During service C (autumn), removing the generator from the engine:

- check the condition of the brush assembly;

- blow the rectifier unit with compressed air;

- check the reliability of fastening the pulley on the generator shaft, tighten it when loosening.

To check the condition of the brush-collector assembly, unscrew the two bolts securing the brush holder in the cover, remove the brush holder and make sure that the brushes move freely in the guides.

If the brush sticks in the brush holder, wipe it and the walls of the guide hole with a rag soaked in gasoline. Remove the brushes, inspect and measure their height. The height of the brush must be at least

8mm from spring to brush base. Replace brushes if necessary. Ras-complete set of brushes is not allowed.

Through the hole in the cover, in which the brush holder is located, slip rings are clearly visible. Inspect the condition of the slip rings and, if necessary, wipe with a rag soaked in gasoline.

If after that burns or dirt are found, then clean the rings with a strip of C100 glass skin, pressing it against the rings through the hole in the cover for the brush holder and turning

generator rotor.

Turn the slip rings if burnt spots are not removed, the rings have an uneven surface, or their wear exceeds 0.5 mm in diameter. The minimum allowable groove diameter of slip rings is 29.3 mm.

Before removing the cover from the side of the slip rings, remove the brushes together with the brush holder in order to avoid damage to the brushes.

Seasonal adjustment is carried out as follows:

- if the outside temperature is stable at 0°C and above, the SPR (seasonal adjustment switch) should be in the SUMMER (L) position - the leftmost position

contact screw PPR, the screw is turned out;

- if the outside temperature is stable at 0°C and below, the PPR must be in the WINTER position (3) - the rightmost position of the PPR screw, the screw is screwed in.

The level of regulated voltage of the generator in the PPR SUMMER position at a load current of 20 A, a rotational speed of (3500 + 200) min -1, ambient temperature (25 + 10)°C and battery switched off

the battery should be within 27 ... 28 V, and in the PPR WINTER position - 28.8 ... 30.2 V.

- remove the ball bearing from the shaft;

- remove the rectifier block from the slip ring side of the cover.

After disassembly, clean the parts and assembly units of the generator from dirt, metal, except for bearings and assembly units containing windings, insulating parts and semiconductor devices, degrease, rinse with gasoline and dry, and wipe the rest with a rag moistened with gasoline. Inspect and replace parts that have mechanical damage. Cracks passing through the hole, wear of the hole more than 17.02 mm and chipped edges of the pulley are not allowed on the pulley more than 2 mm. Check the wear of the belt pulley groove.

The pulley is allowed to be installed if, when installing control rollers with a diameter of 14 mm into the groove, the diameter measured along the rollers is at least 83.5 mm (see Fig. 338).

Eliminate the curvature of the fan blades by straightening and straightening.

If the hole in the bracket for fastening the cover on the slip ring side and the cover on the drive side is more than 10.3 mm, if the hole is worn or oval, ream the hole.

A worn mounting hole for a bearing in the cover on the side of the slip rings to a diameter of more than 35.02 mm, and in the cover on the drive side - more than 47.05 mm, process to a size of 38.0 ... 38.05 mm and 50.00 .. .50.05 mm, respectively, and then press in the repair ring while maintaining the same seat size for the bearing in it.

When assembling the generator, to ensure alignment of the holes for mounting the generator on the engine, insert a tightly fitting rod into them before assembling. After fixing the tie bolts, remove the rod.

After assembly, check by hand the ease of rotation of the shaft and the technical condition of the generator.

Checking the excitation winding of the rotor. Check the condition of the winding with a tester (ohmmeter), while monitoring the reliability of contact between the tips of the measuring wires of the device and the contact rings of the rotor. The resistance value must correspond to the value specified in the technical characteristics of the generator, if the winding does not have short-circuited turns. If there is a break in the winding, then the ohmmeter needle does not deviate. The serviceability of the winding and the reliability of the fit of the brushes to the slip rings can be checked on the stand without disassembling the generator. The verification scheme is shown in fig. 340. When the voltage of the DC power supply is 28 V, connected to the winding plugs, the amount of current consumed must not exceed the value specified in the technical specification of the generator. If there is a break in the winding,ÒÎ the ammeter needle will not deviate.

