Transcript EET 272 Quiz 4 Review

EET 272 Quiz 4 Review
Wound Rotor and Synchronous
Motors
What variable-Speed motor allows you
to change the speed by changing the
number of poles in the motor?
What special 3-phase motor has a
rotor that uses wire wrapped on the
rotor, connected to resistors for
startup?
What is one disadvantage of a
Synchronous Motor?
How many sets of windings in a
Consequent Pole Motor would be
required to have a low and high
speed?
What three-phase induction motor
is designed to run with 0% slip?
When manually starting a Wound
Rotor Motor (WRM), what device is
used to insure the motor is started
with the highest resistance in series
with the Rotor Coils? (It is a very small
answer.)
In what two ways can the rotor of a
Synchronous Motor be Excited? (it can
come from the outside or inside)
How is a WRM accelerated? (What is
increased or decreased? (Don’t fight
the simple answer.))
Aside from running at frequencyspeed over the entire load-range, what
is the other advantage of a
Synchronous Motor and how is it
achieved? (exciting answer)
Why is the starting Torque of a WRM
better than other AC motors?
When starting a Synchronous
Motor, what special windings are
used?
Aside from manual starting and using
time-delay relays, what third method
can be used to automatically start a
WRM? (This question comes up
frequently.)
What device is used with a Synchronous Motor to make
sure the motor does not begin generating voltage on
the Armature when transitioning to full speed? (the
problem is a charge due to the magnetic field and is not
a former president)
Does a Consequent Pole Motor
allow a 4-speed motor with the
same torque at each speed?
Identify the motor and lable the
leads
Identify the motor and lable the
leads
Quiz 4 Lab
Implement the control Circuit of Figure 31-8. Us the LogixPro I/O
simulator using the following I/O:
I/0
Stop
I/3
3rd Spd O/0
M
O/3
2nd S Lt O/6
S3
I/1
1st Spd I/4
4th Spd O/1
1st S Lt
O/4
S2
4th S Lt
I/2
2nd Spd I/5
N.O.OL O/2
S1
O/5
3rd S Lt
O/7
(12/20) Get M and S outputs to close with all timers set to 5 seconds.
(14/20) Use the lights to indicate the motor speed
(16/20) All rungs are commented and all components have symbols
(including the Timers and their contacts).
(18/20) Have the speed indicator flash every ½ second if the motor is
started and accelerating to that speed. Have the light stay on when the
speed is reached.
(20/20) If the Overload Aux Contact opens, alternately flash (every 1
Second) the 1st an 3rd speed lights and the 2nd and 4th speed lights.
Lab Pointers
• Again, you will need to bring your Jump Drive
and LogixPro Disk
• This program is only similar to the program
you will be assigned.
• You will not figure this lab out in 45 minutes,
you will need to work it out in advance.