- the battery must be fully charged;
- all consumers, except for the battery and the ignition system, must be turned off;
- engine speed should be 2500-3000 min-1. Measure the voltage at the battery terminals with a voltmeter. If the voltage does not exceed 14.5 V, the regulator is working. If it is greater, then connect the regulator housing to the car body with a separate conductor and measure the voltage again.
If in the second case the voltage is again increased, therefore, the regulator is faulty and must be adjusted or replaced. If the voltage is normal, then the reasons for overcharging the battery are in poor connection of the regulator housing with «weight».
A faulty voltage regulator can be identified by checking its internal parts.
The reasons for the failure of the regulator may be the following:
1. Break in thermal compensating resistor 2 (rice. 7-11) or the regulator winding, while the voltage is not regulated and rises excessively. This malfunction can be detected by checking the electrical resistance between the plug with an ohmmeter «15» and «weight» (basis).
2. Break in the winding of the inductor or in the additional resistor 4; while the regulation is unstable (sudden voltage fluctuations).
The fault is detected when checking the electrical resistance between the plugs «15» and «67» with open contacts of both the 1st and 2nd stage.
3. Contamination, burning or oxidation of the 1st and 2nd stage contacts when the regulated voltage is unstable.
A malfunction can be caused by the penetration of foreign substances into the regulator: oil, gasoline, water, which contaminate the contacts, or a short circuit in the plug wire circuit «67» or in the excitation winding of the generator. Foreign matter entering the regulator is due to improper installation or deterioration of the gasket between the cover and the base of the regulator, or if the gasket is made of the wrong material and does not provide a reliable seal or releases volatile substances.
If the contacts are damaged, it is recommended to check the condition of the circuits (short circuits and correct wiring), as well as the health of the generator.