Relevance, Purpose and Tasks
The task of maintaining and repairing a car generator is urgent.
The purpose of the work is to study the maintenance and repair of a car generator.
Tasks:
- to consider the design and operation of automobile generators;
- tp describe the maintenance and basic malfunctions of car generators;
- to study diagnostics of car generators;
- to describe the stages of repair.
Structure of presentation
1. ​Introduction
2.1 The design and operation of automobile generators
2.2 The maintenance and basic malfunctions of car generators
2.3 Diagnostics of car generators
2.4 The stages of repair
3. Findings and Conclusion
4. Answers to questions
Introduction
The generator is designed to provide power to electrical consumers included in
the electrical equipment system and charge the battery while the car engine is
running.
Despite this, malfunctions inevitably occur in the operation of automobile
generators, and some of them lead to the cessation of the transport process.
The design and operation of automobile generators
Any generator contains a stator with a
winding, sandwiched between two covers the front, on the drive side, and the rear, on
the slip ring side. The covers, cast from
aluminum alloys, have ventilation windows
through which air is blown by a fan through
the generator.
Generator structure
● Front cover
● Back cover
● Stator
● Rectifier block
● Rotor
● Pulley
● Brushes
● Slip rings
Maintenance and malfunction of car generators
During daily maintenance of the generator, the presence and magnitude of the charging current is
checked using an ammeter. At average engine speed, the ammeter should show a charging current,
the value of which decreases as the battery charge is restored. With healthy and fully charged
batteries and disconnected consumers, the absence of charging current or low charging current does
not indicate a malfunction of the generator.
During maintenance-1, check the mounting of the generator and the tension of the drive belt. The
belt is tensioned by turning the generator around the lower supports of its mounting.
During maintenance-2, the generator is purged with air, the generator mounting parts and the nut
securing its pulley are tightened, the frequency of the wire tips and their fastening to the terminals of
the voltage regulator are checked.
Basic generator malfunctions and ways to eliminate
them
Cause
Malfunction
Drive belt slipping
Tension the belt, making sure the bearings are in
good condition.
Brushes stuck
Clean the brush holder and brushes from dirt,
check the force of the brush springs
Burnt slip rings
Clean and, if necessary, sharpen slip rings
Open circuit in excitation circuit
Repair open circuit
The rotor touching the stator poles
Check bearings and seating areas. Replace
damaged parts
Voltage regulator malfunction
Replace voltage regulator
Open circuit in the generator-battery circuit
Eliminate break
Diagnostics of car generators
Diagnosing generators comes down to checking the limiting voltage and functionality of
the generator. To perform this operation, you must connect the voltmeter in parallel with
the current consumers. The limiting voltage is checked with current consumers turned
on (sidelights and side lights) and an increased engine speed. It should be in the range of
13.5-14.2 V. The performance of the generator is assessed by the voltage when all
consumers are turned on at a rotation speed corresponding to the full output of the
generator, which should not be lower than 12 V.
Car generator repair
1.
Remove the generator from the engine
2.
Remove the wire plug from the generator
3.
Use a Phillips screwdriver to unscrew the brush holder
screw
4.
Take out the old brushes
5.
Install new ones
6.
Use a Phillips screwdriver to tighten the brush holder
screw
7.
Install the wire plug on the generator
8.
Install the generator on the engine
Findings and Conclusion
Requirements for the generator:
- the output parameters of the generator must be such that in any mode of vehicle movement the
progressive discharge of the battery does not occur;
- the voltage in the vehicle’s on-board network, powered by the generator, must be stable over a wide range
of rotation speeds and loads.
The last requirement is due to the fact that the battery is very sensitive to the degree of voltage stability. Too
low a voltage causes the battery to be undercharged and, as a result, difficulty starting the engine; too high a
voltage leads to overcharging of the battery and accelerated failure.
The principle of operation of the generator and its fundamental design are the same for all cars, differing
only in the quality of manufacture, dimensions and location of the connecting units.
Answers to questions
Thank you for your attention!