Determine the short circuit of the excitation winding to ground with a test lamp or a voltmeter under a voltage of 220 ... 250 V. If there is no current for 1 minute, then the winding insulation is in good condition.

If a break is found in the excitation winding, inspect the places where the ends of the winding are soldered to the contact rings and, in case of desoldering, restore

Rice. 340. Connection diagram when checking the technical condition of the generator

The operation of the KamAZ machine has been ensured for many years proper work electrical equipment. During the operation of the machine, various violations are possible. They are associated with gradual wear and tear of the elements. Restoration of KamAZ electrical equipment is carried out in the process Maintenance vehicle.

The composition of the electrical equipment KAMAZ

The electrical equipment of the machine consists of the following links:

• Power supply system.
• Light and sound warning signaling.
• External and internal technical lighting.
• Control-measuring and recording equipment.
• Heating system.
• Starting mechanism.

Power supply system

The power supply is intended for the functioning of the internal and external elements of the car. Electricity is generated by a generator set. The starter is used to start the engine.

The potential scheme of the KamAZ power supply system includes power sources and switches of various types.

Two rechargeable lithium-ion batteries serve to store the generated energy. They are interconnected using a serial assembly.

The generator is connected to the batteries parallel circuit. The negative terminal of the batteries is connected to the machine body through a remote mass switch.

An electric torch device is used to quickly start the engine starter in the cold season. When exposed to it, the generator winding circuit is subject to breaking using an automatic relay.

When the instrument switch button is on, the mass control button is inactive. Automatic blocking prevents the possibility of a sudden disconnection of the mass during the start of the power plant.

The generator is disconnected from the batteries using the switch button. To do this, the instrument switch button is moved to the neutral position. Control over the action of all processes is carried out according to the indication of control lamps.

Wiring diagram for warning lights

Light signals serve to warn drivers of other vehicles about the maneuvers being made. When turning, overtaking and braking, various light signs are used. source luminous flux control lamps and LEDs are used.

Light signaling includes the following elements:

• emergency signaling;
• indication of car and trailer turns;
• brake system alarm;
• external and internal lighting network;
• locking signaling center differential.

Activating the emergency mode button after the starter has started will turn on the front and rear turn indicators. In emergency mode, the indicators light up in a flashing mode.

Light indicators and sound signaling

The flashing indication of pointers is provided by an emergency relay-breaker. The functions of the relay are duplicated by a control lamp on the switch of the alarm unit.

The direction indicators of the transport are switched on and off by the combined switch. The device operates with the instrument switch in the unlocked position. The operation of the entire mechanism is evaluated according to the readings of the relevant sensors.

The light indication of the brake system is activated when the vehicle slows down and stops completely. The braking signal is triggered by closing the pneumoelectric sensor.

The intermediate start relay switches on the rear stop lamps. The signal to turn on the warning light passes through the ammeter. The operation of the ammeter does not depend on the position of the starter button and instrument switch.

The audible alarm is designed to notify the normal operation of the units. The transmission of information is carried out by means of pneumatic and electrosound signals.

The pneumatic signal is turned on by pressing the button on the right side of the outdoor lighting switch. The sound signal is turned on and off by the corresponding button on the transverse frame under the control cabin.

Wiring diagram of the lighting unit

Interior and exterior lighting are designed to operate the vehicle in conditions of poor visibility and at night.

The lighting circuit of the KamAZ car includes the following elements:

• headlights on the control cabin;
• fog halogen headlights;
• front and rear light indicators;
• engine compartment incandescent lamp;
• luggage compartment lighting lamp;
• sleeping lamp;
• a block of lamps for lighting the dashboard;
• plafonds with lamps in the control cabin.

