FprEN 50209:2026

Test of insulation of bars and coils of high-voltage machines FprEN 50209:2026

Publication date:   Jan 23, 2026

Scope

This document applies to rotating electrical machines with rated voltages (UN) from 5 kV to 27 kV inclusive and with rated output from 5 MVA upwards for generators and from 5 MW upwards for motors.
This document is also applicable to machines with rated outputs between 1 MVA (1 MW) and 5 MVA (5 MW) and with rated voltages of 5 kV and above, provided its use has been agreed beforehand.
Requirements for machines with a rated voltage above 27 kV are the subject of individual agreement.
In the case of machines whose windings are cured in the stator, tests on the separate winding elements are not possible; for these machines the requirements in Clause 6 apply.
Converter fed machines are excluded from the scope of this standard. The described tests can be used for this type of machines however the criteria are mutually agreed upon between user and manufacturer.