7
1-54. The ac power aboard ship is usually
distributed as what voltage?
1. 115-volt, three-phase
2. 115-volt, single-phase
3. 230-volt, single-phase
4. 450-volt, three-phase
1-55. The output frequency of an alternator is
determined by what two factors?
1. The number of poles and the number
of phases
2. The number of poles and the speed
of rotation
3. The speed of rotation and the volt-
ampere rating
4. The number of phases and the volt-
ampere rating
1-56. A four-pole, single-phase alternator
rotating at 18M rpm will produce what
output frequency?
1. 60 Hz
2. 400 Hz
3. 1800 Hz
4. 3600 Hz
1-57. Which of the following is the correct
formula for determining the percent of
regulation of an alternator?
1.
2.
3.
4.
1-58. In most alternators, the output voltage is
controlled by adjusting the
1. rotor speed
2. field voltage
3. armature resistance
4. electric load
1-59. When alternators are to be operated in
parallel, which of the following
alternator characteristics must be
considered?
1. Voltage
2. Frequency
3. Phase relationship
4. All the above
1-60. Which of the following motors is/are
types of ac motor?
1. Series
2. Synchronous
3. Induction
4. All of the above
1-61. Which of the following types of motors
is widely used to power small
appliances?
1. Universal
2. Synchronous
3. Polyphase
4. Compound
1-62. A universal motor is a special type of
1. synchronous motor
2. series motor
3. parallel motor
4. polyphase motor
1-63. The number of pole pairs required to
establish a rotating magnetic field in a
multiphase motor stator is determined by
which of the following factors?
1. The magnitude of the voltage
2. The magnitude of the current
3. The number of phases
4. The size of the motor
