The structure of single-phase EI transformer core and its grounding method

- Nov 01, 2018-

The single-phase EI transformer core is the main magnetic circuit part of the transformer. It is usually made up of hot-rolled or cold-rolled silicon steel sheets with high silicon content and coated with insulating varnish. The iron core and the coil wound thereon form a complete electromagnetic induction system, and the magnitude of the transmission power of the transformer depends on the material and cross-sectional area of the core.


In order to ensure the safety of the single-phase EI transformer core, it is necessary to reliably ground it, and it is possible to reduce the grounding lead wire of a single iron yoke clamp separately. Because if a single-phase EI transformer core encounters a multi-point ground fault caused by the upper clamp, the ground current flows only inside the core clamp, and no current flows through the core ground lead, which may cause the worker to mistake the core. There is no fault; after setting, no matter where the iron core hits the clip, it will form a loop through two grounded outer leads, so that the ground current can be detected correctly on the outside.


Or, place the single-phase EI transformer core grounding piece in the middle of the cross section of the iron yoke. In this way, no matter where the iron yoke pulls the insulating bolt and where the fault grounding point is, the maximum induced voltage of the loop is only 1/4 of the 匝 voltage. At this time, the maximum ground current is only a few amps or so. The grounding lug is much smaller when placed in other locations.


If it is necessary to place the single-phase EI transformer core grounding piece in other positions due to problems such as inconvenient installation on site, the insulating bolt of the yoke pull strap and the grounding lug should be placed diagonally to prevent large currents from being generated.