Iron core structure of current transformer

    At present, our country is still mainly producing electromagnetic current transformer. According to the primary insulation division of primary winding, transformer can be divided into general dry type, resin pouring type, oil paper insulation type and SF6 gas insulation type, and so on, and the structure is very different.

    The current transformer core materials are commonly used cold-rolled silicon steel sheet of permalloy and Fe based nanocrystalline alloy etc, silicon steel sheet is suitable for core level protection, also suitable for general measurement level core, widely used, relatively low prices, permalloy and ultracrystalline alloy material with high initial permeability, low the characteristics of magnetic saturation rate, but the price is high, only for the requirements of high precision, the coefficient of the instrument for measuring the level of core strict.

The common iron core forms of current transformers include laminated iron core, coiled core (also called ring iron core), open core, etc..

    1, laminated iron core. A cold rolled silicon steel sheet along the rolling direction (i.e. field lines) tied by punching into strip strip, then fold up into the mouth. Laminated iron core is mainly used in 35kV and below small current transformer.

    2, roll core, a strip of cold rolled silicon steel sheet is made into a circular shape, oval, rectangular and variety. The performance of the coil core is very ideal. It is widely used in 35kV and above current transformers, and other large current transformers are also used frequently.

    3, open core. Also known as the iron core with air gap, it will roll core vacuum impregnation or epoxy resin after curing, and then cut into two or more flap in the cutting machine, the incision in the non-magnetic gasket pad with air gap width after using stainless steel banding into a complete open core core, mainly in the current the transient characteristics of the transformer requirements.