Connection of internal and external lighting is carried out according to a single-wire circuit. The uninterrupted operation of the electrical circuit is provided by fuses with a fusible insert of the PRS-10 type.

Lighting is operated by a combination switch directly connected via an ammeter to the power supply.

Control and measuring electrical circuit

Control and measuring instruments are designed to record the performance of units and assemblies.

All elements of the block are connected in a single-wire parallel circuit. The electrical circuit is closed through the instrument switch and the starting starter. Incandescent lamps and LEDs of various power are used to illuminate and control the light indicators.

Electrical diagram of the heating system

Heating serves to heat the control cabin during the cold season. The air is heated through a radiator. The flow of hot air comes from a reversible electric motor type ME-250.

Depending on the way the contacts are connected, the motor operates in two modes. When connected to the positive pole of the power source, the rotation of the motor shaft occurs in the right direction. When connected to the negative pole - to the left.

Heating is controlled from the cab through a key switch. The uninterrupted operation of components and assemblies is evaluated using control lamps.

Electric circuit for starting the engine

The launcher is designed to start the engine and ensure it stable operation in working mode.

The launch system consists of the following elements:

• starter type ST-142B;
• starter relay;
• starter and instrument switch;
• blocking relay;
• duplicate starter switch;
• external start socket.

ST-142B starter of KamAZ car

The starter is a DC electric motor. The device serves to convert electrical energy from a current source into mechanical energy of rotation of the crankshaft.

The device is made in a hermetic case and has sequential excitation. The unit is equipped with an electromagnetic relay. With the help of an electromagnetic relay, the starter gear engages with the flywheel crown. The start and operation of the starter is accompanied by a flashing of the control lamp.

The first drive of the electric motor is the ratchet mechanism. The ratchet has free play. The second drive is the mass of the engine.

The rated voltage of the ST-1425 type starter is 24 V. The rated power does not exceed 7.7 kW. The gear ratio of the "engine-starter" installation has an indicator of 11.3.

KamAZ car generator

The generator is a unit for converting the mechanical energy of the rotation of the crankshaft into electricity.

The generator consists of a fixed part - the stator and a rotating element - the rotor. The stator consists of a set of metal plates with copper windings. Copper windings are shifted by 120° relative to each other.

The rotor has the form of a steel shaft with a corrugated surface. Two magnetic circuits are pressed onto the shaft. A copper excitation winding is installed between them.

When electricity is supplied from a power source, magnetic fluxes occur in the generator windings. Each stream has the opposite direction. The intersection of multidirectional flows leads to the formation of electricity. Through the brush terminals, the generated electricity is supplied to consumers.

Wiring diagram truck KamAZ has a complex design. It consists of numerous relays, sensors, switches and control lamps. Knowing the basic principles of operation of each element is the responsibility of every vehicle driver.

The device and operation of the generator

The generator is designed to work in a single-wire circuit of the vehicle's electrical equipment. On KamAZ 740 engines, a G288 generator is installed, working with a voltage regulator 11.3702, or a G273-A generator set.

The G288 alternator (Fig. 3.2) with electromagnetic excitation is a three-phase twelve-pole electric machine with a built-in rectifier based on six silicon diodes. The rated power of the generator is 1000 W, the rated voltage is 28 V, the rectified current is not less than 47A. The generator has the following outputs: "+" - for connecting batteries and load, "-" - for connecting to the "mass" of the car, "Ш" - for connecting to the output "VK" of the instrument switch and starter and the output "I /" voltage regulator.

The G273-A alternating current generator set consists of a generator, a rectifier unit built into it and an integrated voltage regulator Ya-120M. Its rated voltage is 24-V, rated power is 800 watts. The “+” terminal is used to connect the battery and the load, and the “B” terminal is used to connect to the “VK” terminal of the instrument switch and starter.

A seasonal adjustment switch is installed on the voltage regulator, which is carried out as follows: if the outside temperature is kept steadily at 0 ° C and above, the screw is turned to the extreme left position, if the outside temperature is set at 0 ° C and below, the screw is turned to the extreme right position .

