Vehicles with engine 4062 are equipped with alternators 9422.3701 and partially 2502.3771

Generator 9422.3701 is a three-phase synchronous electric machine with electromagnetic excitation and built-in silicon diode rectifier.

The generator rotor is driven from the engine crankshaft pulley by a V-ribbed belt.

The stator and generator covers are held together with four screws. The rotor shaft rotates in bearings installed in the covers.

The bearings are lubricated for their entire service life.

The rear bearing is pressed onto the rotor shaft and into the rear cover.

The front bearing is installed on the inside of the front cover and tightened with a washer with four screws.

The back of the generator is covered with a plastic casing.

There are two three-phase windings in the generator stator, made according to the “star” scheme and connected in parallel to each other.

The rectifier is a bridge circuit, it consists of six power limiting diodes or ordinary ones (on part of the generators). They are pressed into two horseshoe-shaped aluminum holder plates.

On one of the plates there are also three additional diodes through which the excitation winding of the generator is powered after the engine is started.

The excitation windings of the generator are located on the rotor.

The winding leads are soldered to two copper slip rings on the rotor shaft. Power is supplied to them through two carbon brushes.

The brush holder is structurally integrated with the voltage regulator.

The voltage regulator is non-separable, in case of failure it is replaced.

To protect the car's electronic equipment from voltage pulses in the ignition system, as well as to reduce radio interference, a capacitor is installed between the “+” terminal and the “ground” of the generator.

The internal windings of the generator and the rectifier unit are cooled by centrifugal fans through the windows in the covers. The 2502.3771 generator has some design differences.

Checking the ZMZ-4062 engine generator on a car

Start the engine, let it run for a few minutes, then bring the crankshaft to 3000 rpm –1 .

Turn on high beam headlights, heated rear window, heater fan, wiper, hazard warning lights.

Measure the voltage at the battery terminals, which should be higher than 13 V.

If this is not the case, then the generator windings are faulty (open or short circuit), the voltage regulator with the brush assembly, the excitation winding rings are oxidized or oily.

In order to make sure that the voltage regulator is working, turn off all consumers except for the side light and measure the voltage at a speed of 1000–1200 min –1 , which should be in the range of 13.5–14.2 B.

The removed voltage regulator can be checked by connecting a test lamp (21-35 W, 12 V) between the brushes. We connect +12 V to the “D 1” terminal, and “minus” to the “ground” terminal.

The lamp should be on, and when the source voltage rises within 13.5–14.2 V, it should go out. If the lamp is on in both cases, the regulator must be replaced.

It is recommended to replace the rectifier unit as an assembly in case of failure of its elements.

It is also possible to replace individual diodes, however, in this case, they will need to be repressed into a holder. This operation requires accuracy and skill.

Cause of malfunction - Remedy

Generator runs, but batteries charge poorly or not at all

  • Loose alternator drive belt tension - Adjust belt tension
  • Voltage regulator damaged - Replace voltage regulator
  • The fastening of the wires on the generator or the battery is loose, the battery terminals are oxidized, the electrical wires are broken - Tighten the terminals, clean the battery terminals, replace the damaged wires
  • Worn or stuck alternator brushes - Replace the brush holder assembly with brushes or restore the mobility of the brushes in the brush holder
  • Excitation winding damage - Check the soldering of the excitation winding leads to the slip rings and, if necessary, repair it or replace the excitation winding
  • One of the diodes of the rectifier unit is broken - Replace the rectifier unit
  • Battery defective - Replace battery

Increased wearof brushes and slip rings

  • Increased slip ring runout - Turn and grind slip rings
  • Oiling the slip rings - Eliminate the cause of the oiling and clean the slip rings with petrol
  • Change the elasticity of the brush springs - Replace the brush holder


  • Voltage regulator defective - Replace voltage regulator
  • Battery defective - Replace battery battery

Increased noiseduring generator operation

  • Generator bearing failure - Replace defective bearings
  • Rotor hitting stator poles - Replace defective bearings
  • Wear of the bearing seat in the generator cover - Replace the generator cover