Animation: Operating principle of a 3-phase alternator

The top left-hand section of the animation shows a cross-section of a 3-phase alternator. The alternator has 3 windings, which are shown in 3 different colours.

The level of the currently induced voltage can be described by three formulae, which are shown in the top right-hand section:

These formulae describe the sinusoidal induction voltages as a function of time t for each of the 3 windings. The phase shift of 120 degrees can be explained by the arrangement of the induction coils, which are rotated by 120 degrees to each other. Û (U with circumflex) stands for the maximum voltage (amplitude). The symbol ω (omega) represents the angular frequency.

The maximum voltage Û can be calculated using the following formula:

  • Û is the maximum voltage (amplitude) of the induced alternating voltage.
  • k is a proportionality constant that depends on the specific properties of the generator.
  • B is the field strength of the excitation magnet.
  • A is the effective area of the conductor cross-sections through which the magnetic field passes.
  • n is the speed of the generator

The factors B and n can be influenced in the animation via two virtual controllers. The lower section shows the voltage curve and the pointer diagram (complex number plane).

Note on use

After starting the application, you can view the animation in full-screen mode. To do this, click on “View” and then on “Full screen”:

To exit full screen mode, press the Esc key.

Overview and download

TitleOperating principle of a 3-phase alternator
Target groupTeachers and lecturers
PlatformsMicrosoft® Windows®
Apple® Macintosh®
FeaturesFull screen mode
lossless zoom
Large screens and projection screens supported
DownloadContact us


C. Hein, S. Rikowski

Source information


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