Micro current transformer site in general, the use of oil-free drying, but more manufacturers also believe that the product should be filled with oil to take the way of electric heating, in this case, that is, it is convenient for us to observe the temperature rise of the product itself.
This is particularly important for 220kv and more of its miniature current transformers. Since the insulation of these miniature current transformer products is thicker, if it is in an oil-free state, the conduction effect is poor, even if from the outside appears to be relatively low temperature, and internal insulation may be due to overheating and aging or even 忐 coke.
In view of this, it is best to heat up the product in an oily state, wait until the temperature rises and stabilizes before releasing the oil inside the product for oil-free drying. In the oil-free vacuum state, the current passing through the primary winding on the miniature current transformer cannot be higher than 70% of the rated current.
And for the micro current transformer short-circuit vacuum drying operation of the 1th, that is to note must be to remove the metal expander, loaded with vacuum, oil injection and its measurement of the joint or valve of the temporary cover plate. Micro current transformer short circuit method Vacuum drying operation of the second step, that is, to pay attention to the need to be a winding series wiring, the next words, that is, should be to pay attention to the need to use equal section copper wire to make it reliable short connection; After opening the two junction box, it is important to note that the outer wiring must be removed,
The two-arm bridge is used to measure its two winding DC resistance and record the corresponding temperature. The next step of vacuum drying operation of micro current transformer short circuit method, it is necessary to measure the ground insulation resistance of first winding with insulation resistance meter, and pay attention to recording the corresponding temperature. When the micro-current transformer short-circuit method vacuum drying operation, in the short-circuit state of a winding, we should pay attention to measure the characteristics of voltammetry itself.