When starting the engine, the main electricity consumer is a starter, the current strength reaches hundreds of amperes, which causes a significant drop in battery voltage. In this mode, consumers are powered only by the battery, which is discharged intensively. Immediately after starting the engine, the generator becomes the main source of power supply.
The generator is a source of constant recharging of the storage battery while the engine is running. If the generator does not work, the battery will quickly discharge. The generator provides the required current for charging the battery and the operation of electrical appliances. After charging the battery, the difference between its voltage and the generator becomes small, which leads to a decrease in the charging current.
When you turn on powerful consumers (such as a rear window heater, headlights) and low engine speed, the total current consumed can be greater than the generator can deliver. In this case, the load will fall on the battery and it will start discharging.
DRIVER AND FIXING OF THE GENERATOR
The generator drive is carried out from the crankshaft pulley by belt drive. The larger the diameter of the pulley on the crankshaft and the smaller the diameter of the generator pulley, the higher the generator speed, respectively, it is able to give consumers more current.
On modern machines, the drive is carried out by a poly-V-belt. Due to its greater flexibility, it allows to install a pulley with a small diameter on the generator and, therefore, to obtain high gear ratios, that is, to use high-speed generators. The tension of the poly-V-belt is carried out by tensioning rollers when the generator is stationary.
DEVICE FOR AUTOMOTIVE GENERATOR
What does the car generator consist of? Any generator contains a stator with a winding, sandwiched between two covers – the front, the drive side, and the rear, on the side of the contact rings. Generators are mounted in the front of the engine with bolts on special brackets. The holding paws and the tensioning eye of the generator are located on the covers.
Caps, cast from aluminum alloys, have ventilation windows through which the air is blown by the fan through the generator. Generators of traditional design are equipped with ventilation windows only in the end part, generators of “compact” design also on the cylindrical part above the frontal sides of the stator winding.
On the cover on the side of the contact rings, a brush assembly is attached, which is integrated with the voltage regulator, and a rectifying unit. The covers are usually strapped together by three or four screws, the stator being clamped between the covers, the seating surfaces of which cover the stator along the outer surface.
The stator of the generator is recruited from steel sheets with a thickness of 0.8 … 1 mm, but is more often performed by “on the edge”. When carrying out the stator package, the yoke of the stator above the grooves usually has projections, in which the position of the layers relative to each other is fixed during the screwing. These protrusions improve the cooling of the stator due to the more developed outer surface.
The need to save metal has led to the creation of a stator package design, recruited from separate horseshoe segments. The binding of individual sheets of the stator package to a monolithic structure is carried out by welding or riveting. Virtually all generators of mass production vehicles have 36 grooves in which the stator winding is located. The grooves are insulated by film insulation or by spraying an epoxy compound.
A feature of automotive generators is the type of pole system of the rotor. It contains two pole halves with protrusions – poles of the beak-like shape of six on each half. Pole halves are stamping and may have protrusions. In the absence of protrusions when pressing on the shaft between the pole halves, a bushing with an excitation winding wound on the frame is installed, with winding being carried out after the bushing is installed inside the frame.