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

50V or more between terminals

240V or more between terminals

600V or more between terminals

15V or more between terminals

Question 1 of 35

2. 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

rheostat

armature

stator key

Question 2 of 35

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

within sight of the controller location

8 feet or more above the floor

guarded

installed so access is limited to qualified persons

Question 3 of 35

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

1,800 rpm

2,500 rpm

1,140 rpm

6,900 rpm

Question 4 of 35

5. NEC Article 430 covers ________.

thermal protection requirements

general information on grounding

the application and installation of motors

provisions for motor-driven equipment

Question 5 of 35

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

rated full-load speed

duty rating

rated horsepower

power factor

Question 6 of 35

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

Shunt

Brushless

Compound

Series

Question 7 of 35

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

Sealed windings

Water-cooled

Guarded

Drip-proof

Question 8 of 35

9. 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 lower line current, are higher efficiency, and are very quiet.

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

They are small, inexpensive, and powerful.

Question 9 of 35

10. The wound rotor induction motor is used ________.

for speed control and to limit starting current

to start low inertia loads

when reduced slip is required

to increase power factor

Question 10 of 35

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

Weather-protected

Explosion-proof

Nonventilated

Water-to-air-cooled

Question 11 of 35

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

Frequency

Current

Voltage

Frame size

Question 12 of 35

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

full-load torque

the number of poles

armature current

voltage dropping resistors

Question 13 of 35

14. How many motor designs does NEMA designate?

Question 14 of 35

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

250%

100%

50%

500%

Question 15 of 35

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

1.5

2.15

1.15

Question 16 of 35

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

rotor

field poles

commutator

armature

Question 17 of 35

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

Synchronous

Capacitor-start

Split-phase

Question 18 of 35

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

1 pole

2 poles

7 poles

5 poles

Question 19 of 35

20. Horsepower is used to rate the ________.

length of operation of a motor

thermal protection of a motor

output capacity of a motor

synchronous speed of a motor

Question 20 of 35

21. 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 21 of 35

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

Shunt motor

AC motor

Squirrel cage induction motor

Wound rotor induction motor

Question 22 of 35

23. DC injection braking is used on ________.

the rotors of series motors

compound DC motors where a slower stopping method is acceptable

the rotors of shunt motors

the stationary windings of AC motors

Question 23 of 35

24. Slip is best defined as ________.

the speed of the revolving field of the stator

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

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:

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

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 T3, and L3 to T2.

Question 25 of 35

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

90° apart

120° apart

45° apart

180° apart

Question 26 of 35

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

Induction motors

Alternating current motors

Brushless DC motors

Single-phase motors

Question 27 of 35

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

Machine tools

Forklifts

Circular saws

Safety brakes

Question 28 of 35

29. 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

AC motor

Two loop DC motor

Squirrel cage induction motor

Question 29 of 35

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

Series DC

Squirrel cage induction

Synchronous

Shunt DC

Question 30 of 35

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

Synchronous speed

Circuit rating

Lifting requirements

FLA rating

Question 31 of 35

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

5 to 7 times

8 to 10 times

2 to 4 times

6 to 8 times

Question 32 of 35

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

in direct proportion to the speed

as the square of the speed

as the cube of the speed

in inverse proportion to the speed

Question 33 of 35

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

weather-protected

dust-proof

drip-proof

sealed

Question 34 of 35

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

highest noise level

lowest efficiency

lowest starting torque

highest starting torque

Question 35 of 35

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