Electrical Principles for the Electrical Trades Volume 2 Jim Jenneson 6th Edition- Test Bank
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Sample Test
Chapter 03
Student: ___________________________________________________________________________
|
1. |
Early electric machines were based on
the design of what other machine?
|
|
2. |
What component of an electric machine
supports the rotor shaft and allows it to rotate?
|
|
3. |
Which of the following descriptions
would be suitable for an accessory that has a rating of IP53?
|
|
4. |
Which type of bearing has angled races?
|
|
5. |
Which type of motor mounting has the
whole motor clamped around its body?
|
|
6. |
Which type of motor mounting has the
mount moulded or machined into the end housing?
|
|
7. |
To what do the letters FC refer with
respect to machine cooling?
|
|
8. |
Which type of coupling allows the
connection of loads that are not accurately aligned?
|
|
9. |
Which type of coupling operates on the
same principle as an automobile automatic transmission torque converter?
|
|
10. |
Why are some motors run off load until
they cool down?
|
|
11. |
What are the two main causes of noise
in electric motors?
|
|
12. |
What is the purpose of noise reduction
ducts in electric motors?
|
|
13. |
To what does a siren owe its sound?
|
|
14. |
What is the first step before
disassembling an electric machine?
|
|
15. |
Which component of an electric machine
requires the most maintenance?
|
|
16. |
Which of the following should be done
before the others when an electric motor is disassembled?
|
|
17. |
What is the purpose of witness marks?
|
|
18. |
Which of the following is not checked for
during an initial inspection prior to disassembly?
|
|
19. |
Which of the following is not checked for
during the first run-up after maintenance has occurred?
|
|
20. |
What device can be safely used to
assist in the removal of end covers?
|
|
21. |
What should be done prior to
disassembling a motor to ensure that it is replaced in the correct way?
|
|
22. |
What can be done if a recently
assembled motor does not freely rotate?
|
|
23. |
What precaution should be taken when
replacing a rotor inside a stator?
|
|
24. |
What is the name given to the loss
associated with movement of the rotor?
|
|
25. |
What is the name of the loss associated
with the heating effect of electric current?
|
|
26. |
What is the power input to a 200 V,
single-phase motor if it draws a full load current of 23 A at 0.82 lagging?
|
|
27. |
What is the efficiency of a 4.2 kW
motor if it consumes 5.1 kW of electrical power?
|
|
28. |
Which of the following is not considered a
mechanical loss?
|
|
29. |
What is the power input to a 600 V,
three-phase motor if it draws a full load current of 19 A at 0.866 lagging?
|
|
30. |
What is the power output from a 400 V
three-phase motor if it is running at 2878 RPM, delivering 39 Nm of torque
and drawing 22 A at 0.86 lagging?
|
|
31. |
What are the total losses from a 600 V
three-phase motor if it is running at 2658 RPM, delivering 85 Nm of torque
and drawing 45 A at 0.82 lagging?
|
|
32. |
How much power is drawn from the supply
if a 230 V single-phase motor draws 12 amps at a phase angle of 28o lagging?
|
|
33. |
If a motor draws 2.5 kW from the supply
and it is 86% efficient, what torque will be available at the shaft when it
is running at 1289 RPM?
|
|
34. |
What is the full load efficiency for a
110 V single-phase motor with the following specifications: full load current
= 6.8 A at 0.81 lagging; full load torque = 3.76 Nm; full load speed = 1230
RPM?
|
|
35. |
What is the full load torque for a 500
V three-phase motor with the following specifications: full load current = 42
A at 0.85 lagging; full load speed = 1410 RPM; full load efficiency = 87%?
|
|
36. |
What is the full load speed for a 230 V
single-phase motor with the following specifications: full load current = 11
A at 0.9 lagging; full load torque = 14 Nm; full load efficiency = 84%?
|
|
37. |
What is the full load efficiency of a
400 V three-phase motor that has the following specifications: full load
current = 33 A at 0.89 lagging; full load torque = 57 Nm; full load speed =
2750 RPM?
|
Chapter 03 Key
|
1. |
Early electric machines were based on
the design of what other machine?
