13.1. General information
Consumers unite to the "plus" power supply a wire, with "minus" – through a car body ("weight"). Such method allows to reduce quantity of wires and to simplify installation.
Moments of an inhaling, N · m
Nuts of fastening of levers of screen wipers of wind and back glasses..... 9–13
Bolt of fastening of the generator..... 38–40
Bolts of fastening of a starter..... 38–64
Fig. 13.1. An arrangement of basic elements of electric equipment and system of ignition in a motor compartment of the car: 1 – rechargeable battery; 2 – starter; 3 – generator; 4 – high-voltage wires; 5 – ignition breaker distributor; 6 – bolt of fastening of the coil of ignition; 7 – spark plug
The system of electric equipment consists of the rechargeable battery, the generator, a starter, consumers of the electric power and electric chains (fig. 13.1).
Headlights, back lamps, fog lights, indexes of turn, devices of illumination of registration plate and illumination of salon belong to system of lighting.
The rechargeable battery is charged from the generator which is put in action by a belt from a pulley of a bent shaft.
The starter represents the electric motor of a direct current of the mixed excitement with the electromagnetic traction relay. At start-up the traction relay enters the leading gear wheel into gearing with a gear wreath of a flywheel before the starter receives a power supply from the rechargeable battery. After launch of the engine the coupling of a free wheeling disconnects a starter anchor from a gear wreath of a flywheel.
It should be noted that during the work with any element of electric equipment of the car for prevention of short circuit and receiving burns always disconnect a wire from the negative plug of the rechargeable battery.
Definition of a source of malfunctions
The electric chain consists of an electric element, switches, the relay, electric motors, safety locks, automatic switches, wires and sockets which connect an electric element to the rechargeable battery and a body. For the help by search of sources of malfunction in system of electric equipment schemes of electric equipment of the car are provided in the management.
Before trying to define a malfunction source, study the corresponding scheme of electric equipment for receiving idea of elements in this chain. The number of possible sources of malfunction can be reduced if to check work of other elements entering this chain. If several elements or chains fail at the same time, perhaps, the safety lock, the general for these chains or elements is faulty, or connection with a body - "weight" is broken.
The weakened or oxidized sockets, violation of contact with a body, the fused safety locks or faulty relays can be causes of defect. Check visually a condition of all safety locks, wires and sockets in the failed chain before starting check of other elements. Use schemes of electric equipment for definition of trailer clips which need to be checked for detection of a source of malfunction.
The main devices necessary for detection of a source of malfunction, the tester or the voltmeter, a control lamp on 12 V, an ohmmeter, the battery and a set of wires with probes, a cap puncture are, it is desirable with the automatic switch or a safety lock which is used for a round of the checked wires or elements.
Besides violation of reliability of connections of wires, in system of electric equipment two more main types of malfunctions – break of a chain or short circuit are possible.
As a result of break the chain is disconnected, current is interrupted, causing shutdown of an element of electric equipment.
For check of an integrity of a chain connect the device for verification of schemes or the voltmeter: one conclusion to the negative plug of the rechargeable battery or the grounded element, another – to contact in the checked chain, it is desirable for the next to the rechargeable battery or a safety lock. The checked site of a chain has to be energized from the rechargeable battery, except for cases when the socket of connection to the battery does not carry current or the safety lock fused (do not forget that some chains of electric equipment join only at turn of a key in the ignition lock in a certain situation).
Include a chain, connect the tester probe to connection, the next to the chain switch on the party of the checked element.
If there is tension (what the control lamp or indications of the voltmeter testifies to), so in the site of a chain between the corresponding connection and the switch there are no gaps.
If the site on which there is no tension is found, so the break of a chain happened between this point and a point of the previous check on which there was tension. The break of a chain is caused by damage or weakening of the socket.
For detection of a source of short circuit execute the following.
Remove the corresponding safety lock and connect conclusions of a tester or the voltmeter to contacts of a safety lock.
Include food in chains, at the same time do not forget that some chains of electric equipment join only at turn of a key in the ignition lock in a certain situation.
If in a chain there is tension (what the control lamp or indications of the voltmeter testifies to), so in a chain there was a short circuit.
If during conducting check there is no tension, and the safety lock still fuses at connection of the same loading, so the loading element failed.
The negative plug of the rechargeable battery is connected to "weight" – a body, the engine or the transmission. Lack of reliable contact or oxidation of fastening can lead to refusal of an element or violation of its work. Do not forget that on many cars "mass" wires between some elements, such as engine/transmission, and a body are used, that is in those places where there is no direct contact between metal elements because of existence of soft rubber fastenings or a paint coat.
For check of reliability of grounding of an element it is necessary to switch-off the rechargeable battery and to connect one of ohmmeter conclusions to reliably grounded element. Connect other conclusion to a wire or connection with a body which needs to be checked. Resistance shown by an ohmmeter has to be equal to zero, otherwise check connection as follows.
If reliability of contact with "weight" raises doubts, investigate connection, remove pollution and smooth out contacts. At assembly tighten fastening of the socket, for prevention of corrosion put a layer of technical vaseline or silicone lubricant.