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Elementary Electrical Engineering (AC/DC) > DC Machines > Flashcards

DC Machines Flashcards

1
Q

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

A

electromagnetic conduction

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2
Q

supplies the needed electrical energy

A

generators

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3
Q

2 Types of Generator

A

DC Generator, AC Generator

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4
Q

DC generator is also known as

A

Dynamo

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5
Q

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

A

DC generator

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6
Q

What is the current flow of a DC generator?

A

unidirectional

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7
Q

AC generator is also known as

A

alternators

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8
Q

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

A

AC generator

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9
Q

What is the current flow of an AC generator?

A

reverse

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10
Q

Who demonstrated that a magnetic field could create current flow?

A

English scientist Michael Faraday

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11
Q

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 ______

A

galvanometer

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12
Q

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

A

zero

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13
Q

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

A

deflects from the zero position

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14
Q

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

A

DC generator

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15
Q

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

A

voltage

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16
Q

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

A

complete

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17
Q

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

A

commutator

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18
Q

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

A

yoke or field frame

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19
Q

carries the magnetic flux produced by the field winding

A

yoke or field frame

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20
Q

the magnetizing force inside a generator

A

pole/pole shoe/field pole

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21
Q

the core of the electromagnet

A

pole/pole shoe/field pole

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22
Q

support field coils and spread out the flux in air gap

A

pole/pole shoe/field pole

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23
Q

wire of the electromagnet; goes together with the pole

A

field winding or field coil

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24
Q

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

A

field winding or field coil

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25
Q

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

A

armature assembly

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26
Q

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

A

armature core

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27
Q

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

A

armature coil or armature winding

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28
Q

Two Methods of Wounding of Armature Coil/Winding

A

Lap Winding, Wave Winding

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29
Q

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

A

Lap Winding

30
Q

a method for stabilizing the armature magnetic field

A

Lap Winding

31
Q

Types of Lap Winding

A

Simplex, Duplex, Triplex

32
Q

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

A

simplex

33
Q

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

A

duplex

34
Q

in effect three separate sets of series-connected coils

A

triplex

35
Q

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

A

wave winding

36
Q

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

A

commutator

37
Q

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

A

brushes

38
Q

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

A

pig tail

39
Q

generator field’s coils are energized from an external source

A

separately excited

40
Q

the generator supplies its own excitation

A

self-excited

41
Q

where the field winding is in series with armature winding

A

series wound

42
Q

where the field winding is in parallel with armature winding

A

shunt-wound

43
Q

combination of series and shunt winding; usually used more often

A

compound-wound

44
Q

when the shunt field is parallel only with the armature

A

short-shunt

45
Q

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

A

long-shunt

46
Q

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

A

stator

46
Q

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

A

DC motor

46
Q

used to carry armature winding; cylindrical in shape

A

rotor

46
Q

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

A

armature winding

47
Q
A
48
Q

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

A

armature winding

49
Q

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

A

field winding

50
Q

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

A

commutator

51
Q

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

A

brushes

52
Q

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

A

poles

53
Q

a magnetic material used for mechanical support and protection

A

slot or teeth

54
Q

supports the iron core, brushes, and the bearings

A

motor housing

55
Q

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

A

torque

56
Q

Types of Torque

A

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

57
Q

necessary to produce its rated horsepower at full-load speed

A

full-load torque

58
Q

aids to bring motor up to rated speed

A

pull-up torque

59
Q

maximum torque the motor will develop

A

breakdown torque

60
Q

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

A

locked-rotor torque

61
Q

most common type of torque

A

locked-rotor torque

62
Q

Motor Types

A

Shunt Motor, Series Motor, Compound Motor

63
Q

most common type of DC motor

A

shunt motor

64
Q

connected in the same way as shunt generator

A

shunt motor

65
Q

most ideal for practical uses

A

shunt motor

66
Q

one of the traditional ‘work-horses’ or electromechanical energy transition

A

series motor

67
Q

combines the operating characteristics of the shunt and series motors

A

compound motor

68
Q

motor may be operated safely at no load

A

compound motor

69
Q

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

A

compound motor

Elementary Electrical Engineering (AC/DC) (9 decks)

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