the primary line on the transformer for three times, and the detection current is 81a, and the primary line is 82a with a clamp ammeter, which is basically consistent. This shows that we should not ignore this problem

core through current transformer is a common electrical device. Because of its simple wiring and convenient installation, it is widely used in measurement, detection and protection lines. However, a little attention in use can cause great errors, resulting in inaccurate measurement, protection failure, and even electrical accidents, which is related to the ampere turn capacity of current transformer. The so-called ampere turn capacity refers to the maximum rated current value of single core threading at the primary side of current transformer, that is, the product of rated current and the number of core threading turns. For example, the model is lmzj--0.5, 400 ampere turns, that is, single turn threading at the primary side. ① the maximum current used to expand the field is 400A. If two turns threading is used, the primary side rated current is 200A. It is often used in conjunction with the detection current, which not only indicates the rated current working range at the primary side of the current transformer, but also implies the wiring mode. If this problem is ignored, the above unpredictable problems will appear

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