Engine start system
The only task of the engine starting system is to ensure that the engine rotates at a speed sufficient to start it.
The starting system consists of a starter, battery, ignition switch, traction relay and connecting wiring.
The starter is a DC motor with mixed excitation and an externally mounted electromagnetic traction relay. The starter consists of a housing (stator) with excitation windings, armatures with overrunning clutch, covers with brush holders and traction relay.
The starter switch is an integral part of the ignition switch and is designed to excite the traction relay installed on the starter. When the starter is turned on, current from the battery begins to flow through the winding of the traction relay. The relay armature is pulled in and the contacts are closed. At the same time, the relay armature through the drive lever ensures the extension of the gear with the overrunning clutch, while the clutch hub rotates on the screw splines of the starter armature shaft and also turns the gear, which facilitates the engagement of the latter with the flywheel ring gear. A current flows through the closed contacts of the traction relay, which feeds the stator and armature windings, and the starter armature begins to rotate together with the hub and freewheel.
After starting the engine, the speed of the gear exceeds the speed of the starter armature. In this case, the freewheel rotates freely, and torque is not transmitted from the engine flywheel to the starter armature shaft. After the ignition key is released, the power circuit of the traction relay windings is opened through the ignition switch, the traction relay armature is pressed back to its original position by a spring, the relay contacts open, and the drive gear disengages from the flywheel ring gear.
The starter with a retractor relay is located parallel to the engine crankshaft and is fixed to the power unit.
When carrying out any work on the engine starting system, observe the following requirements.
- To prevent the starter from failing due to overheating, do not turn it on for more than 15 seconds - wait at least 1 minute before turning it on again. Prolonged cranking of a non-starting engine with a starter leads to accumulation of unburned fuel in the catalytic converter, which is fraught with failure of the latter as a result of fuel ignition during starting.
- The starter motor is connected directly to the battery and careless handling may cause a fire due to a short circuit.
- Always disconnect the negative cable from the battery before servicing the starter.
Charge system
The vehicles in question use an alternator. When installing additional electrical equipment, check that the generator has enough power to provide electricity to new consumers.
The generator is driven by a belt from the crankshaft of the engine.
The generator is a three-phase synchronous electric machine with electromagnetic excitation. A diode rectifier is built into the generator to convert AC to DC. The output voltage is regulated by a built-in regulator. The generator is grounded by weight.
When the generator is running, the electric current flowing through the field winding creates a magnetic flux around the rotor poles. When the rotor rotates, its magnetic poles periodically change under each stator tooth. As a result, the magnetic flux passing through the teeth continuously changes in magnitude and voltage.
This variable magnetic flux creates an electromotive force in the stator winding (EMF). The wedge-shaped shape of the pole pieces of the rotor is selected in such a way that it makes it possible to obtain an EMF curve close to sinusoidal.
At a high rotor speed, when the generator output voltage begins to exceed 13.6-14.6 V, the voltage regulator is locked, and no current passes through the field winding. When the voltage drops, the regulator opens again, allowing free flow of current through the field winding. The higher the rotor speed, the longer the regulator remains locked and, accordingly, the voltage at the generator output decreases more. The process of locking and unlocking the regulator occurs at a high frequency, so the output fluctuations remain almost imperceptible and the generator voltage can be considered constant.
The charging system does not require periodic maintenance, however, the condition of the alternator drive belt, battery and its wiring should be checked and replaced on a regular basis in accordance with the maintenance schedule (see Sections 17 and 18 Chapters 1).
When you turn on the ignition on the instrument cluster, the K / L of the charge should light up for a short time (see chapter "Controls and methods of operation"). If the lamp does not turn off after starting the engine or lights up during its operation, check the condition of the charging system components. Failure to activate the lamp when the ignition is turned on indicates its failure, damage to the corresponding electrical wiring, or a malfunction of the generator (including broken drive belt).
When servicing the generator, take the following safety precautions.
- Do not disconnect the battery or voltage regulator while the engine is running.
- Do not ground the generator excitation terminal or the cable attached to it.
- Do not confuse the order of connecting the voltage regulator wiring.
- Remember that the inclusion of a voltage regulator closed to ground leads to its instantaneous failure.
- Never remove the generator with the battery connected.
- Do not confuse the polarity of the battery connection.
- Never use voltage meters or test lamps connected to a household network when checking on-board electrical equipment (110/220 V).
- When checking the condition of the diodes, do not apply a voltage of more than 12 V to them and do not use megohmmeters, which also have a high output voltage - breakdown of the diodes will lead to a short circuit. Remember that when checking the insulation of the electrical wiring with a megger, you must disconnect all electrical wiring from the generator.
- When charging the battery without removing it from the car, make sure that both wires are disconnected from it; do not confuse the polarity of the charger connection.
- Before carrying out any electrical welding work on the vehicle, do not forget to disconnect the electrical wiring from the generator and battery.
- Any checks of circuits and on-board wiring assemblies should be carried out with the engine off and the battery disconnected.
- Remember that reversing the polarity of any connections carries the risk of permanent damage to the rectifier and generator voltage regulator.