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1. Which of the following is true of shaded-pole motors?

They have a larger current, a lower total impedance, and a higher reactance.

They have a low starting torque, a low efficiency, and a high noise level.

They are small, inexpensive, and powerful.

They have a lower line current, are higher efficiency, and are very quiet.

Question 1 of 35

2. In a split-phase motor, how much greater is the starting current when compared to the full-load current?

8 to 10 times

6 to 8 times

5 to 7 times

2 to 4 times

Question 2 of 35

3. How many motor designs does NEMA designate?

Question 3 of 35

4. Which motor should be used for applications that require frequent starts without overheating the motor?

AC motor

Squirrel cage induction motor

Shunt motor

Wound rotor induction motor

Question 4 of 35

5. NEC Article 430 covers ________.

general information on grounding

the application and installation of motors

provisions for motor-driven equipment

thermal protection requirements

Question 5 of 35

6. DC injection braking is used on ________.

the rotors of shunt motors

compound DC motors where a slower stopping method is acceptable

the stationary windings of AC motors

the rotors of series motors

Question 6 of 35

7. A three-phase synchronous motor has three stator windings that are ________.

45° apart

90° apart

120° apart

180° apart

Question 7 of 35

8. The wound rotor induction motor is used ________.

to increase power factor

to start low inertia loads

for speed control and to limit starting current

when reduced slip is required

Question 8 of 35

9. The speed of a three-phase squirrel cage induction motor is controlled by the frequency of the applied voltage and ________.

voltage dropping resistors

full-load torque

armature current

the number of poles

Question 9 of 35

10. Which of the following is located on a motor's nameplate?

Circuit rating

Lifting requirements

FLA rating

Synchronous speed

Question 10 of 35

11. The most common service factor appearing on a motor's nameplate is ________.

1.15

1.5

2.15

Question 11 of 35

12. Any exposed live parts must be guarded if they are operating at ________.

600V or more between terminals

240V or more between terminals

15V or more between terminals

50V or more between terminals

Question 12 of 35

13. For a constant-torque load, the horsepower increases and decreases ________.

in direct proportion to the speed

in inverse proportion to the speed

as the square of the speed

as the cube of the speed

Question 13 of 35

14. A wound rotor motor has been recently put back into service but is now rotating in the wrong direction. After examining the motor, you find that lead L1 is connected to T2, L2 to T3, and L3 to T1. To correct the rotation, you should:

Reverse phase connections between the wound rotor and the resistor bank.

Connect L1 to T1, L2 to T3, and L3 to T2.

Connect L1 to T1, L2 to T2, and L3 to T3.

Connect L2 to T1, L3 to T2, and L1 to T3.

Question 14 of 35

15. The synchronous speed at which a four-pole, 60Hz induction motor operates is ________.

6,900 rpm

2,500 rpm

1,140 rpm

1,800 rpm

Question 15 of 35

16. A three-phase induction motor may have ________.

1 pole

5 poles

7 poles

2 poles

Question 16 of 35

17. The value indicated in rpm on the nameplate is the ________.

duty rating

power factor

rated full-load speed

rated horsepower

Question 17 of 35

18. Due to the absence of any moving electrical contacts, which type of motor should be used where the motor is exposed to flammable dust or gas?

Two loop DC motor

Squirrel cage induction motor

AC motor

Shunt motor

Question 18 of 35

19. Which of the following motors operate on the principle of a rotating magnetic field?

Induction motors

Single-phase motors

Alternating current motors

Brushless DC motors

Question 19 of 35

20. For a given number of poles, which of the following determines the speed of an AC motor?

Frame size

Current

Voltage

Frequency

Question 20 of 35

21. According to NEMA definitions, which of the following is a type of open motor?

Nonventilated

Water-to-air-cooled

Weather-protected

Explosion-proof

Question 21 of 35

22. Slip is best defined as ________.

any current in excess of the rated current of equipment

the rated output capacity of a motor

the difference between the synchronous speed and the speed of the rotor in an induction motor

the speed of the revolving field of the stator

Question 22 of 35

23. Which of the following motors is the best installation choice for an application requiring adjustable speeds?

Synchronous

Split-phase

Capacitor-start

Question 23 of 35

24. According to NEMA definitions, which of the following is a type of totally enclosed motor?

Drip-proof

Water-cooled

Sealed windings

Guarded

Question 24 of 35

25. Which type of motor can be easily reversed by switching two of the leads?

Brushless DC motor

Three phase induction motor

Squirrel cage motor

Synchronous motor

Question 25 of 35

26. Which of the following motors provides constant speed from no-load conditions to full-load conditions?

Series DC

Synchronous

Shunt DC

Squirrel cage induction

Question 26 of 35

27. In a DC series motor, how much of its full-load torque is developed at starting?

100%

500%

250%

50%

Question 27 of 35

28. Horsepower is used to rate the ________.

synchronous speed of a motor

output capacity of a motor

length of operation of a motor

thermal protection of a motor

Question 28 of 35

29. The NEC® requires motor disconnecting means be ________.

guarded

8 feet or more above the floor

installed so access is limited to qualified persons

within sight of the controller location

Question 29 of 35

30. A motor enclosure that minimizes the entrance of rain and airborne particles to the electrical parts is considered ________.

sealed

dust-proof

drip-proof

weather-protected

Question 30 of 35

31. The primary method of varying the speed on a DC shunt motor is to adjust the voltage and current on the field winding or the ________.

controller

stator key

armature

rheostat

Question 31 of 35

32. The capacitor-start motor is the single-phase motor type that has the ________.

highest noise level

highest starting torque

lowest efficiency

lowest starting torque

Question 32 of 35

33. The stationary magnet of a DC motor is represented by the ________.

commutator

field poles

armature

rotor

Question 33 of 35

34. Which of the following are most likely to use dynamic braking?

Safety brakes

Circular saws

Machine tools

Forklifts

Question 34 of 35

35. Which of the following motors is used where the required starting torque is high and speed control is desirable?

Shunt

Series

Brushless

Compound

Question 35 of 35

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