Charging Systems

The primary purpose of the charging system on a vehicle is to:

Provide high current only during starting Maintain battery state of charge and supply electrical loads with the engine running Operate the starter motor when the key is turned to START Convert mechanical energy into heat for the heater core

The component that converts mechanical drive from the engine into electrical energy in the charging system is the:

Starter solenoid Alternator Ignition coil Voltage regulator

Modern alternators used in light vehicles are MOST commonly:

DC generators with commutators Three phase AC machines with rectifier diodes Single phase AC machines with slip rings Permanent magnet motors

The magnetic field in a typical automotive alternator is produced by the:

Stator windings Rotor windings supplied through slip rings Rectifier bridge Battery negative cable

The alternator stator windings are most often connected in either:

Series or parallel Delta or wye (star) Open or closed loop Primary or secondary

A rectifier bridge in an alternator is used to:

Change AC output into DC for the vehicle electrical system Increase alternator speed at idle Regulate system voltage to a fixed value Reduce belt noise at high speed

The charging system voltage regulator primarily controls:

Alternator field (rotor) current Stator output current Starter motor current Battery internal resistance

Compared with a traditional externally mounted regulator, an integral (internally mounted) regulator:

Requires longer field circuit wiring Is generally more compact and protected inside the alternator Cannot be controlled by the powertrain control module Eliminates the need for rectifier diodes

A drive belt with automatic tensioner is used so that:

Alternator speed is reduced at high RPM Correct belt tension is maintained as the belt wears The alternator can drive the starter motor Less current is required from the battery

Under normal operating conditions on a 12 V system, charging voltage at the battery with the engine running is typically:

10.5 to 11.0 V 11.5 to 12.0 V 13.5 to 14.8 V 15.5 to 17.0 V

A battery warning lamp that stays ON with the engine running usually indicates:

High charging voltage only Low engine oil pressure Charging system fault or low alternator output Normal operation during warm up

In a lamp controlled indicator circuit, the warning lamp is normally:

Connected directly across the battery posts Supplied by ignition voltage and grounded through the alternator when not charging Connected between the starter and ignition coil Used only as a test light by the technician

Alternator output is rated primarily in:

Watts at idle speed Amperes at a specified speed and temperature Volts at maximum RPM Joules per second at cranking speed

A smaller drive pulley on the alternator compared to the crankshaft pulley will:

Slow the alternator in relation to engine speed Have no effect on alternator speed Increase alternator speed relative to engine RPM Disable the charging system at idle

Temperature compensation in a charging system is necessary because:

Alternator bearings run cooler at higher voltage Battery charging voltage requirements change with temperature Drive belts slip more when hot Regulators cannot sense battery condition

A charging system that is overcharging a battery will MOST likely cause:

Low electrolyte temperature and increased battery life Excessive gassing, loss of electrolyte and plate damage Reduced alternator temperature Lower specific gravity readings in all cells

The three main sections of a conventional alternator are:

Field coil, brushes and pinion Rotor, stator and rectifier assembly Armature, commutator and regulator Drive pinion, solenoid and field shoes

Slip rings on an alternator are used to:

Provide a DC output path from the stator Carry battery voltage directly to the starter Provide a connection to the rotating field winding Limit current in the warning lamp circuit

Which of the following loads places the GREATEST continuous demand on the charging system?

Turn signal lamps Heated rear window and blower motor on high Brake lights Horn

A battery that repeatedly becomes discharged even though the alternator output tests within specification may indicate:

Shorted stator windings Open circuit rotor winding Parasitic drain or battery fault Loose regulator connector causing overcharge

The charging system component that senses system voltage and adjusts field current is the:

Rectifier diode trio Voltage regulator Ignition switch Starter relay

An alternator with worn brushes will MOST likely cause:

Intermittent or no field current and low output High output at idle speed only Mechanical drive failure Permanent battery overcharge

When replacing an alternator, the parts technician must pay close attention to:

Paint colour and pulley guard design only Mounting configuration, pulley type, output rating and regulator connections Wheelbase and axle ratio of the vehicle Type of starter drive used

An alternator freewheel (overrunning) pulley is designed to:

Lock the alternator solidly to the belt drive Reduce belt vibration and noise during rapid engine deceleration Increase charging voltage at idle Allow the alternator to reverse direction at high RPM

The term 'load dump' in a charging system refers to:

Disconnecting a heavily loaded battery from a charging alternator Removing the alternator from the engine Turning all accessories ON at once Shorting the battery terminals together

Computer controlled (smart) charging systems can vary charging voltage in order to:

Match alternator speed exactly to engine speed Reduce engine load and improve fuel economy Prevent operation of lighting circuits Keep battery voltage constant at 12.0 V

A voltage drop test on the positive side of the charging circuit is performed between:

Battery positive post and alternator output terminal with engine running Battery negative post and engine block with key OFF Alternator case and starter housing with engine cranking Battery positive and negative posts with key OFF

Excessive voltage drop in the charging circuit wiring will result in:

Higher voltage at the battery than at the alternator Lower voltage at the battery than at the alternator No effect on battery voltage Only alternator bearing noise

When testing a charging system, high AC ripple at the battery usually indicates:

Loose belt Shorted or open rectifier diodes Frozen battery electrolyte Worn pulley grooves

The alternator cooling fan is required to:

Cool the battery plates Move air through the alternator to dissipate heat Provide extra airflow to the radiator Keep the belt clean

A technician observes that the charging voltage is low at idle but rises into specification at higher RPM. The MOST likely cause is:

Loose or slipping drive belt Shorted stator windings Open warning lamp circuit Weak battery

If the battery connections are reversed on a modern charging system, the MOST likely result is:

Normal operation with slightly lower output Only the warning lamp will not work Damage to diodes, regulator and other electronic components Alternator rotating in the opposite direction

A charging system 'no charge' complaint with the warning lamp ON and a broken drive belt is an example of a:

Mechanical fault Electrical fault Battery manufacturing defect Parasitic draw

A voltmeter on the instrument panel that reads slightly above the centre of the normal band with the engine running usually indicates:

Charging voltage is within acceptable range Battery is overcharged Alternator output is zero Drive belt is slipping

On a vehicle with a separate regulator mounted away from the alternator, poor regulator ground will MOST likely cause:

Stable charging voltage Erratic or high charging voltage Very low alternator output at all speeds Only the warning lamp to fail

When selecting a replacement alternator, increasing the rated amperage output slightly above original equipment is usually:

Acceptable if mounting and connections match Not permitted under any conditions Required for all vehicles with air conditioning Likely to cause immediate regulator damage