Heavy Duty Truck Systems – Chapter 9 – Lecture Summary & Practice Questions
When does an energized diesel engine cranking motor produce peak torque? - ✔✔A)
At close to stall RPM
Which of the following statements about a starter solenoid pull-in and hold-in windings is true?
- ✔✔B)
pull-in windings use a heavier gauge than hold-in windings
When a diesel engine fails to start after 30 seconds of cranking, what is the recommended cool
down period before cranking the engine again? - ✔✔C)
2 minutes
Which starter solenoid winding has the greatest number of turns? - ✔✔C)
they usually have an equal number of turns
What is the function of the overrunning clutch in a starter drive assembly? - ✔✔A)
prevents starter motor damage from overspeed when the engine starts
Which of the following statements about current flow in a typical truck diesel engine starter
motor are true? - ✔✔D)
all of the above,
field coils are connected in series with the armature windings,
magnetic North and South field windings are wound in opposite directions,
all current flow though the field windings passes through the brushes
Which of the following cranking circuit faults could cause slow cranking? - ✔✔D)
, all of the above,
weak batteries,
high viscosity engine oil,
corroded starter relay connections
A cranking current test on a diesel engine indicates low current draw. Which of the following
faults would NOT be responsible for low current draw? - ✔✔B)
low viscosity engine oil
When performing voltage drop testing through the cranking circuit insulated circuit, what is the
usual maximum voltage drop considered to be acceptable? - ✔✔B)
Less than 0.3 volt
What should be regarded as the maximum cranking time before resting a starter motor and
allowing it to cool? - ✔✔B)
30 seconds
When performing voltage drop testing through the ground circuit of a starter motor you record
a voltage loss of 0.3 V-DC. What should be done first? - ✔✔A)
Nothing, this is within specifications
When the ignition switch is closed, which of the following should happen first? - ✔✔C)
the coil in the starter relay is energized
When measuring voltage loss through a starter connection terminal, what is the maximum
permitted voltage drop? - ✔✔A)
0.3 volts
When does an energized diesel engine cranking motor produce peak torque? - ✔✔A)
At close to stall RPM
Which of the following statements about a starter solenoid pull-in and hold-in windings is true?
- ✔✔B)
pull-in windings use a heavier gauge than hold-in windings
When a diesel engine fails to start after 30 seconds of cranking, what is the recommended cool
down period before cranking the engine again? - ✔✔C)
2 minutes
Which starter solenoid winding has the greatest number of turns? - ✔✔C)
they usually have an equal number of turns
What is the function of the overrunning clutch in a starter drive assembly? - ✔✔A)
prevents starter motor damage from overspeed when the engine starts
Which of the following statements about current flow in a typical truck diesel engine starter
motor are true? - ✔✔D)
all of the above,
field coils are connected in series with the armature windings,
magnetic North and South field windings are wound in opposite directions,
all current flow though the field windings passes through the brushes
Which of the following cranking circuit faults could cause slow cranking? - ✔✔D)
, all of the above,
weak batteries,
high viscosity engine oil,
corroded starter relay connections
A cranking current test on a diesel engine indicates low current draw. Which of the following
faults would NOT be responsible for low current draw? - ✔✔B)
low viscosity engine oil
When performing voltage drop testing through the cranking circuit insulated circuit, what is the
usual maximum voltage drop considered to be acceptable? - ✔✔B)
Less than 0.3 volt
What should be regarded as the maximum cranking time before resting a starter motor and
allowing it to cool? - ✔✔B)
30 seconds
When performing voltage drop testing through the ground circuit of a starter motor you record
a voltage loss of 0.3 V-DC. What should be done first? - ✔✔A)
Nothing, this is within specifications
When the ignition switch is closed, which of the following should happen first? - ✔✔C)
the coil in the starter relay is energized
When measuring voltage loss through a starter connection terminal, what is the maximum
permitted voltage drop? - ✔✔A)
0.3 volts
