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MECH1320REMLAP5HW

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 
The waveform that is produced by alternating current looks like a _______________.
a.
sea wave
c.
sawtooth wave
b.
sine wave
d.
square wave
 

 2. 
The rate at which the electrical voltage or current cycle repeats is called ______________.
a.
frequency
c.
recurrence
b.
randomized rate
d.
pulses
 

 3. 
The frequency of the AC electricity in most European countries is _____________.
a.
60 Hz
c.
30 Hz
b.
75 Hz
d.
50 Hz
 

 4. 
The effective value of AC voltage is also called the ___________ voltage.
a.
FMS (Frequency Modulated Sinewave)
d.
All of these
b.
EMS (Electrical Modified Source)
e.
None of these
c.
RMS (Root Mean Square)
 

 5. 
AC electricity flowing in a particular wire is called a _____________.
a.
phase
c.
cycle
b.
field
d.
feed
 

 6. 
When two phases of electricity do not start and end at the same time, they are said to be _____________.
a.
in-phase
c.
repressed
b.
inverted
d.
out of phase
 

 7. 
The amount two electrical waveforms are out of phase is measured in ____________.
a.
volts
c.
degrees
b.
amps
d.
seconds
 

 8. 
The phases of the three-phase power supplied by the power company are _______ degrees out of phase with each other.
a.
60
c.
100
b.
90
d.
120
 

 9. 
Which of the following is a category of AC motors?
a.
Shunt fed
d.
All of these
b.
Compound wound
e.
None of these
c.
Three phase
 

 10. 
Which of the following is a type of single-phase AC motor?
a.
Capacitor-start
c.
Split-phase
b.
Permanent-capacitor
d.
All of these
 

 11. 
The main set of windings in a split-phase motor is called the _____________.
a.
Run windings
c.
Primary windings
b.
Start winding
d.
Secondary windings
 

 12. 
In which of the split-phase motor windings will the current start to flow first?
a.
Run winding
c.
Neither
b.
Start winding
d.
Both
 

 13. 
The device that is used on a split-phase motor to disconnect the start winding when a predetermined speed has been reached is a ____________.
a.
limit switch
c.
pressure switch
b.
centripetal switch
d.
centrifugal switch
 

 14. 
Which of the followingis an advantage of a split-phase motor?
a.
Produces high starting torque
d.
All of these
b.
Produces low starting torque
e.
None of these
c.
Is available in larger sizes
 

 15. 
The speed at which the rotor/shaft of an AC motor must rotate to exactly match the speed of the rotating magnetic field is called ___________.
a.
synchronous speed
d.
All of these
b.
slip speed
e.
None of these
c.
overdrive speed
 

 16. 
The difference bewteen the synchronous speed and the actual speed at which an AC motor will run is called __________________.
a.
slop
d.
All of these
b.
slip
e.
None of these
c.
differential
 

 17. 
Which of the following is an application of a split-phase motor?
a.
Fan
d.
All of these
b.
Centrifugal pump
e.
None of these
c.
Business Machine
 

 18. 
Which of the following is not a method that can be used to reverse the roation of a split-phase motor?
a.
Reverse the power leads
d.
All of these
b.
Reverse the start winding connections
e.
None of these
c.
Reverse the run winding connections
 

Matching
 
 
SEGMENT 1
a.
50 Hz
d.
sine
b.
RMS
e.
instantaneous
c.
Frequency
f.
in phase
 

 19. 

 The waveform that is produced by alternating current is called a _______ wave.
 

 20. 

 __________ is the number of cycles completed in one second.
 

 21. 

 The frequency of AC in the United States is 60 Hz, but is __________ in many other countries.
 

 22. 

 The voltage at any instant during an AC cycle is called _________ voltage.
 

 23. 

 The effective value of AC voltage is also called __________.
 

 24. 

 ________ waveforms reach their positive and negative peaks at the same time.
 
 
SEGMENT 2

Note: Some answers may apply to more than one question.
a.
difference
f.
85
b.
split-phase
g.
two
c.
single-phase
h.
centrifugal
d.
start
i.
three-phase
e.
inductive reactance
 

 25. 

 The two categories of AC motors are ___________ and three phase.
 

 26. 

 ___________ motors are most often used in residential and commercial applications.
 

 27. 

 The most heavily used motors in industry are ________ motors.
 

 28. 

 About _____% of the motors in use in industry are three-phase motors.
 

 29. 

 When power is first applied to a split-phase motor, the current will start to flow in the ________ winding before it does in the run winding.
 

 30. 

 ______________ is the opposition of a coil to alternating current.
 

 31. 

 A rotating magnetic field is developed because of the phase _______ between the start winding and the run winding current.
 

 32. 

 A device called a ________ switch is used to disconnect the start winding from the circuit when a desired speed is reached.
 

 33. 

 A split-phase motor uses single-phase power fed through _______ sets of field windings to produce rotation.
 

 34. 

 The ____________ motor is the most common type used in non-industrial applications.
 
 
SEGMENT 3
a.
start
d.
slip
b.
is not
e.
is
c.
frequency
f.
centrifugal pump
 

 35. 

 One application of a split-phase motor is a ___________, which is often used on an air compressor.
 

 36. 

 Split-phase motors are used when high starting torque __________ (is/is not) required.
 

 37. 

 To reverse the direction of rotation on a single-phase motor, you can either reverse the _______ winding connections or the run winding connections, but not both.
 

 38. 

 The industrial standard for reversing a split-phase motor is to reverse the ________ windings.
 

 39. 

 The synchronous speed of an AC induction motor depends on the _________ of the supplied power and the number of pairs of stator poles.
 

 40. 

 The difference between teh synchronous speed and actual speed on an AC induction motor is called __________.
 



 
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