The G51 generator is waterproof, operates in parallel with the battery and in conjunction with the PP5I relay-regulator, is designed to supply consumers with electricity and recharge batteries

DC generator, four-pole, protected, shielded, parallel excitation with internal blowing from a fan, cast together with pulley 11.

G-51 generator of ZIL-131 car

In covers 4 and 12 there are two bearings 2 and 10 of closed type (with rubber seals) in which the armature 8 rotates.

There are four reactive-type brush holders on the collector side of the cover.

Rated voltage of the generator is 12 V, power is 450 W.

The generator can be immersed in water, but it cannot work in water due to the strong wear of the brushes.

When a ZIL 131 vehicle crosses a ford more than 0.7 m deep, the generator drive must be turned off.

G-51 generator diagram

The electrical circuit of the generator is shown in fig. 2.

The negative brushes are installed in non-insulated brush holders and connected to the generator housing.

Positive brushes are installed in insulated brush holders and connected to the "I" terminal.

Two ends of two pairs of excitation coils of the generator are connected to the terminals Ш, and the other two ends of these coils are connected to the housing.

Conclusions Ш1 and Ш2 and output 51 go inside a special shielding box attached to the case.

The rotation of the generator is right-handed when viewed from the drive side.

To enable the generator to work after being in the water, improved insulation impregnation and special materials were used on it; other parts have improved corrosion-resistant protective coatings.

Special holes are provided in the protective tape for water drainage.

The generator is attached with two legs to the brackets, which, in turn, are fixed to the compressor base.

The rear bracket has oval holes to allow it to be moved to adjust the gap between the brackets and legs.

The third leg is designed to attach the generator to the tension bar, with which the tension of the drive belt is adjusted.

For ease of adjustment, the slot in the bar is made not from the side of the generator, but from the side of the compressor base.

The armature shaft bearings have integral rubber seals and operate without lubrication.

Observation of the operation of the generator is carried out on the car using a warning lamp installed on the instrument panel.

A warning lamp is connected between the ignition switch and the generator's "I" terminal.

When the ignition is turned on and the engine is not running, the lamp should burn at full intensity.

After starting the engine, as the number of revolutions of the crankshaft increases, and, consequently, the number of revolutions of the generator armature, the lamp glow decreases.

When the generator develops normal voltage, the lamp goes out completely.

If the warning light comes on at 900-1000 rpm and above, this indicates a malfunction of the alternator or governor relay.

If the lamp does not light up when the ignition is turned on, then it is burned out and must be replaced immediately.

The wires from the relay-regulator must be connected to the generator output terminals in strict accordance with the general electrical equipment diagram.

To the ends of the wires, the parts of the plug connector and the fastening of the shielding braid (plug, conical and rubber bushings, special nuts) installed on each generator and relay-regulator are preliminarily attached.

Generator G-51 ZIL-131

The connection of wires to the plugs of the generator and relay-regulator plugs is shown in fig. 3 and produced like this:

  • - strip the end of the wire for a length of 20 mm, put a nut 1 and an outer conical sleeve 3 on the shielding braid of the wire;
  • - pull the shielding braid onto the inner conical sleeve 2, which is pinched with the help of the sleeve 3.

The legs of the braid are bent and connected to the sleeve 2.

In this case, it is necessary to carefully cut off the protruding veins of the shielding braid so that these veins do not touch the conductive parts, then a rubber sleeve 8 attached to the connector is put on the end of the wire.

On the contact plug, unscrew the nut 5, remove the washer 7 and the cup 4.

Insert the stripped end of the wire into the hole of the plug 6 from the side of the insulating collar and wrap the end of the wire once around the threaded part of the plug, onput on the cup 4, the washer 7 and tighten the nut 5 tightly.

When threading the wires, make sure that individual wires do not protrude from under the cup 4, otherwise they can cause a short circuit.

Generator specifications

Rated voltage in - 12

Rated current in A - 35

The number of revolutions of the generator shaft per minute at which a voltage of 12.5 V is reached at a temperature of 20 ° C:

  • at zero current - 1450
  • at zero current

No-load current (with a voltage at the terminals of 12 V) when the generator is running in engine mode, in A, not more than 12

The pressure force of the brush springs on the brushes in G - 800—1300

Care of the generator

Check the drive belt tension daily.