|
|
Difficulty: Easy |
|
2. |
What component of an electric machine
supports the rotor shaft and allows it to rotate?
|
|
Difficulty: Easy |
|
3. |
Which of the following descriptions
would be suitable for an accessory that has a rating of IP53?
|
|
Difficulty: Medium |
|
4. |
Which type of bearing has angled races?
|
|
Difficulty: Medium |
|
5. |
Which type of motor mounting has the
whole motor clamped around its body?
|
|
Difficulty: Medium |
|
6. |
Which type of motor mounting has the
mount moulded or machined into the end housing?
|
|
Difficulty: Medium |
|
7. |
To what do the letters FC refer with
respect to machine cooling?
|
|
Difficulty: Medium |
|
8. |
Which type of coupling allows the
connection of loads that are not accurately aligned?
|
|
Difficulty: Medium |
|
9. |
Which type of coupling operates on the
same principle as an automobile automatic transmission torque converter?
|
|
Difficulty: Hard |
|
10. |
Why are some motors run off load until
they cool down?
|
|
Difficulty: Hard |
|
11. |
What are the two main causes of noise
in electric motors?
|
|
Difficulty: Easy |
|
12. |
What is the purpose of noise reduction
ducts in electric motors?
|
|
Difficulty: Medium |
|
13. |
To what does a siren owe its sound?
|
|
Difficulty: Hard |
|
14. |
What is the first step before
disassembling an electric machine?
|
|
Difficulty: Easy |
|
15. |
Which component of an electric machine
requires the most maintenance?
|
|
Difficulty: Easy |
|
16. |
Which of the following should be done
before the others when an electric motor is disassembled?
|
|
Difficulty: Medium |
|
17. |
What is the purpose of witness marks?
|
|
Difficulty: Medium |
|
18. |
Which of the following is not checked for
during an initial inspection prior to disassembly?
|
|
Difficulty: Medium |
|
19. |
Which of the following is not checked for
during the first run-up after maintenance has occurred?
|
|
Difficulty: Medium |
|
20. |
What device can be safely used to
assist in the removal of end covers?
|
|
Difficulty: Medium |
|
21. |
What should be done prior to
disassembling a motor to ensure that it is replaced in the correct way?
|
|
Difficulty: Medium |
|
22. |
What can be done if a recently
assembled motor does not freely rotate?
|
|
Difficulty: Hard |
|
23. |
What precaution should be taken when
replacing a rotor inside a stator?
|
|
Difficulty: Hard |
|
24. |
What is the name given to the loss
associated with movement of the rotor?
|
|
Difficulty: Easy |
|
25. |
What is the name of the loss associated
with the heating effect of electric current?
|
|
Difficulty: Easy |
|
26. |
What is the power input to a 200 V,
single-phase motor if it draws a full load current of 23 A at 0.82 lagging?
|
|
Difficulty: Easy |
|
27. |
What is the efficiency of a 4.2 kW
motor if it consumes 5.1 kW of electrical power?
|
|
Difficulty: Easy |
|
28. |
Which of the following is not considered a
mechanical loss?
|
|
Difficulty: Medium |
|
29. |
What is the power input to a 600 V,
three-phase motor if it draws a full load current of 19 A at 0.866 lagging?
|
|
Difficulty: Medium |
|
30. |
What is the power output from a 400 V
three-phase motor if it is running at 2878 RPM, delivering 39 Nm of torque
and drawing 22 A at 0.86 lagging?
|
|
Difficulty: Medium |
|
31. |
What are the total losses from a 600 V
three-phase motor if it is running at 2658 RPM, delivering 85 Nm of torque
and drawing 45 A at 0.82 lagging?
|
|
Difficulty: Medium |
|
32. |
How much power is drawn from the supply
if a 230 V single-phase motor draws 12 amps at a phase angle of 28o lagging?
