- the battery must be fully charged;
- all consumers, except the battery and ignition system, must be disconnected;
- the engine crankshaft speed should be 2500-3000 rpm.
Measure the voltage at the battery terminals. If the voltage does not exceed 14.5 V, the regulator is in good working order. If the voltage is higher, connect the regulator body to the car body with a separate conductor and measure the voltage again.
If in the second case the voltage is again increased, then the regulator is faulty and needs to be adjusted or replaced. If the voltage is normal, then the reason for the battery overcharging is a poor connection of the regulator body to the ground.
A regulator malfunction can be determined by checking its internal parts. The following may be the causes of a regulator malfunction:
- break in the temperature-compensating resistor R1 (see fig. 153) or the regulator winding. In this case, the voltage is not regulated and increases excessively. This malfunction can be detected by measuring the electrical resistance between the "15" plug and the base;
- break in the winding of the choke Dr or in the additional resistor. In this case, the regulation is unstable (sharp voltage fluctuations). The fault is detected by checking the electrical resistance between plugs "15" and "67" with open contacts of both the 1st and 2nd stages;
- contamination, burning or oxidation of the contacts of the 1st and 2nd stages, when the regulated voltage is unstable. The 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 wire circuit of the plug "67" or in the excitation winding of the generator. Penetration of foreign substances into the regulator occurs due to improper installation or damage to the sealing gasket between the cover and the base of the regulator, as well as if the gasket is made of an inappropriate material and does not provide reliable sealing or releases volatile substances. If the contacts are damaged, it is recommended to check the condition of the circuits (short circuits and correct wiring connections), as well as the serviceability of the generator.