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 frequency-speed 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:

(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.

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 O/7 4th S Lt

I/2 2nd Spd I/5 N.O.OL O/2 S1 O/5 3rd S Lt

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.