|
|
Difficulty: Medium |
|
33. |
If a motor draws 2.5 kW from the supply
and it is 86% efficient, what torque will be available at the shaft when it
is running at 1289 RPM?
|
|
Difficulty: Medium |
|
34. |
What is the full load efficiency for a
110 V single-phase motor with the following specifications: full load current
= 6.8 A at 0.81 lagging; full load torque = 3.76 Nm; full load speed = 1230
RPM?
|
|
Difficulty: Hard |
|
35. |
What is the full load torque for a 500
V three-phase motor with the following specifications: full load current = 42
A at 0.85 lagging; full load speed = 1410 RPM; full load efficiency = 87%?
|
|
Difficulty: Hard |
|
36. |
What is the full load speed for a 230 V
single-phase motor with the following specifications: full load current = 11
A at 0.9 lagging; full load torque = 14 Nm; full load efficiency = 84%?
|
|
Difficulty: Hard |
|
37. |
What is the full load efficiency of a
400 V three-phase motor that has the following specifications: full load
current = 33 A at 0.89 lagging; full load torque = 57 Nm; full load speed =
2750 RPM?
|
|
Difficulty: Hard |
Chapter 03 Summary
|
Category |
# of Questions |
|
Difficulty: Easy |
9 |
|
Difficulty: Hard |
9 |
|
Difficulty: Medium |
19 |
|
EPC 15, 19, 40 |
10 |
|
EPC 55, 56 |
9 |
|
EPC 8, 9, 40 |
19 |
|
Jenneson chapter 3 |
37 |
|
KS01-101A T8 |
2 |
|
KS01-EE102A T12 |
9 |
|
KS01-EG101A T12 |
5 |
|
KS01-EG101A T9 |
12 |
|
KS02-EG006A T3 |
9 |
Chapter 05
Student:
___________________________________________________________________________
|
1. |
What material is the stator core made
from?
|
|
2. |
Where is the stator core located?
|
|
3. |
How many terminals are typically found
in a three-phase induction motor terminal block?
|
|
4. |
To what are the slip rings of a wound-rotor
induction motor connected during starting?
|
|
5. |
What is the main factor that determines
the type of enclosure selected for a three-phase induction motor?
|
|
6. |
What is done to the added resistance of
a wound-rotor induction motor during starting?
|
|
7. |
What must be done to reverse the
direction of rotation of a three-phase induction motor?
|
|
8. |
The magnitude and direction of the
rotating magnetic field at any instant may be determined by:
|
|
9. |
What is the speed of the rotating
magnetic field in a 4-pole machine that is connected to a 50 Hz supply?
|
|
10. |
What is the name given to the speed of
a rotating magnetic field?
|
|
11. |
The induced magnetic field in a
three-phase induction motor:
|
|
12. |
What is the basis for a rotating
magnetic field in a three-phase induction motor?
|
|
13. |
When is the rotor frequency of a
three-phase induction motor at its maximum value?
|
|
14. |
Torque in a three-phase induction motor
is produced by:
|
|
15. |
What is the percentage slip for a
2-pole three-phase induction motor, connected to a 50 Hz supply, when the
rotor speed is 2900 RPM?
|
|
16. |
What is the rotor speed of a 4-pole
three-phase induction motor when it is connected to a 50 Hz supply and it is
operating at 6% slip?
|
|
17. |
The current in the rotor of a wound-rotor
three-phase induction motor occurs due to:
|
|
18. |
What torque is produced by a 4-pole
three-phase induction motor that is connected to a 60 Hz supply when the
rotor speed is 1800 RPM?
|
|
19. |
What is the frequency of the rotor
current for an 8-pole three-phase induction motor that is connected to a 50
Hz supply and operating at 720 RPM?
|
|
20. |
How would the connection of a
three-phase induction motor to a 50 Hz supply affect its operation if it was
designed to operate on a 60 Hz supply?
|
|
21. |
As the load on a three-phase induction
motor increases the:
|
|
22. |
Which type of rotor allows connection
of external resistance to the rotor circuit during starting?
