DC Machines

Question 1

generators are electrical components that convert mechanical energy to electrical energy through

Answer 1

electromagnetic conduction

Question 2

supplies the needed electrical energy

Answer 2

generators

Question 3

2 Types of Generator

Answer 3

DC Generator, AC Generator

Question 4

DC generator is also known as

Answer 4

Dynamo

Question 5

a generator that converts the alternating current to a direct current using a commutator

Answer 5

DC generator

Question 6

What is the current flow of a DC generator?

Answer 6

unidirectional

Question 7

AC generator is also known as

Answer 7

alternators

Question 8

a generator that converts mechanical energy to electrical energy in the form of alternating current

Answer 8

AC generator

Question 9

What is the current flow of an AC generator?

Answer 9

reverse

Question 10

Who demonstrated that a magnetic field could create current flow?

Answer 10

English scientist Michael Faraday

Question 11

magnetic field creating current flow is demonstrated by several turns of wire wrapped around a cardboard tube, and the ends of the conductor are connected to a ______

Answer 11

galvanometer

Question 12

When a magnet is at rest inside the tube, the galvanometer shows a reading of ____

Answer 12

zero

Question 13

When the bar magnet is moved through the tube, the galvanometer ______

Answer 13

deflects from the zero position

Question 14

can be created by an armature coil with a single turn of wire

Answer 14

DC generator

Question 15

When the armature coil cuts across the magnetic field, it produces _____

Answer 15

voltage

Question 16

When a _______ path is present, current will move through the circuit.

Answer 16

complete

Question 17

allows both brushes to have contact with the portion of the loop that moves upward and downward

Answer 17

commutator

Question 18

outer frame of a DC generator; made up of cast iron/steel

Answer 18

yoke or field frame

Question 19

carries the magnetic flux produced by the field winding

Answer 19

yoke or field frame

Question 20

the magnetizing force inside a generator

Answer 20

pole/pole shoe/field pole

Question 21

the core of the electromagnet

Answer 21

pole/pole shoe/field pole

Question 22

support field coils and spread out the flux in air gap

Answer 22

pole/pole shoe/field pole

Question 23

wire of the electromagnet; goes together with the pole

Answer 23

field winding or field coil

Question 24

composed of many turns of wire; produces the flux cut by the armature

Answer 24

field winding or field coil

Question 25

consists of the armature core, armature coils/armature windings, commutator

Answer 25

armature assembly

Question 26

rotor of a generator, mounted on a shaft that rotates in bearings located in the generator's end frames; acts as a conductor when it is rotated

Answer 26

armature core

Question 27

former wound copper coil which rests in armature slots; can be wounded through 2 methods

Answer 27

armature coil or armature winding

Question 28

Two Methods of Wounding of Armature Coil/Winding

Answer 28

Lap Winding, Wave Winding

Question 29

one end of a single armature coil attaches to one commutator segment, while the other end is soldered to the adjacent segment

Answer 29

Lap Winding

Question 30

a method for stabilizing the armature magnetic field

Answer 30

Lap Winding

Question 31

Types of Lap Winding

Answer 31

Simplex, Duplex, Triplex

Question 32

ends of each coil are connected to adjacent commutator segments; all the coils are connected in series

Answer 32

simplex

Question 33

there are in effect two separate sets of coils, each set connected in series; two sets of coils are connected to each other, only by the brushes

Answer 33

duplex

Question 34

in effect three separate sets of series-connected coils

Answer 34

triplex

Question 35

ends of each coil are connected to commutator segments two pole spans apart

Answer 35

wave winding

Question 36

used to convert the alternating current flowing in its armature into the direct current at its terminals

Answer 36

commutator

Question 37

ride on the surface of the commutator and act as the electrical contact between armature coils and an external circuit

Answer 37

brushes

Question 38

a flexible braided-copper inductor which connects each brush to the external circuit

Answer 38

pig tail

Question 39

generator field's coils are energized from an external source

Answer 39

separately excited

Question 40

the generator supplies its own excitation

Answer 40

self-excited

Question 41

where the field winding is in series with armature winding

Answer 41

series wound

Question 42

where the field winding is in parallel with armature winding

Answer 42

shunt-wound

Question 43

combination of series and shunt winding; usually used more often

Answer 43

compound-wound

Question 44

when the shunt field is parallel only with the armature

Answer 44

short-shunt

Question 45

when the shunt field is in parallel with both the armature and series field

Answer 45

long-shunt

Question 46

used to carry the field winding and poles; hollow cylinder which works together with the rotor to constitute magnetic circuit

Answer 46

stator

Question 46

its function is to develop turning effort, or torque, to produce mechanical rotation

Answer 46

DC motor

Question 46

used to carry armature winding; cylindrical in shape

Answer 46

rotor

Question 46

load carrying member of the rotor; a continuous winding, without a beginning or an end

Answer 46

armature winding

Question 48

rotates in the magnetic field and is composed of numerous coils in series

Answer 48

armature winding

Question 49

an exciting system which may be an electrical winding or a permanent magnet; located on the stator

Answer 49

field winding

Question 50

rotates with the rotor and serves to rectify the induced voltage and the current in the armature, both of which area alternating current

Answer 50

commutator

Question 51

conducting carbon graphite spring loaded to ride in the commutator and act as interface between the external circuit and the armature winding

Answer 51

brushes

Question 52

provided to place field winding; number of poles is determined by the voltage and current ratings of the machine

Answer 52

poles

Question 53

a magnetic material used for mechanical support and protection

Answer 53

slot or teeth

Question 54

supports the iron core, brushes, and the bearings

Answer 54

motor housing

Question 55

starting twist or force that produces rotation in a motor; rotation necessary for starting a motor

Answer 55

torque

Question 56

Types of Torque

Answer 56

full-load torque, pull-up torque, breakdown torque, locked-rotor torque

Question 57

necessary to produce its rated horsepower at full-load speed

Answer 57

full-load torque

Question 58

aids to bring motor up to rated speed

Answer 58

pull-up torque

Question 59

maximum torque the motor will develop

Answer 59

breakdown torque

Question 60

develop when full power is applied when rotor is stationary; the starting twist to get the rotor running

Answer 60

locked-rotor torque

Question 61

most common type of torque

Answer 61

locked-rotor torque

Question 62

Motor Types

Answer 62

Shunt Motor, Series Motor, Compound Motor

Question 63

most common type of DC motor

Answer 63

shunt motor

Question 64

connected in the same way as shunt generator

Answer 64

shunt motor

Question 65

most ideal for practical uses

Answer 65

shunt motor

Question 66

one of the traditional 'work-horses' or electromechanical energy transition

Answer 66

series motor

Question 67

combines the operating characteristics of the shunt and series motors

Answer 67

compound motor

Question 68

motor may be operated safely at no load

Answer 68

compound motor

Question 69

as load is added, its speed decreases, and torque is greater compared with that of a shunt motor

Answer 69

compound motor