Question

activity 15-1: chapter review
complete the following after carefully studying the corresponding textbook chapter.

1. the ac induction motor consists of a rotor, which revolves inside the ______ housing.

a. fan
b. magnetic
c. stator
d. bearings

1. the ______ consists of soft iron laminations and copper or aluminum bars running through, which connect on the ends.

a. stator
b. fan
c. converter
d. rotor

1. the three-phase induction motor commonly uses a(n) ______ rotor.

a. slow start
b. squirrel cage
c. light weight
d. insulated mesh

1. true or false? to calculate synchronous speed of a stators rotating magnetic field, the frequency and current inside the stator are needed.
2. true or false? rotor current is dependent on the stator.
3. the difference between the speed of the magnetic field rotation and the actual rpm of the rotor is called ______.

a. slip
b. slide
c. drift
d. efficiency

1. the three-phase ______ motors rotor rotates at the same speed as the magnetic field of rotation, and has no slip.

a. synchronous
b. coincident
c. concurrent
d. simultaneous

1. the three-phase ______ motor can vary its speed under a load condition when a variable resistance is connected to the rotor circuit.

a. alternating current
b. wound-rotor
c. sine wave
d. synchro slip

Explanation:

1. AC induction motors have a rotating rotor inside the stationary stator housing.
2. The rotor uses soft iron laminations with conductive bars.
3. Squirrel cage rotors are the standard for 3-phase induction motors.
4. Synchronous speed formula only needs frequency and number of poles, not stator current.
5. Rotor current is induced by the stator's magnetic field, so it depends on the stator.
6. Slip is defined as the difference between magnetic field and rotor speed.
7. Synchronous motors have rotors matching the magnetic field speed, no slip.
8. Wound-rotor motors use rotor circuit resistance to adjust speed under load.

Answer:

1. C. stator
2. D. rotor
3. B. squirrel cage
4. False
5. True
6. A. slip
7. A. synchronous
8. B. wound-rotor