|
|
23. |
Which type of rotor gives a lower
starting current but operates at a reduced speed?
|
|
24. |
What is the effect of embedding the
rotor bars deeper into the rotor core?
|
|
25. |
Why are aluminium rotor bars physically
larger than comparable copper rotor bars?
|
|
26. |
Adding resistance to the rotor circuit
of a three-phase induction motor during starting:
|
|
27. |
As the power output of a three-phase
induction motor increases:
|
|
28. |
Which of the following parameters of a
three-phase induction motor remains fairly constant from no-load to full load
operation?
|
|
29. |
Which of the following factors is not a necessity
for satisfactory operation of a three-phase induction motor?
|
|
30. |
Which of the following is not an indication
of motor overloading?
|
|
31. |
Which of the following is a possible
symptom of single phasing and phase reversal?
|
|
32. |
If one phase winding of a three-phase
induction motor is reversed:
|
|
33. |
What is the name of the condition that
occurs when one line of a three-phase supply is open circuited?
|
|
34. |
What device is required to test for
motor winding continuity?
|
|
35. |
Which of the following tests is a
suitable non-electrical test for finding a faulty coil group in a larger
motor?
|
|
36. |
Which of the following is not evidence that
a motor has been overloaded?
|
|
37. |
What does the flashing light on a
Prufex indicate?
|
|
38. |
Which of the following procedures
should be done first when dismantling a three-phase induction motor?
|
|
39. |
What should be done with separate
subassemblies when dismantling a three-phase induction motor?
|
|
40. |
What is the purpose of a ‘growler’?
|
Chapter 05 Key
|
1. |
What material is the stator core made
from?
|
|
Difficulty: Easy |
|
2. |
Where is the stator core located?
|
|
Difficulty: Easy |
|
3. |
How many terminals are typically found
in a three-phase induction motor terminal block?
|
|
Difficulty: Easy |
|
4. |
To what are the slip rings of a
wound-rotor induction motor connected during starting?
|
|
Difficulty: Medium |
|
5. |
What is the main factor that determines
the type of enclosure selected for a three-phase induction motor?
|
|
Difficulty: Medium |
|
6. |
What is done to the added resistance of
a wound-rotor induction motor during starting?
|
|
Difficulty: Hard |
|
7. |
What must be done to reverse the
direction of rotation of a three-phase induction motor?
|
|
Difficulty: Easy |
|
8. |
The magnitude and direction of the
rotating magnetic field at any instant may be determined by:
|
|
Difficulty: Easy |
|
9. |
What is the speed of the rotating
magnetic field in a 4-pole machine that is connected to a 50 Hz supply?
|
|
Difficulty: Medium |
|
10. |
What is the name given to the speed of
a rotating magnetic field?
|
|
Difficulty: Medium |
|
11. |
The induced magnetic field in a
three-phase induction motor:
|
|
Difficulty: Hard |
|
12. |
What is the basis for a rotating
magnetic field in a three-phase induction motor?
|
|
Difficulty: Hard |
|
13. |
When is the rotor frequency of a
three-phase induction motor at its maximum value?
|
|
Difficulty: Easy |
|
14. |
Torque in a three-phase induction motor
is produced by:
|
|
Difficulty: Easy |
|
15. |
What is the percentage slip for a
2-pole three-phase induction motor, connected to a 50 Hz supply, when the
rotor speed is 2900 RPM?
|
|
Difficulty: Medium |
|
16. |
What is the rotor speed of a 4-pole
three-phase induction motor when it is connected to a 50 Hz supply and it is
operating at 6% slip?
|
|
Difficulty: Medium |
|
17. |
The current in the rotor of a
wound-rotor three-phase induction motor occurs due to:
|
|
Difficulty: Medium |
|
18. |
What torque is produced by a 4-pole
three-phase induction motor that is connected to a 60 Hz supply when the
rotor speed is 1800 RPM?
|
|
Difficulty: Medium |
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