At first maintenance:

  • 1. Clean the outer surface of the generator from oil and dirt.
  • 2. Check the reliability of fastening the generator to the bracket, as well as to the tension bar.

When fixing the generator to the engine, please note that the rear bracket of the generator has oval slots for the bolts that secure the bracket to the base of the air compressor.

Thanks to this, the brackets can be drawn to the legs of the generator covers without any gap.

When installing the generator, before tightening the bolts securing the generator to the brackets, it is recommended to loosen the rear bracket bolts, tighten the generator mounting bolts and then fully tighten the rear bracket bolts.

  • 3. Check the tightening of nuts, contact plugs; To do this, unscrew the special union nuts of the connector, remove the plugs and check the tightness of the plugs.
  • If the forks wiggle, tighten the nuts.

When tightening and unscrewing the union nuts of the connectors, it is necessary to prevent the twisting of the shielded wires along the nut, as this leads to the destruction of the shielding braid, as well as to a violation of the electrical contact between the wire braid and the body.

Tighten union nuts only by hand.

Pliers or other tools should only be used as a last resort; at the same time, damage to the fittings and the union nuts themselves must not be allowed.

At the second maintenance (5000-6000 km) and after each fording:

  • 1. Check the operation of the brush assembly, for this you need to remove the protective tape of the generator, inspect the brushes and the collector and make sure that the brushes move freely in the brush holders and fit well to the collector.
  • 2. Check the brush spring pressure with a dynamometer.

The clamping force of the brush springs must be at least 0.6 kg. The height of the brushes must be at least 14 mm.

Worn out brushes should be replaced with new ones. New brushes must be lapped onto the commutator.

Lapping new brushes to the commutator is done as follows: insert a strip of fine glass skin with a width equal to the length of the commutator between the brush and the commutator, to do this, pull the brush holder lever with a wire hook and lift the brush.

The strip should cover at least half of the collector circumference (greater than 180°) and be facing the brushes with its working side.

Then you need to release the brushes and drag the strip against the direction of rotation of the armature until the brushes fit well on the commutator.

When moving in the direction of rotation, the brushes must be raised.

  • 3. Check the condition of the working surface of the collector; it should be clean and without burning.

If there are dirty or burnt surfaces, wipe the collector with a clean cloth soaked in gasoline.

During normal operation of the generator, the working surface of the collector looks like a polished surface.

Do not mix a burnt collector that has a matte black color at the running edge of the plates with an unburned collector that has a shiny light brown or blue working surface.

The shiny surface of the commutator should not be cleaned, as this surface improves the performance of the brushes.

If dirt or burns cannot be removed with a rag soaked in gasoline, it is necessary to clean the collector with fine glass sand, rotating the anchor by hand.

It is not allowed to use sandpaper.

If the burn is not cleaned with glass sandpaper, you need to remove the generator from the engine, disassemble it and grind the collector until a clean, smooth surface is obtained.

After turning, it is necessary to clean the collector, i.e., select the insulation between the collector plates to a depth of 0.8 mm with a sharp hacksaw blade sharpened to the insulation depth.

The cleanliness of processing after turning should be at least "7".

G-51 generator collector insulation sampling

When cleaning, care must be taken to ensure that the insulation is selected across the entire width, as indicated in fig. 4.

After cleaning, remove the burrs with fine glass sandpaper.

Warning 2: disassembly and assembly of the generator is carried out only after the expiration of the warranty period (25,000 km) in a specialized workshop that has all the necessary tools and measuring instruments.

Removing the protective tape for preventive maintenance is not disassembly.

  • 4. Blow out the generator with compressed air or a dust pump.
  • 5. Check and, if necessary, tighten the tie rods, the alternator pulley nut.


Repair of the crankshaft consists of regrinding the main and connecting rod journals to the next repair size

The hydraulic clutch release (Fig. 1) of vehicles of the UAZ-31512 family consists of a suspended pedal 19, a master cylinder 5, a hydraulic pipe 4, a hydraulic hose 24 and a working cylinder 25