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

2.15

1.5

1.15

Question 1 of 35

2. DC injection braking is used on ________.

the rotors of shunt motors

the stationary windings of AC motors

the rotors of series motors

compound DC motors where a slower stopping method is acceptable

Question 2 of 35

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

600V or more between terminals

50V or more between terminals

240V or more between terminals

15V or more between terminals

Question 3 of 35

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

Frequency

Frame size

Current

Voltage

Question 4 of 35

5. 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?

Shunt motor

Two loop DC motor

AC motor

Squirrel cage induction motor

Question 5 of 35

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

They are small, inexpensive, and powerful.

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

Question 6 of 35

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

sealed

drip-proof

dust-proof

weather-protected

Question 7 of 35

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

Explosion-proof

Weather-protected

Nonventilated

Water-to-air-cooled

Question 8 of 35

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

6 to 8 times

2 to 4 times

5 to 7 times

8 to 10 times

Question 9 of 35

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

power factor

rated full-load speed

duty rating

rated horsepower

Question 10 of 35

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

armature current

full-load torque

voltage dropping resistors

the number of poles

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 ________.

rheostat

stator key

armature

controller

Question 12 of 35

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

rotor

field poles

commutator

armature

Question 13 of 35

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

Split-phase

Synchronous

Capacitor-start

Question 14 of 35

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

Series DC

Shunt DC

Squirrel cage induction

Synchronous

Question 15 of 35

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

guarded

within sight of the controller location

installed so access is limited to qualified persons

8 feet or more above the floor

Question 16 of 35

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

Compound

Series

Shunt

Brushless

Question 17 of 35

18. Slip is best defined as ________.

the rated output capacity of a motor

any current in excess of the rated current of equipment

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 18 of 35

19. Horsepower is used to rate the ________.

thermal protection of a motor

length of operation of a motor

output capacity of a motor

synchronous speed of a motor

Question 19 of 35

20. NEC Article 430 covers ________.

the application and installation of motors

thermal protection requirements

provisions for motor-driven equipment

general information on grounding

Question 20 of 35

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

FLA rating

Lifting requirements

Circuit rating

Synchronous speed

Question 21 of 35

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

Brushless DC motors

Alternating current motors

Induction motors

Single-phase motors

Question 22 of 35

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

Squirrel cage motor

Synchronous motor

Brushless DC motor

Three phase induction motor

Question 23 of 35

24. How many motor designs does NEMA designate?

Question 24 of 35

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

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

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

Question 25 of 35

26. 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 26 of 35

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

250%

500%

100%

50%

Question 27 of 35

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

Squirrel cage induction motor

AC motor

Shunt motor

Wound rotor induction motor

Question 28 of 35

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

in inverse proportion to the speed

as the cube of the speed

as the square of the speed

in direct proportion to the speed

Question 29 of 35

30. The wound rotor induction motor is used ________.

to start low inertia loads

for speed control and to limit starting current

when reduced slip is required

to increase power factor

Question 30 of 35

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

Safety brakes

Machine tools

Forklifts

Circular saws

Question 31 of 35

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

180° apart

45° apart

90° apart

120° apart

Question 32 of 35

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

Guarded

Sealed windings

Drip-proof

Water-cooled

Question 33 of 35

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

2 poles

5 poles

1 pole

7 poles

Question 34 of 35

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

6,900 rpm

1,800 rpm

1,140 rpm

2,500 rpm

Question 35 of 35

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