Electrical Machines and Motors – ATT Test 10 –
Alternators, Motors, and Power Concepts (Q&A
Format)
In a Wye connected alternator, the line voltage is equal to _______ phase voltage x 1.73
In balanced Wye loads, all the resistors are _______ equal
A single-phase alternator physically resembles a _______ single-phase AC motor
In an AC generator, the output voltage across the load in the external circuit reverses polarity
with every _______ of rotation. 180°
CEMF opposes the _______ original conductor magnetic field.
applied voltage.
Which of the following best describes torque? Twisting action
Speed and torque are _______ inversely proportional.
One horsepower is the power rate corresponding to _______ 33,000 ft·lb/min.
,What are the two basic components of a motor? Poles and armature
What is motor efficiency? Ratio of output power to input power.
If a motor is supplied 2500 watts of electrical energy, how much horsepower would it supply?
3.35 hp
Mechanical power is defined in terms of _______ horsepower.
Inefficiency means the _______ input is much greater than output.
100% efficiency means the _______ input power equals output power.
When is torque maximum? Locked condition
Efficiency is measured as a _______ percent.
Electrical power is defined in terms of _______ watts.
CEMF and speed are _______ proportional.
, If a motor is producing 1.5 hp, how much electrical power is it absorbing? (Assume no internal
losses.) 1119 W
What does CEMF stand for? Counter Electromotive Force
As CEMF increases, what happens to conductor speed and torque? Speed increases,
torque decreases
1 horsepower equals how many watts? 746
What is the efficiency rating of a theoretically "perfect" rotating machine? 100%
What is the rate of acceleration? 4 ft/s/s
How is acceleration or deceleration symbolized? a
What is acceleration? A change in velocity
What is the velocity at point B? 4 ft/s
Alternators, Motors, and Power Concepts (Q&A
Format)
In a Wye connected alternator, the line voltage is equal to _______ phase voltage x 1.73
In balanced Wye loads, all the resistors are _______ equal
A single-phase alternator physically resembles a _______ single-phase AC motor
In an AC generator, the output voltage across the load in the external circuit reverses polarity
with every _______ of rotation. 180°
CEMF opposes the _______ original conductor magnetic field.
applied voltage.
Which of the following best describes torque? Twisting action
Speed and torque are _______ inversely proportional.
One horsepower is the power rate corresponding to _______ 33,000 ft·lb/min.
,What are the two basic components of a motor? Poles and armature
What is motor efficiency? Ratio of output power to input power.
If a motor is supplied 2500 watts of electrical energy, how much horsepower would it supply?
3.35 hp
Mechanical power is defined in terms of _______ horsepower.
Inefficiency means the _______ input is much greater than output.
100% efficiency means the _______ input power equals output power.
When is torque maximum? Locked condition
Efficiency is measured as a _______ percent.
Electrical power is defined in terms of _______ watts.
CEMF and speed are _______ proportional.
, If a motor is producing 1.5 hp, how much electrical power is it absorbing? (Assume no internal
losses.) 1119 W
What does CEMF stand for? Counter Electromotive Force
As CEMF increases, what happens to conductor speed and torque? Speed increases,
torque decreases
1 horsepower equals how many watts? 746
What is the efficiency rating of a theoretically "perfect" rotating machine? 100%
What is the rate of acceleration? 4 ft/s/s
How is acceleration or deceleration symbolized? a
What is acceleration? A change in velocity
What is the velocity at point B? 4 ft/s
