The working principle of an automobile generator, how a generator operates
The working principle of an automotive generator is based on the law of electromagnetic induction. Its core task is to convert the mechanical energy of the engine into electrical energy, providing power for the vehicle's electrical system and charging the battery. Here is a detailed explanation of its working process:
How a generator works
Energy source and initial excitation: When the engine is running, it is driven by a belt to rotate the rotor of the generator. In the initial stage of the generator's startup, the battery will supply power to the excitation windings on the rotor, magnetizing the claw poles of the rotor into N and S poles, thereby generating a magnetic field.
Electromagnetic induction generates alternating current: As the rotor rotates rapidly inside the stator windings, this rotating magnetic field continuously cuts through the three-phase windings in the stator. According to the principle of electromagnetic induction, a three-phase alternating induced electromotive force (i.e., alternating current) will be generated in the stator windings.
Rectification: Alternating current to direct current: The alternating current generated by the stator cannot directly supply power to the vehicle's DC electrical system (such as lights, audio, ECU, etc.) and the battery. Therefore, the alternating current flows into the rectifier (usually a three-phase bridge rectifier circuit composed of six or more diodes), converted into direct current.
Voltage regulation and stable output: The voltage regulator is the "brain" of the generator. It continuously monitors the output voltage of the generator. When the engine speed changes causing fluctuations in the output voltage, the regulator adjusts the magnetic field strength by controlling the current size of the excitation windings, ensuring that the output voltage is always stable within the appropriate range of 13.5V to 14.5V, protecting the vehicle's electrical equipment.
Self-sufficiency and charging: When the output voltage of the generator rises to be equal to the battery voltage, the charging indicator light will go out. At this point, the excitation current is no longer supplied by the battery but by the generator itself, entering the normal working state. Eventually, the generated direct current supplies power to all vehicle electrical devices and charges the battery, ensuring sufficient power for the next start.
Collaboration of core components
Rotor: Produces the rotating magnetic field, being the "active party" of electromagnetic induction.
Stator: Contains three-phase windings, being the "passive party" that cuts the magnetic force lines to generate induced current.
Rectifier: The key "converter", converting alternating current into direct current.
Voltage regulator: The key "stabilizer", ensuring a constant voltage.
Brush and slip ring: Introduces current to the rotating rotor excitation windings (in traditional excitation-type generators).
In summary, the automotive generator is a precise mechanical-electrical energy conversion system, with each component working in concert to ensure stable and reliable power supply for the vehicle under various conditions.
There are various symptoms when the generator is broken, mainly including: the dashboard warning light lights up, the lights dim, difficulty starting, abnormal electrical equipment, abnormal noise or odor, etc.
The charging indicator light on the dashboard is constantly on or flashing: After the vehicle starts, the charging indicator light on the dashboard (battery icon or ALT/GEN symbol) remains on or flashes, indicating a fault in the charging system.
Dim or flashing lights of the headlights and dashboard lights: Due to insufficient power supply, the headlights and dashboard lights become dim or change with the accelerator pedal. This is particularly noticeable at night driving.
Difficulty starting or inability to start: When the generator does not generate electricity, the battery is depleted, causing difficulty starting or inability to ignite, and even inability to start again after the engine has shut off.
Continuous depletion of the battery: Even after charging, the battery's power is quickly exhausted, manifested as frequent difficulty starting or the new battery going back to depletion shortly after replacement.
Abnormal operation of electrical equipment: Electric windows, seats, air conditioning, central control screen, etc., operate slowly, lag, or fail due to unstable voltage.
Abnormal noise or odor: When the belt of the generator slips, there is a burning rubber smell; Internal bearings wear out and produce a "buzzing" or "creaking" noise.
The engine operation is unstable: A low output voltage from the generator may cause the engine to shake and have unstable idle speed, thereby affecting the power output.
If you want to know more, keep reading the other articles on this site!
Please call us if you need such products.
Zhuo Meng Shanghai Auto Co., Ltd. is committed to selling MG&MAXUS auto parts welcome to buy.
