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1. How many motor designs does NEMA designate?

Question 1 of 35

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

highest noise level

lowest starting torque

lowest efficiency

highest starting torque

Question 2 of 35

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

voltage dropping resistors

armature current

the number of poles

full-load torque

Question 3 of 35

4. Horsepower is used to rate the ________.

thermal protection of a motor

synchronous speed of a motor

output capacity of a motor

length of operation of a motor

Question 4 of 35

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

5 poles

7 poles

1 pole

2 poles

Question 5 of 35

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

as the square of the speed

in inverse proportion to the speed

in direct proportion to the speed

as the cube of the speed

Question 6 of 35

7. 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 7 of 35

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

Brushless

Series

Shunt

Compound

Question 8 of 35

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

6,900 rpm

1,800 rpm

2,500 rpm

1,140 rpm

Question 9 of 35

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

15V or more between terminals

240V or more between terminals

600V or more between terminals

50V or more between terminals

Question 10 of 35

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

Forklifts

Machine tools

Circular saws

Safety brakes

Question 11 of 35

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

Weather-protected

Explosion-proof

Water-to-air-cooled

Nonventilated

Question 12 of 35

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

Split-phase

Capacitor-start

Synchronous

Question 13 of 35

14. 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 ________.

stator key

controller

rheostat

armature

Question 14 of 35

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

Guarded

Drip-proof

Water-cooled

Sealed windings

Question 15 of 35

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

Synchronous motor

Squirrel cage motor

Three phase induction motor

Brushless DC motor

Question 16 of 35

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

installed so access is limited to qualified persons

guarded

within sight of the controller location

8 feet or more above the floor

Question 17 of 35

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

Induction motors

Single-phase motors

Brushless DC motors

Alternating current motors

Question 18 of 35

19. 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:

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

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

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

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

Question 19 of 35

20. 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

AC motor

Squirrel cage induction motor

Shunt motor

Question 20 of 35

21. 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 21 of 35

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

Lifting requirements

Circuit rating

FLA rating

Synchronous speed

Question 22 of 35

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

commutator

field poles

armature

rotor

Question 23 of 35

24. NEC Article 430 covers ________.

provisions for motor-driven equipment

the application and installation of motors

general information on grounding

thermal protection requirements

Question 24 of 35

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

120° apart

90° apart

180° apart

45° apart

Question 25 of 35

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

250%

100%

500%

50%

Question 26 of 35

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

sealed

dust-proof

weather-protected

drip-proof

Question 27 of 35

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

rated horsepower

rated full-load speed

duty rating

power factor

Question 28 of 35

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

Current

Frame size

Voltage

Frequency

Question 29 of 35

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

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

They are small, inexpensive, and powerful.

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

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

Question 30 of 35

31. Slip is best defined as ________.

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

the speed of the revolving field of the stator

Question 31 of 35

32. 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

6 to 8 times

2 to 4 times

Question 32 of 35

33. 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 33 of 35

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

1.15

2.15

1.5

Question 34 of 35

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

Squirrel cage induction motor

Wound rotor induction motor

Shunt motor

AC motor

Question 35 of 35

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