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

Shunt DC

Series DC

Squirrel cage induction

Synchronous

Question 1 of 35

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

Brushless DC motor

Synchronous motor

Three phase induction motor

Squirrel cage motor

Question 2 of 35

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

field poles

rotor

commutator

armature

Question 3 of 35

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

6,900 rpm

2,500 rpm

1,800 rpm

1,140 rpm

Question 4 of 35

5. DC injection braking is used on ________.

the rotors of series motors

the rotors of shunt motors

compound DC motors where a slower stopping method is acceptable

the stationary windings of AC motors

Question 5 of 35

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

240V or more between terminals

50V or more between terminals

15V or more between terminals

600V or more between terminals

Question 6 of 35

7. NEC Article 430 covers ________.

the application and installation of motors

provisions for motor-driven equipment

thermal protection requirements

general information on grounding

Question 7 of 35

8. The wound rotor induction motor is used ________.

when reduced slip is required

to increase power factor

for speed control and to limit starting current

to start low inertia loads

Question 8 of 35

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

in inverse proportion to the speed

in direct proportion to the speed

as the square of the speed

as the cube of the speed

Question 9 of 35

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

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

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

They are small, inexpensive, and powerful.

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

Question 10 of 35

11. 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 11 of 35

12. 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 ________.

armature

controller

rheostat

stator key

Question 12 of 35

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

Safety brakes

Forklifts

Circular saws

Machine tools

Question 13 of 35

14. Slip is best defined as ________.

the speed of the revolving field of the stator

the rated output capacity of a motor

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

any current in excess of the rated current of equipment

Question 14 of 35

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

within sight of the controller location

installed so access is limited to qualified persons

8 feet or more above the floor

guarded

Question 15 of 35

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

Split-phase

Capacitor-start

Synchronous

Question 16 of 35

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

armature current

voltage dropping resistors

the number of poles

full-load torque

Question 17 of 35

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

100%

250%

500%

50%

Question 18 of 35

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

Synchronous speed

FLA rating

Lifting requirements

Circuit rating

Question 19 of 35

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

7 poles

5 poles

2 poles

1 pole

Question 20 of 35

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

Guarded

Drip-proof

Water-cooled

Sealed windings

Question 21 of 35

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

Frame size

Voltage

Current

Frequency

Question 22 of 35

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

Shunt motor

Squirrel cage induction motor

AC motor

Wound rotor induction motor

Question 23 of 35

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

drip-proof

sealed

weather-protected

dust-proof

Question 24 of 35

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

highest starting torque

highest noise level

lowest starting torque

lowest efficiency

Question 25 of 35

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

Induction motors

Alternating current motors

Single-phase motors

Brushless DC motors

Question 26 of 35

27. Horsepower is used to rate the ________.

output capacity of a motor

synchronous speed of a motor

thermal protection of a motor

length of operation of a motor

Question 27 of 35

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

Water-to-air-cooled

Nonventilated

Weather-protected

Explosion-proof

Question 28 of 35

29. How many motor designs does NEMA designate?

Question 29 of 35

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

rated horsepower

power factor

duty rating

rated full-load speed

Question 30 of 35

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

Brushless

Series

Compound

Shunt

Question 31 of 35

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

1.15

2.15

1.5

Question 32 of 35

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

8 to 10 times

5 to 7 times

2 to 4 times

6 to 8 times

Question 33 of 35

34. 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 T2, and L3 to T3.

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

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

Question 34 of 35

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

90° apart

120° apart

180° apart

45° apart

Question 35 of 35

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