Method for determining a temperature in a winding of subconductors of an electric machine

A method for determining a temperature at a predetermined location in a winding of subconductors of an electric machine, each of said subconductors being sheathed with electrical subconductor insulation, said method comprising:

• predetermining the location between one of the subconductors and the associated subconductor insulation, wherein the location is a precalculated hot spot of the winding;
• arranging an optical fiber with a sensor material piece in the winding, wherein the sensor material piece is fitted to the predetermined location and the optical properties of the sensor material piece are temperature-dependent and not influenced by expansion;
• exposing the sensor material piece to light via the optical fiber, such that, after an interaction with the sensor material piece light is emitted by the sensor material piece;
• detecting the spectrum of the light;
• and
• determining the temperature at the predetermined location with the spectrum.