Insulator MV

The windings are normally cylindrical. On request they can also be made with a rectangular shape, which is normally used for LV/LV windings in special application designs. MV windings are produced with the most advanced technology: • wire-type • strip-type Partial discharge tests We have performed partial-discharge measurements on several of our coils in accordance with the IEC 726 standards, detecting values ​​constantly below the level of 10 pico-coulomb (pC). We guarantee this level of partial discharge for the user, provided the assembly of the transformers respects the necessary dimensional and procedural parameters, and in particular the distance between HV and LV coils and distances to ground. Impulse test We have submitted numerous transformers assembled with our coils to impulse tests in accordance with the IEC 76.1.5 standards and a positive outcome has been obtained. Also for this type of test the observations concerning partial discharge tests remain valid and, that is, that the transformers must be assembled in accordance with the dimensional parameters. Thermal-shock test according to IEC 726 The test consists in lowering the temperature of the coil to -25° C over a period of 8 hours, and maintaining this temperature for a further 12 hours. It must then be powered with a current at twice the rated value, rising to an excess-temperature of 110° C without causing cracks.