Question 1

Which of the following describes the role of a rectifier in an alternator?

Accepted Answer

A rectifier in an alternator converts alternating current (AC) into direct current (DC).

Question 2

Technician A says that the Delco-Remy Intelli-check instrument can pin-point difficult to diagnose,charging circuit problems.Technician B says that an Intelli-check test procedure produces one of 5 status outcomes after testing.Who is correct?

Accepted Answer

The answer of Technician A says that the Delco-Remy Intelli-check...

Question 3

Technician A says that a Delco/Remy 33/34 SI alternator can only be driven clockwise (CW).Technician B says that to restore residual magnetism in an alternator with an R or I terminal,the ground terminal should be momentarily connected to battery ground.Who is correct?

Accepted Answer

Technician B is correct because to restore residual magnetism in an alternator with an R or I terminal, the ground terminal should be momentarily connected to battery ground.

Question 4

Technician A says that to perform a maximum output test on a typical heavy-duty truck charging circuit,the engine should be run at 1500 rpm.Technician B says that alternator rpm is typically at least three times engine rpm.Who is correct?

Accepted Answer

To perform a maximum output test on a heavy-duty truck's charging circuit, running the engine at 1500 rpm is a common practice because it ensures the alternator is operating at a sufficient speed to produce its maximum output. Technician B is also correct because the pulley ratio between the engine and the alternator is designed such that the alternator spins at a higher RPM than the engine, often at least three times the engine's RPM, to ensure it generates enough power even at lower engine speeds.

Question 5

Technician A says that Intelli-check is best used as a first-level diagnostic tool.Technician B says that if Intelli-check illuminates one of the four failure indicator LEDs,it would be good practice to have a technician skilled in electrical systems to check the system before replacing components.Who is correct?

Accepted Answer

Intelli-check is indeed designed to be a first-level diagnostic tool, making Technician A correct. It provides initial insights into system health. Technician B is also correct because if Intelli-check indicates a failure, it's prudent to have a skilled technician further diagnose the issue before replacing parts, to ensure the root cause is addressed.

Question 6

What amperage ratings can be produced by a Delco/Remy 33/34 SI alternator?

Accepted Answer

The answer of What amperage ratings can be produced by...

Question 7

Technician A says that a Delco/Remy 55 SI alternator rated at 420 amps is often used in motor coach applications.Technician B says that a Delcotron 33/34 SI can be rated as high as 300 amps.Who is correct?

Accepted Answer

Both Technician A and Technician B are correct. The Delco/Remy 55 SI alternator is indeed used in high-demand applications such as motor coaches and can be rated up to 420 amps. The Delcotron 33/34 SI alternator can also be rated up to 300 amps, which is suitable for applications requiring a high electrical load capacity.

Question 8

How many windings should a typical truck alternator stator have?

Accepted Answer

A typical truck alternator stator has three windings. This configuration allows for the generation of three-phase AC electricity, which is then rectified to DC to charge the vehicle's battery and power its electrical systems.

Question 9

Technician A says that a 100 amp alternator can draw as much as 7 horsepower from the engine.Technician B says that an alternator is switched in and out of its effective cycle by the voltage regulator.Who is correct?

Accepted Answer

Technician A is correct because a 100 amp alternator can indeed draw a significant amount of horsepower from the engine, with estimates around 5 to 10 horsepower, making 7 horsepower a reasonable figure. Technician B is also correct because the voltage regulator controls the alternator's output by switching its field circuit on and off, effectively regulating the alternator's charging cycle.

Question 10

Which of the following best explains how an alternator is driven by truck engine at a higher speed than engine rpm?

Accepted Answer

The drive pulley to alternator pulley ratio is what allows the alternator to be driven at a higher speed than the engine rpm. By having a smaller pulley on the alternator than on the drive pulley attached to the engine, the alternator can spin faster than the engine's rpm, generating the necessary electrical power efficiently.

Question 11

When testing a Delcotron 33/34 SI alternator at an ambient temperature of 80 degrees Fahrenheit,what would be a within specification field current draw?

Accepted Answer

The Delcotron 33/34 SI alternator typically has a field current draw specification of 5.5 to 9 amps at an ambient temperature of 80 degrees Fahrenheit.

Question 12

Technician A says that when the load on a truck electrical system is minimal,the alternator will freewheel,reducing the parasitic load on the engine.Technician B says that a typical truck alternator may be cycled by the voltage regulator hundreds of times per second.Who is correct?

Accepted Answer

Technician A is correct because modern alternators can indeed reduce their load on the engine when the electrical demand is low, improving fuel efficiency. Technician B is also correct because the voltage regulator can rapidly adjust the alternator's output to maintain a consistent voltage level, which may involve cycling the alternator's activity many times per second to respond to the changing electrical demands of the vehicle.

Question 13

If you do not apply an electrical load to the batteries when full-fielding an alternator,which of the following could result?

Accepted Answer

When full-fielding an alternator without applying an electrical load to the batteries, high voltage spikes can occur, potentially causing damage to both electrical and electronic components.

Question 14

Which of the following alternator failures could result in undercharging?

Accepted Answer

All of the listed failures, including a shorted stator winding, an open stator winding, and a grounded rectifier, can lead to an alternator undercharging the battery. Each of these issues disrupts the normal flow of electricity, reducing the alternator's ability to charge the battery.

Question 15

When a diode is used in an AC circuit for half-wave rectification,which of the following should be true?

Accepted Answer

In half-wave rectification, a diode is used to conduct current during one half of the AC cycle (either positive or negative, depending on the orientation of the diode) and block current during the other half. When the diode is forward biased, it allows the positive half of the AC sine wave to pass through, effectively conducting during this phase. This process does not scramble the frequency, square the wave, or block the positive half if the diode is oriented to conduct the positive half.

Quiz 8: Charging Systems