Rice. 3.3. Genset:
1 - pulley; 2 - fan; 3, 8 - covers; 4 - stator; 5 - rotor; 6 - rotor shaft; 7 - rectifier block; 9 - contact ring; 10- bearing cover; 11 - make-up resistance; 12 - voltage regulator; 13 - brush assembly

Rice. 3.4. Connection diagram of current sources:
O, I, I, III - the position of the instrument switch and starter key; IV- to the switch of the electric torch device; V- to the instrument and starter switch; VI - to the starter solenoid relay; VII - to the electric motors of the heater; VIII - to reversing lights; IX - to the thermal relay of the electric torch device; 1 - generator G272; 2 - contactor; 8-button "ground" switch; 4- switch "mass" VK.860; 5 - rechargeable batteries; 6- starter relay RS530; 7 - ammeter; 8 - instrument and starter switch VK353; 9 - fuse box; 10- relay-regulator PP356; 11-relay for turning off the excitation winding of the generator; H - black; B- white; 3 - green; Zh - yellow; K - red; F - purple; Core brown; O - orange

The generator consists of a stator, a rotor, covers, a rectifier unit, a brush assembly. The excitation winding is placed on a shaft that rotates on two ball bearings. A fan and a two-strand pulley are fixed at one end of the shaft, and slip rings connected to the excitation winding, along which the brushes slide, are fixed at the other end. The cover contains a block of rectifiers and a brush holder.

Figure 53. Generator set G 273V: a) - electrical circuit; b) - cut; c) - voltage switching "summer" - "winter"; 1 - pulley; 2 - fan; 3 - cover on the drive side; 4 - stator; 5 - rotor; 6 - rotor shaft; 7 - rectifier block; 8 - cover from the side of slip rings; 9 - contact ring; 10 - bearing cover; 11 - make-up resistor; 12 - voltage regulator; 13 - brush holder; 14 - seasonal adjustment switch.

The generator has the following outputs:

• "+" - connection of the battery and load;
• B- for connection with the VK terminal of the instrument switch and starter;
• "-" connection to the mass of the power plant;
• plug on the housing for phase output.

The voltage regulator built into the generator brush holder has a seasonal adjustment switch.

The level of regulated voltage of the generator in switch position L (summer) with a load current of 20 A, engine speed (1450 + 100) min-1, ambient temperature (25 + 10) ° C and the included battery must be within 27 ... 28 V, in position Z (winter) - 28.8 ... 30.2 V.

On the engine generator 6582.3701, TU 37.003.1365-88 can be installed.

Figure 53-1. Generator set 3122.3771: a) - electrical circuit; b) incision; 1 - pulley; 2 - fan; 3, 8 - covers; 4 - stator; 5 - rotor; 6 - rotor shaft; 7 - rectifier block; 9 - contact ring; 10 - bearing cap; 11 - make-up resistor; 12 - voltage regulator; 13 - brush holder; C - 2.2 microfarad capacitor.

Attention!

• Do not connect and disconnect the plug connectors and the positive terminal of the generator set while the engine is running and the batteries are on, and also start the engine with the positive wire of the generator disconnected.
• It is not necessary to check the serviceability of the generator set by closing the “+”, “B” and “-” terminals with jumpers to ground and to each other.
• Do not connect the “Sh” terminal of the brush holder, which is accessible through a window in the brush holder casing, with the “+” and “B” terminals of the generator. This leads to failure of the regulator.
• It is impossible to check the health of the electrical circuit and individual wires with a megohmmeter or a lamp, which is supplied with voltage above 26 V, with the generator not turned off.
• Do not check the rectifier unit from a DC source with a voltage of more than 24 V, from an AC source, and also without a signaling device connected in series with the rectifier unit.
• To avoid damage to the voltage regulator when recharging batteries from an external source, disconnect the batteries from the mains.
• When washing engine it is recommended to protect the generator from water ingress.