The alternator provides power to the vehicle when the engine is running. The main parts of the generator are the stator and the rotor
On the inside of the stator teeth, there are 18 coils made of insulated copper wire and connected in series of six pieces in three groups.
The groups are connected according to the "star" scheme, three outputs from which go to the rectifier unit.
The rotor is a steel shaft, on the corrugated surface of which two six-pointed steel magnetic cores are pressed.
Between them, an excitation winding made of insulated copper wire is installed on a steel sleeve.
There are two copper slip rings on the rotor shaft, isolated from the shaft and from each other. The ends of the excitation winding are soldered to them.
Copper-graphite brushes are pressed against the slip rings by springs.
When you turn on the mass of the batteries and the instrument and starter switch to position "1" or "2", the current from the battery passes through the brushes and slip rings into the excitation winding.
A magnetic flux is formed around the screws of the field winding, directed by the magnetic cores of the rotor.
When the rotor rotates, the magnetic flux also rotates with it, which crosses the windings of the stator coils.
They generate an alternating current (if the circuit is closed), going to the rectifier unit.
In this block, it is converted into direct current, which goes to all consumers.
The brush holder of the G 273V generator set has a built-in small-sized Ya120M voltage regulator, which is an integrated circuit. It serves to maintain the voltage generated by the generator within the specified limits.
There are four pins on the regulator.
With these terminals, the regulator is installed in the brush holder so that the terminals marked with the letters Ш, Д, В and Р lie on the conductive busbars.
The current-carrying terminal "B" of the voltage regulator is brought out and a wire is connected to it, which feeds the voltage regulation circuit of the generator.
The brush holder also has a make-up resistance, which serves to ensure reliable excitation of the generator at the engine idle speed.
The screw 10 of the seasonal voltage regulation regulator is placed on the brush holder housing. The screw has two positions: "L" - summer, "3" - winter.
When the screw is set to position "3", the voltage maintained by the regulator is 1.5...3.0 V higher than with summer regulation, which is necessary to improve battery charging with an increase in their internal resistance in winter conditions.
The G 288 alternator with electromagnetic excitation is also a three-phase twenty-pole electric machine with a built-in rectifier.
The alternator has the following terminals: "+" - for connecting batteries and load, "-" - for connecting to the vehicle ground, "Ш" - for connecting to the "VK" terminal of the instrument switch and starter and the output "Ш" voltage regulator.
The voltage regulator built into the generator brush holder is assembled according to an integrated circuit and serves to automatically maintain the generator voltage within the specified limits necessary to ensure the charging mode of the battery and the operation of consumers.
The voltage regulator has a seasonal adjustment switch (see fig. 2).
The level of regulated voltage of the generator in switch position L (summer) should be within 27 ... 28 V, in position 3 (winter) - 28.8 ... 30.2 V.
The generator is located in the upper front part of the engine and is attached with two legs to the bracket, and the third one - to the tension bar, it is driven by two V-belts.
The belts are tensioned by moving the generator. The gear ratio of the generator drive is 2.41.
The generator has the following outputs:
- "+" - to connect the battery and load;
- "-" - to connect to the mass of the car;
- В - for connection with the VK output of the instrument switch and starter;
- — plug on the body for phase output.
Generator to be replaced:
- - in case of wear or destruction of the shaft bearings;
- - breakage of covers in case of damage to the windings, as well as in the event of a breakdown of the rectifier unit
Signs of problems:
- - extraneous noise in the operation of the generator or jamming of the shaft;
- - lack of charging current when the engine is running at a crankshaft speed of more than 600 min -1 with a good voltage regulator, battery, generator circuits and normal tension of the drive belts
Removing the generator
Disconnecting car batteries
Raise the cabin to the first position
Disconnect the plug and electrical wires from the generator outputs
We unscrew the coupling bolt of the split support of the generator bracket by 1-2 turns and loosen the stud nut
Unscrew the bolt securing the tension bar and loosen the bolt securing the tension bar to the generator
Turning the generator down, loosen the drive belts
We remove the belts from the pulley grooves and remove the generator by unscrewing the stud nut and unscrewing the coupling bolt
We install the generator on the bracket, put a spring washer on the stud, screw the nut by hand and screw in the coupling bolt
We install drive belts in the pulley streams
We screw, without tightening, the bolts of the tension bar
Moving the generator up, tighten the belts
We tighten the bolts of the tension bar, tighten the nut of the stud that secures the generator to the bracket and the coupling bolt of the split support
A correctly tensioned belt, when pressed on the middle of the largest branch with a force of 39.2 N (4 kgf), should have a deflection of 15-22 mm
Connect the wires to the generator leads and the plug
Lowering the cab
Lead-acid batteries with a voltage of 12 V and a capacity of 190 Ah.
Two batteries are connected in series and provide 24 V.
Each battery consists of six cells interconnected by interconnects with copper inserts to reduce internal resistance.
The brand of batteries dd* for KamAZ vehicles is 6ST-190T (6ST-190A).
Several factories make such batteries. The manufacturer's trademark is applied to the intercell connection between the third and fourth batteries.
We remove the batteries for replacement and recharging or for repairs
Removing the batteries
Disconnecting car batteries
Open the latches securing the battery box cover and remove the cover
Loosen the nuts of the tie rods for fastening the clamping frames of the batteries, remove the frame
Remove battery covers
We unscrew the bolt securing the protective strips and remove the strips
We unscrew the nuts of the bolts securing the tips of the electrical wires to the battery terminals and disconnect the wires
Remove the batteries from the car (remove with an assistant)
Install the batteries in the box
We connect the wire ends to the battery terminals and fasten them with bolts and nuts
The batteries are connected in series
We connect the negative terminal through the battery switch
Conclusions are covered with grease VTV-1
Installing and fixing the protective strips
Install the battery covers and secure them with clamping frames
Installing and securing the battery box cover
Turn on the batteries and check the operation of the batteries by starting the engine