Week #3 - Charging System

Question 1

How many diodes are used in a typical alternator rectifier bridge?

Answer 1

6 (A typical alternator bridge used 6 diodes: some alternators use 2 rectifier bridges)

Question 2

True or False: An alternator rated at130 amps is carbon pile load tested and system voltage drops to 12.6 bolts at a current load of 120 amps. This means that the alternator is okay and can be returned to service.

Answer 2

True

Question 3

What is used to control the current output of an alternator?

Answer 3

A voltage regulator

Question 4

True or False: Intelli-check is an industry acceptable means of testing charging system performance.

Answer 4

True

Question 5

What part of an alternator produces the magnetic field?

Answer 5

Rotor

Question 6

What is the function of slip rings in an alternator?

Answer 6

To conduct current to the rotor

Question 7

When Intelli-check produces a good status rating, the charging system should still be further tested.

Answer 7

False

Question 8

What is the moving component in an alternator?

Answer 8

The rotor

Question 9

What instrument should be used to measure alternator current output?

Answer 9

An ammeter

Question 10

How much horsepower is required to drive a 100 amp alternator?

Answer 10

6-7 horsepower

Question 11

When the term sensing voltage is referred to in alternator operation, which of the following best describes it?

a. 5 volts AC
b. 5 volts DC
c. diode leakage voltage
d. battery voltage

Answer 11

d. battery voltage

Question 12

What is used to perform switching functions in an electronic voltage regulator?

Answer 12

Transistors

Question 13

A typical rotor contains:

a. a pair of poles, one north and one south
b. seven north poles and seven south poles
c. fourteen north poles and fourteen south poles
d. fourteen north poles or fourteen south poles

Answer 13

b. seven north poles and seven south poles

Question 14

What type of diode bridge arrangement is more common in alternators used in heavy truck applications?

Answer 14

Delta

Question 15

True or False: An alternator rated at130 amps is carbon pile load tested and system voltage drops to 12.6 bolts at a current load of 120 amps. The alternator output should test within 10 percent of the rated specification.

Answer 15

True (industry standard is within 10% specification)

Question 16

Why do the brushes in an alternator last much longer than brushes in a DC generator?

Answer 16

They conduct much less current

Question 17

When a carbon pile is used to lad the electrical system to test the charging circuit, how much load should be applied?

a. enough to drop system voltage to 9.6 volts
b. enough to drop system voltage to 12.7 volts
c. one-half the CCA rating of the batteries
d. the rated amperage specification

Answer 17

b. enough to drop the system voltage to 12.7 volts

Question 18

When a diode is in reverse bias, what is happening to current flow through it?

Answer 18

Current is blocked

Question 19

What is used in an alternator to rectify AC to DC?

Answer 19

Diodes

Question 20

How many windings are in a typical alternator stator?

Answer 20

3

Question 21

What component is used to switch field current on and off in an alternator?

Answer 21

A voltage regulator

Question 22

When an alternator is full-fielded, which of the following components is bypassed?

a. the voltage regulator
b. the stator
c. the rotor
d. the slip rings

Answer 22

a. the voltage regulator