Detection of a direct current component in an inductive device

A method for detecting a direct current component in an inductive device, transformer or inductor, the method comprising using a computer for:

• recording an oscillation signal of a sound emitted by the device or of a mechanical oscillation of the device;
• determining a frequency spectrum of the oscillation signal;
• determining a value of at least one odd harmonic in the frequency spectrum;
• comparing the value of the at least one odd harmonic with a value of at least one even harmonic in the frequency spectrum;
• determining a direct current component when the value of the at least one odd harmonic differs by a predefined extent from the value of the at least one even harmonic;
• and
• specifying a probability of a presence of a direct current component for determining the direct current component, and increasing the probability as an amount by which the value of the at least one odd harmonic differs from the value of the at least one even harmonic becomes greater.