Question 1

Which of the following statements about how electrical current flow is induced in an alternator is correct?

Accepted Answer

In an alternator, a rotating magnetic field induces a voltage into stationary windings. This is the basic principle of operation for alternators, where mechanical energy is converted into electrical energy through electromagnetic induction.

Question 2

Which of the following defects could result in an undercharged battery?

Accepted Answer

All of the listed defects can result in an undercharged battery. A loose belt can lead to insufficient alternator output, a defective diode trio can prevent proper charging, and a defective voltage regulator can fail to properly control the charging voltage, all contributing to an undercharged battery.

Question 3

How much current flows through the brushes and slip rings of an alternator?

Accepted Answer

In an alternator, the brushes and slip rings are part of the field circuit, which is used to energize the rotor. The current flowing through them is the field current, which is much smaller than the alternator's output current. This field current is controlled to regulate the alternator's output voltage.

Question 4

Which windings in an alternator are connected to the diodes in the rectifier?

Accepted Answer

The stator windings in an alternator are connected to the diodes in the rectifier to convert the alternating current (AC) produced by the alternator into direct current (DC) for the vehicle's electrical system.

Question 5

Technician A says that to perform an AC leakage test,a DMM should be set to auto-range AC with one test lead placed on the alternator insulated terminal,and the other on chassis ground.Technician B says that when performing an AC leakage test,the engine should be run at 1500 rpm.Who is correct?

Accepted Answer

Both technicians are correct. Technician A describes the correct setup for an AC leakage test, which involves using a digital multimeter (DMM) set to measure AC voltage, with one lead on the alternator's insulated terminal and the other on the vehicle's chassis ground. Technician B is correct in stating that the engine should be run at 1500 rpm during the test to ensure that the alternator is producing a charge and any AC leakage can be accurately measured.

Question 6

Technician A says that most current trucks are protected from reverse polarity connections to the electrical system.Technician B says that by connecting a truck electrical system in reverse polarity can destroy an alternator diode bridge and other solid state devices.Who is correct?

Accepted Answer

The answer of Technician A says that most current trucks...

Question 7

What is the maximum acceptable AC leakage specification in a typical truck charging system?

Accepted Answer

The maximum acceptable AC leakage specification in a typical truck charging system is 0.3 V-AC. This is because AC leakage above this level can indicate a problem with the diodes in the alternator, potentially leading to battery drain or other electrical issues.

Question 8

How are the stator windings in a typical truck alternator configured?

Accepted Answer

The answer of How are the stator windings in a...

Question 9

How many diodes are used in a typical 3-phase,full-rectification truck alternator?

Accepted Answer

A typical 3-phase full-wave rectification circuit in a truck alternator uses 6 diodes, with two diodes for each phase to convert AC to DC.

Question 10

What component in an alternator rotates?

Accepted Answer

The rotor is the component that rotates inside an alternator, generating a magnetic field that induces electricity in the stator.

Question 11

Which stator windings are connected in series and have a neutral junction?

Accepted Answer

Wye-wound stators have their windings connected in such a way that they form a 'Y' shape, with one end of each winding connected together at a common point known as the neutral junction. This configuration allows the windings to be connected in series to the neutral point. Delta-wound stators, on the other hand, have their windings connected in a triangle or delta configuration, with no neutral point.

Question 12

Technician A says that a TR type alternator is designed for 12/24-volt chassis electrical system.Technician B says that TR type alternators are commonly used on current,electronically-controlled high compression engines.Who is correct?

Accepted Answer

The answer of Technician A says that a TR type...

Question 13

When an alternator is full-fielded,which of the following temporarily ceases to function?

Accepted Answer

When an alternator is full-fielded, the voltage regulator is temporarily bypassed or ceases to function. This is done to test the maximum output of the alternator, where the field current is maximized, and the voltage regulator does not regulate the voltage.

Question 14

Which of the following conditions will shorten the life of batteries?

Accepted Answer

All of the listed conditions—overcharging, undercharging, and deep-cycling—can shorten the life of batteries by causing various types of damage or stress to the battery cells.

Question 15

How is field current routed through an alternator?

Accepted Answer

The field current in an alternator is routed through the rotor to create a magnetic field. This is achieved using slip rings, which allow the current to pass to the rotating rotor.

Question 16

Technician A says that the best overvoltage protection system in a truck electrical system is the battery bank.Technician B says that zener diodes can be used to suppress voltage spikes that can occur in a truck electrical system.Who is correct?

Accepted Answer

Both technicians are correct. The battery bank can provide overvoltage protection by absorbing excess voltage and preventing it from damaging other components in the electrical system. Zener diodes can also be used to suppress voltage spikes by diverting excess voltage to ground.

Question 17

What specific component on a truck charging system does an AC leakage test evaluate?

Accepted Answer

The AC leakage test specifically evaluates the diode bridge in a truck's charging system. This test checks for any alternating current (AC) leaking through the diode bridge, which should only allow direct current (DC) to pass through. If AC is detected, it indicates a problem with the diodes.

Question 18

What is the function of the diode trio in an internally regulated truck alternator?

Accepted Answer

The diode trio in an alternator rectifies the current produced by the field coil, providing DC voltage to the voltage regulator and rotor field coil.

Question 19

Which of the following statements about the diagnostic practice of full-fielding an alternator is true?

Accepted Answer

All of the statements are true regarding the diagnostic practice of full-fielding an alternator. The procedures for A- and B-type circuit regulated alternators differ, some internally regulated alternators can indeed be full-fielded using a simple tool like a paper clip, and there are some internally regulated charging systems that cannot be full-fielded due to their design or safety features.

Question 20

Which of the following sets of voltage range specifications indicates that a typical truck voltage regulator is functioning properly?

Accepted Answer

The typical voltage range for a properly functioning truck voltage regulator is between 13.5 and 14.1 volts. This range ensures that the battery is being charged efficiently without being overcharged, which aligns with the standard automotive charging system specifications.

Quiz 8: Charging Systems