Advanced AC/DC Machines Final

35. When a load is placed on a universal motor, the motor speed _____.

decreases

47. Three-phase motors are _____. a. self- starting b. simple in construction c. less expensive than other motor types of the same HP rating d. all of these

all of these

52. Multiple-speed, 3 phase motors are designed to operate at _____ speeds. a. two b. three c. four d. all of these

all of these

6. Protective clothing provides protection from contact with _____. a. sharp objects b. hot equipment c. harmful materials d. all of these

all of these

24. Shaded-pole motors are commonly _____.

1/2 HP or less

27. A single phase, dual-voltage, split phase motor typically is set for ____V.

115/230

48. During one revolution, a rotor completes _____ electrical degrees in a 6-pole motor.

360

78. Which of the following is an application for a DC shunt motor? a. centrifugal pump b. cooling fans c. woodworking machinery d. all of these e. none of these

All of these

66. The primary purpose of the interpoles is to ________.

Help reduce sparking between the commutator and the brushes

71. The advantage of the series configured DC motor is that it can produce _______.

High starting torque

79. Which of the following statements is NOT true of a DC compound motor?

It has two configurations in which it can be connected.

77. Which of the following statements is FALSE about a separately-excited shunt motor?

It requires only one power supply

63. Which of the following is NOT a rule of safe dress around any electric motor? a. wear safety glasses b. remove loose items c. tie up long hair d. all of these e. none of these

None of these

20. A(n) _____ is used in the converter section to convert AC voltage to DC voltage.

SCR

56. To connect a dual-voltage, wye-connected, 3 phase motor for high voltage, connect L1, L2, and L3 to T1, T2, and T3 and use wire nuts to connect _____.

T4 to T7, T5 to T8, and T6 to T9

97. The English units of motor power are _______.

horsepower

74. A DC shunt motor has the field windings connected ______ with the armature.

in parallel

55. In a variable torque motor, torque and horsepower _____ at higher speed and _____ at lower speed.

increases;decreases

58. Electric motors rely on the principle of ________ to convert electrical power into mechanical power.

inductance

25. When a split-phase motor is first connected to power, the _____.

inductive reactance of the start winding is lower

4. A(n) _____ is a meter that takes temperature measurements without touching an object.

infrared meter

51. To reverse the direction of rotation of a delta-connected, 3 phase motor, _____.

interchange T1 and T3

14. A(n) _____ is an electronic device that changes DC voltage into AC voltage.

inverter

80. The primary advantage of a DC compound motor is _____.

it provides high starting torque

19. The voltage of a coil in a magnetic starter is typically _____ the voltage used by the motor.

lower than

89. The S.I. units of torque are ______?

newton meters

43. The armature is the ____ part of a DC motor.

rotating

85. Instruments designed to measure motor speed are called ________.

tachometers

8. The National Electric Code (NEC) is updated every _____ years.

three

2. A(n) _____ is used to indicate if voltage is present in a circuit, but it does not measure the actual voltage amount.

voltage indicator

57. When troubleshooting a 3 phase motor, if the check for open or shorted windings reads _____, the coil is shorted.

zero

30. A ½ HP capacitor motor requires a capacitor with a value of _____uF.

190/260

22. In a split-phase motor, the main winding current lags the applied voltage by about _____%

20

23. A 1725 rpm motor (1800 rpm synchronous speed) has a slip of approximately ____%.

4

21. The starting torque of a split-phase motor is _____% of the full-load torque.

75-200

50. In a dual-voltage, wye-connected, 3 phase motor, _____ terminal leads are available.

9

28. A(n) _____ degree phase difference is required to produce maximum starting torque in a split-phase motor.

90

16. The major difference between AC and DC generators is that DC generators contain _____.

A commutator

72. If a DC series motor is operated without a load, a condition called ______ will occur.

Runaway

29. The industrial standard for reversing the direction of rotation of a single phase motor is _____. a. reversing the starting winding b. reversing the running winding c. all of these d none of these

all of these

39. The DC compound motor has _____. a. a series field b. a shunt field c. has good regulation speed d. all of these

all of these

42. A reversible universal motor may be reversed by _____. a. using one coil for the forward direction and the other for the reverse direction b. reversing the direction of the current in the field c. all of these d. none of these

all of these

62. Which of the following is a category of electric motors? a. Dc motors b. Univerisal motors c. Ac motors d. all of these e. none of these

all of these

68. Which of the following is a wiring configuration for a DC motor? a. series b. shunt c. compound d. all of these

all of these

82. Which of the following is an application of a DC compound motor? a. conveyors b. punch press c. bending machines d. all of these e. none of these

all of these

99. Which of the following is a motor performance characteristic considered when selecting a motor for an application? a. torque output b. efficiency c. speed d. all of these e. none of these

all of these

70. Which of the following is an application of a DC series motor? a. locomotive b. crane c. hoist d. all the above e. none of these

all the above

41. The three terminals of an SCR are the _____.

anode, gate and cathode

65. Which of the following is not a component of a DC motor?

bearings

32. A split-phase motor has a _____ winding. a. starting b. running c. both A & C d. none of the above

both A & C

9. A class _____ fire extinguisher should be used on electrical fires

c

10. _____ is a signal word that is used to indicate a potentially hazardous situation that, if not avoided, may result in a minor or moderate injury.

danger

31. A shaded- pole motor has _____ starting torque

low

5. A(n) _____ is the application of excessive load to a motor.

overload

34. The field of a DC shunt motor is connected in _____ with the armature.

parallel

54. In a constant torque motor, horsepower changes ____ to the speed.

proportionally

98. Motor efficiency is _______.

ratio of output to input

84. The rotational speed of a motor is measured in units of ________.

revolutions per minute

13. A _____ is a motor control device that provides a gradual voltage increase during AC motor starting and a gradual voltage decrease during stopping.

soft starter

59. The ______ is the stationary winding of the electric motor.

stator

11. The stationary magnetic field is called the _____ in AC motors and the _____ in DC motors.

stator;rotor

3. A(n) _____ is an electrical test instrument that indicates the approximate voltage in an electrical circuit.

voltage tester

49. In a single-voltage, delta connected, 3 phase motor, each phase is _____.

wired end to end to form a closed circuit

53. In a constant horsepower motor, torque _____ as speed increases

decreases

18. The four most common methods of motor control include PLC's, electric motor drives, terminal hard wiring, and _____.

direct hand writing

64. If a motor is too heavy to move, you should _______.

get someone to help

15. Current flow and magnetic field strength are at their _____ value at the positive and negative peaks of the AC sine wave.

max

17. A(n) _____ control circuit is a circuit that provides control functions such as starting, stopping, jogging, direction of rotation control, speed control, and motor protection.

motor

38. The DC series motor _____. a. has the field connected in parallel with the armature b. produces the highest torque of all DC motors c. has good speed regulation d. none of these

none of above

37. Interpoles are used _____. a. to increase sparkling at the brushes b. with shunt and compound motors less than 1/2 HP c. all of these d. none of these

none of these

75. If the shunt field is connected to the same power supply as the armature, the motor is connected in the ________ configuration.

self-excited

81. When a shunt field is connected to a different power supply than the armature, it is called a(n) _______ shunt field.

separately excited

69. A DC _____ motor is one that has the field windings connected in series with the armature.

series

76. The primary advantage of a DC shunt motor is that it provides excellent _________.

speed control