Electrics & Electronics: Charging, Starting & Lighting

Charging	Charging system	The charging system recharges the battery and supplies electrical energy to all the electrical components in the vehicle.
	Alternator principles	In the alternator a magnetic field rotates and the conductors are stationary. Mechanical energy is converted to electrical energy by electromagnetic induction.
	Alternating current	The value of the induced EMF depends on the strength of the magnetic field, the speed at which the magnet rotates and the number of turns of wire on the stationary coil.
	Alternator components	The main components of an alternator are the stator, the rotor, a slip-ring and brush assembly, a rectifier, two end-frames, and a cooling fan.
	Rectification	Automotive alternators use a three-phase bridge rectifier that has three positive diodes and three negative diodes to rectify the AC current in the three-phase stator windings and produce a DC output.
	Phase winding connections	Two methods of connection can be used for the stator. Star or wye connection and delta connection.
	Rotor circuit	When the ignition is first switched, current flows through the charge indication lamp, the rotor windings and voltage regulator to ground. Current flow through the rotor winding is controlled by the voltage regulator when the engine is running.
	Voltage regulation	The regulator switches rapidly between the 'on' and 'off' conditions, to allow the alternator to maintain an output voltage of approximately 14 volts.
	System operating voltage	As demand for power increases, the charging system must maintain the system voltage even when under load.
	High voltage charging systems	Vehicles have traditionally used 12-volt batteries and a 14-volt charging system, but to meet the increased demand from such high usage systems as electric drives, higher voltage batteries and packs with an appropriately high voltage charging system are necessary.

Alternator construction	Rotor	The rotor is an electro magnet. It consists of a coil of wire wound around an iron core and is pressed on to a steel shaft. It usually has 8 to 12 tapered pole projections.
	Stator	The stator consists of a cylindrical laminated iron core, which carries the three-phase winding in slots on the outside.
	Alternator end frames	The end frames of an alternator are made from aluminum.
	Slip ring & brush assembly	Slip rings are normally copper bands connected to the rotor winding. Brushes allow an electrical connection to the rotating rotor winding.
	Rectifier assembly	Rectifier diodes are mounted on heat sinks. The positive heat sink is insulated from the frame, the negative heat sink is connected to the frame.
	Alternator cooling fan	The fan is a centrifugal type that is mounted on the rotor shaft or drive pulley.

Charging procedures	Checking a charging system	The objective of this procedure is to show you how to check a charging system. Remember to note the voltage readings from the DVOM at all stages of the procedure.
	Removing & replacing an alternator	The objective of this procedure is to show you how to safely remove and replace a vehicle's alternator. The alternator must not be operated with the battery disconnected or the terminals at the back of the alternator disconnected.
	Inspecting & adjusting an engine drive belt	There are two types of drive belts: V-type and Serpentine type. The objective of this procedure is to show you how to inspect and manually adjust engine accessory drive belts.
	Replacing an engine drive belt	Many vehicles require the technician to manually adjust the tension on the belt. Other vehicles have an automatic spring tensioning system. Depending on the system used on the particular vehicle, you should always follow the manufacturer's service instructions. The objective of this procedure is to show you how to remove and replace an engine accessory drive belt.

Starting	Starting system	The starting system consists of battery, cables, starter motor, flywheel ring gear, and the ignition switch.
	Starter motor principles	The starter motor converts electrical energy to mechanical energy and is mounted on the cylinder block in a position to engage a ring gear on the engine flywheel.
	Starter motor construction	The armature is the revolving component of the direct current motor. Brushes maintain contact with a commutator on the armature shaft to conduct current through the windings as the armature rotates.
	Starter magnet types	Normally four stationary field poles are mounted in the outer casing or yoke and these can be electro-magnets or permanent magnets.
	Starter motor engagement	Solenoid operation moves the operating fork and pinion to mesh with the ring gear and causes the plunger contacts to bridge the main starter terminals.
	Commutation	A starter motor armature has a large number of conductor loops and so has many segments to the commutator. Each segment is connected to a loop and is insulated from other segments.
	Switching	The starter motor is brought into operation by a starter switch incorporated as a part of the ignition key. It operates a solenoid which has two functions. To engage the drive pinion with the engine flywheel and connect the battery directly to the starter motor.

