Connect DIS tester and select test modes — «Measurement system» And «Generator check». If the AB charge indicator is constantly on, then it is necessary:
- remove the voltage regulator and check the protrusion of the carbon brushes, replace them if necessary. Minimum length of carbon brushes «A» - 5.0 mm (A. fig. 353), if less, replace the alternator voltage regulator.
If the battery charge indicator goes out when the engine is running, then it is necessary to check the value of the regulated voltage, if it is not reached, then it is necessary to replace the regulator.
To check the generator with BSD and the voltage regulator, use a comparative analysis of the oscillograms, for which you connect a DIS tester and set the measurement modes:
- function selection;
- car as a whole;
- engine and transmission;
- voltage and current regulation;
- electricity generation;
Process the results of test blocks and waveforms.
The oscillogram of a working generator is shown in fig. 3.54.
Oscillograms of a faulty generator:
- one phase break (pic. 3.55 a);
- interturn short circuit (pic. 3.55, b);
- break in the negative diode (pic. 3.55, in);
- Short circuit in positive diode (pic. 3.55, g);
- break in positive diode circuit (pic. 3.55, d);
- break in the circuit of the diode and / or excitation winding (pic. 3.55, e).
In all these cases, it is necessary to repair or replace the generator.