AC Machines

Question 1

referred to as alternators

Answer 1

AC generator

Question 2

almost all electric power for homes and industries is supplied by this

Answer 2

alternators

Question 3

consists of constant magnetic field, conductors that rotate across the magnetic field, and some means to connect the conductors as they are rotating

Answer 3

AC generator

Question 4

Types of Alternator

Answer 4

DC alternator, AC alternator

Question 5

produces alternating current that is converted to direct current; found on smaller aircraft

Answer 5

DC alternator

Question 6

produces a great deal of power, typically found on larger aircraft

Answer 6

AC alternator

Question 7

You can also define an alternator depending on its ______ and ______.

Answer 7

stator, rotor

Question 8

similar in construction from DC generators; setup is typically found in alternators that have low power rating

Answer 8

Revolving-armature type alternator

Question 9

has both a stator and a rotor; armature is connected directly to the load without sliding contacts in the load circuit

Answer 9

Revolving-field type alternator

Question 10

stator is made up of several windings connected in series to form a single circuit

Answer 10

Single-phase alternator

Question 11

has two or more single phase windings; windings are electrically separated from each other so that one would cut the maximum number of flux lines, and the other one would not cut any

Answer 11

Two-phase alternator

Question 12

referred to as ‘polyphase alternator’

Answer 12

Three-phase alternator

Question 13

it has three single-phase windings spaced so that the voltage induced in each windings is ____ out of phase with the voltage in the other two windings

Answer 13

Three-phase alternator, 120 degrees

Question 14

most powerplant utilize this concept for it allows an increase in power

Answer 14

operating in parallel (paralleling generators)

Question 15

To parallel two generators, their terminal voltages must be _____, and voltages must be _______, as well as their frequencies must be equal.

Answer 15

equal, in phase

Question 16

when conditions in parallel generators are met, they are now operating in ______

Answer 16

synchronism

Question 17

the process of getting the generators into synchronism is called

Answer 17

synchronizing

Question 18

consists of a frame (yoke) and two end brackets (bearings housing)

Answer 18

enclosure

Question 19

holds the components together and protects it

Answer 19

enclosure

Question 20

permits the cooling air to flow through the motor

Answer 20

open enclosure

Question 21

limits the flow of air into the motor

Answer 21

totally enclosed enclosure

Question 22

Types of Totally Enclosed Enclosure

Answer 22

totally enclosed non-ventilated enclosure, totally enclosed fan-cooled enclosure, explosion-proof enclosure

Question 23

2 Main Parts of Stator

Answer 23

stator core, stator windings

Question 24

an electromagnet when built and current is applied

Answer 24

stator

Question 25

made up of many thin metal sheets known as laminations

Answer 25

stator core

Question 26

thin metal sheets making up the stator core

Answer 26

laminations

Question 27

used to reduce energy losses

Answer 27

stator core

Question 28

directly connected in the power source

Answer 28

stator windings

Question 29

rotating part of the electromagnetic circuit

Answer 29

rotor

Question 30

mounted on the shaft and support the rotor to turn

Answer 30

bearings

Question 31

metal box on motor which protects one or more terminal boards

Answer 31

conduit box

Question 32

Two Types of Commutator Motor

Answer 32

AC Series Motor, Repulsion Motor

Question 33

known as the universal motor

Answer 33

AC series motor

Question 34

repulsion motor has an armature and commutator similar to that of a dc motor; brushes are not connected to the supply but are short-circuited

Answer 34

repulsion motor

Question 35

not self-starting; magnetic field set up in the stator by the ac power supply stays lined up in one direction

Answer 35

induction motor

Question 36

if two stator windings of unequal impedance are spaced 90 degrees apart but connected in parallel to a single-phase source, the filed produced will appear to rotate

Answer 36

Split-Phase Motor

Question 37

Two Types of Split-Phase Motor

Answer 37

Capacitor Start Motor, Permanent Capacitor Motor

Question 38

windings connected to a commutator

Answer 38

repulsion start induction motor

Question 39

a shaded pole is produced by a short-circuited coil wound around a part of each pole of a motor

Answer 39

shaded-pole motor

Question 40

several types exist to drive electric clocks, phonograph, turntables, and other devices requiring precise rotation

Answer 40

synchronous motor

Question 41

most used type of AC motor because of its simple, rugged construction, and good operating characteristics

Answer 41

induction motors

Question 42

laminated core with conductors placed parallel to the shaft

Answer 42

squirrel cage motor

Question 43

insulated winding similar to the stator winding

Answer 43

wound rotor motor

Question 44

rotor circuit is excited and have stators that produced rotating magnetic fields

Answer 44

synchronous motors