Starting procedures	Checking a starting system	The objective of this procedure is to show you how to check a starting system. DVOMs come in many forms. Always follow the specific manufacturer's instructions in the use of the meter or you could seriously damage the meter or electrical circuit.
	Jump-starting a vehicle	The objective of this procedure is to show you how to start a vehicle with a discharged battery using jumper leads and a second vehicle or battery. For safety always connect the leads in the correct order: positive on discharged battery; then positive on charged battery; then negative on charged battery; then negative to a good ground on the vehicle with the discharged battery - away from the battery itself.

Lighting	Lighting system	The lighting system allows the driver to see when driving at night or in poor visibility conditions, and to signal to other drivers.
	Lamps/light bulbs	Most lamps or light bulbs consist of a fine coil of tungsten wire, called a filament, enclosed in a clear glass envelope from which all air has been removed.
	Lamp/light bulb information	All lamps of light bulbs have letters or numbers which indicate the power consumed by the bulb in operation and the nominal operating voltage.
	LED lighting	Light Emitting Diodes, or LEDs, are being increasingly used in automotive lighting applications, because they operate instantly, are more reliable, and last longer.

Types of lights	Stop lights	Stop lights are red lights fitted to the rear of the vehicle which are activated whenever the drive operates the foot brake to slow or stop the vehicle.
	Reverse lights	Reversing lights are white lights fitted to the rear of a vehicle. They provide vision behind the vehicle and warn other drivers that the vehicle will move backwards.
	Indicators	Indicators are amber lights located at the corners of the vehicle. They are pulsing lights that warn other road users of an intended change in direction.
	Headlights	In headlight bulbs the main beam filament is positioned at the focal point of the reflector, and the dip beam filament is placed above and slightly to one side.
	High intensity discharge (HID) lights	High Intensity Discharge or HID lights provide better illumination than other types of lights.
	Driving lights	Driving lights are used to supplement vehicle headlight systems.
	Fog lights	Fog lights are used with other vehicle lighting in poor weather such as thick fog, driving rain or blowing snow.
	Cornering lights	Cornering lights are white colored lights usually fitted into the bumper bar and are designed to provide side light when the vehicle is turning corners.
	Smart lighting	Different lighting technologies can be fitted individually or together to form comprehensive adaptive lighting systems.

Lighting circuits	Park & tail light circuits	Red tail lamps and white park lamps are low wattage lamps that allow the vehicle to be seen by other road users. They are connected in parallel.
	Headlight & dip circuits	Dip or low beam is used in built-up areas or when the driver of an approaching vehicle could be dazzled by the main beam
	Circuit diagrams	Circuit diagrams contain information about wire size, wire color, earth locations and shape and location of electrical connectors around the vehicle.
	Networking & multiplexing	A multiplex network reduces the number of wires in the wiring harness and greater vehicle content flexibility.

Lighting procedures	Checking lighting & peripheral systems	The objective of this procedure is to show you how to check peripheral lighting systems. Be sure to work in a systematic manner or you could miss a faulty bulb or another component.
	Checking & changing an exterior light bulb	The objective of this procedure is to show you how to check and change an exterior light bulb. Before replacing the bulb, check the bulb holder for corrosion. Clean any corrosion with abrasive tape.
	Checking & changing a headlight bulb	The objective of this procedure is to show you how to check and change a headlight bulb. Always make sure that you replace a bulb with one of exactly the same type. Otherwise, change both lights at once, so they always show the same intensity in lumens.
	Aiming headlights	The objective of this procedure is to show you how to use a headlamp adjuster unit to aim headlights. Although the principle of aiming headlights is the same in the majority of cases, the legal rules can differ from region to region. Be sure to check the requirements for your location.

Topic group	Topic	Summary