Set Oscilloscope Display Alternator

The following image represents the voltage curve of an intact alternator. The height of the individual waves depends on the current load of the alternator. The length of the waves depends on the engine speed. The higher the engine speed the shorter the waves.

At idle speed with consumer units switched on, an error-free alternator should provide approximately this graphic.

Fig 1: Display - Examples Of Error-Free Alternator

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Examples of faulty alternators are shown below.

The current as a function of engine speed also applies here.

Fig 2: Display - Examples Of Faulty Alternators With Defective Diode Screen

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Alternator with defective diode

Fig 3: Display - Examples Of Faulty Alternators With Broken Coil Screen

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Alternator with broken coil