Switching group

Three-phase transformers, or three-phase transformers, are labeled as follows according to the globally common and more understandable approach for the user.

The 1. capital letter describes the primary input winding and the 2nd lower case letter the secondary output winding.

If no other order information with a more precise assignment of the position of the upper and lower clamping is formulated, the above-mentioned type of labeling is selected! Three-phase transformers are preferably manufactured in Dyn5 if no specifications are available.

Load capacity of the neutral conductor (neutral point)
In the star-wye connection (Yy), the star point may only be loaded with the full rated current if the neutral conductor of the supplying network is connected to the primary-side transformer star point. If this is not the case, the neutral point can only be loaded with approx. 10% of the phase conductor current.

The same rule applies to three-phase autotransformers that are designed as star autotransformers (YNa0). If a fully loadable star point is required, but this is not available on the mains side, the double zigzag connection (ZZan0) must be selected.