Contents: General information ↡ Cautions ↡
General information
The engine electrical system consists primarily of the starting and charging systems. Because the functions of these devices are closely related to the engine, they are described separately from the rest of the vehicle's electrical devices, such as lights, instrument cluster, etc. (which are described in chapter 12). A description of the ignition system is given in Part B of this chapter.
The car's electrical system is 12-volt, with a 'minus' on the body.
The battery does not require frequent maintenance; it is charged by an alternator with a rectifier, the generator is driven by a V-belt from the front pulley of the crankshaft.
The engine starter has a pre-engagement mechanism, which is achieved by means of a built-in electromagnetic traction relay. When starting, the traction relay engages the starter drive pinion with the flywheel ring gear before the starter is energized. Once the engine is running, the overrunning clutch prevents the starter rotor from rotating away from the engine until the drive pinion disengages from the flywheel.
Cautions
More details about the design and maintenance of various systems will be given in the relevant sections of this chapter. Although the book provides a description of some repair procedures, the usual method of repair is to replace the faulty element. An owner who does not want to limit himself to simple replacement of elements is recommended to purchase the book "Automobile Electrical & Electronic Systems Manual" ("Guide to the electrical and electronic systems of the vehicle").
When working on the engine's electrical system, precautions must be taken to avoid damaging the semiconductor devices (diodes and transistors) and not injure yourself. In addition to the precautions listed in section "Safety first!", when working with the electrical system, observe the following rules:
Always remove rings, watches, etc. before working on the electrical system. Even with the battery disconnected, a capacitor may discharge through a metal object you have to the ground. This may cause shock or severe burns.
Material taken from a web resource: www.mercedesman.ru
Do not mix up the battery terminals: this can seriously damage components such as the generator, electronic circuits and other components that contain semiconductor devices.
If the engine is started from an external battery using the "cigarette lighter", the batteries must be connected "plus to plus" and "minus to minus" (see "Starting from an external battery"). It is also necessary to connect an external charger to the battery.