FINALS QUESTIONNAIRES

Question 1

What part of DC Generator acts as a rectifier?

Answer 1

Commutator

Question 2

Is a rotating machine that supplies an electrical output with unidirectional voltage and current?

Answer 2

DC Generator

Question 3

Losses which occur because of friction between the parts of the generator.

Answer 3

Mechanical Losses

Question 4

These are the generators whose field magnets are energized by some external DC Source, such as a battery.

Answer 4

Separately Excited DC Generator

Question 5

A form of two-layer winding for electric machines in which each coils is connected in series with one adjacent to it.

Answer 5

Lap Winding

Question 6

Its main function is to supply magnetic fields around which the coil spin.

Answer 6

Stator

Question 7

The field winding of this generator is connected in parallel with the generator armature.

Answer 7

Shunt Wound Generators

Question 8

Is a mechanical piece in a DC machine that produces the rotational of a force known as torque and brings about rotation.

Answer 8

Shaft

Question 9

It is made up of soft iron laminations which are insulated from each other and tightly clamped
together

Answer 9

Armature Core

Question 10

These generators are generators whose field magnets are energized by the current supplied by themselves

Answer 10

Self Excited DC Generator

Question 11

His armature consists of an iron ring with projecting teeth interspeed with coils which formed a closed series circuit with connections to a commutator.

Answer 11

Antonio Pacinotti

Question 12

The.__________, component must be properly adjusted to what is called “neutral” position

Answer 12

Yoke

Question 13

For a cumulatively compound motor, torque at starting is greater than a ________?

Answer 13

Shunt Motor

Question 14

It has linear relationship existing between the field current and the amount of torque produced.

Answer 14

Series Wound Motors

Question 15

It is used to create mechanical revolutions and includes all the rotating electrical parts.

Answer 15

Rotor

Question 16

This type of DC motor has good regulation and it is also classified as a constant speed motor even though its speed does decreases slightly with an increase in load.

Answer 16

Shunt Motor

Question 17

Which type of DC motor has the same speed control techniques available as those available for a shunt motor? (scroll down for choices)

A. Cumulatively compounded DC motor

B. Differentially compounded DC motor

C. Both A and B but since B is almost never used, that fact hardly matters.

D. Neither A and B because each type of DC motor has a unique formulation.

Answer 17

C. Both A and B but since B is almost never used, that fact hardly matters.

Question 18

Type of self excited de motor in which the field windings are exposed to the entire terminal voltage as they are connected in parallel to the armature winding.

Answer 18

Shunt Wound DC Motor

Question 19

This type of permanent magnets are susceptible to high temperatures and become demagnetised. It can last over a 10 year period the loss in magnetic power would be un-noticeable.

Answer 19

Rare-earth Magnets

Question 20

Using Fleming’s Left Hand Rule, we can determine three parameters which are:

A. Magnetic Force
B. Direction of Current
C. Magnetic Field
D. All of the above

Answer 20

D. All of the above

Question 21

A transformer cannot be connected to the _______ because it will produce a steady current.

Answer 21

DC Supply

Question 22

Simply the generation of an induced EMF in a coil as a result of current flowing in an adjacent coil.

Answer 22

Electromagnetism

Question 23

At which category (Type) of transformer does a Distribution Transformer fall into

Answer 23

Step Down Transformer

Question 24

_____________ type of transformer which operates on single-phase power.

Answer 24

Single Phase Transformer

Question 25

Transformer's work on which principle/law?

Answer 25

Faraday's law of mutual induction

Question 26

In calculating efficiency transformer what is the value of Pc?

Answer 26

I1^2R1+I2^2Ro2

Question 27

What is the formula to get transformers EMF?

Answer 27

EMF=4.44FNØm

Question 28

Use of __________ transformer system (a series system) in the first large exposition of AC power in Turin, Italy.

Answer 28

Lucien Gaulard’s

Question 29

Lucien Gaulard and John Dixon Gibbs first built a _______ or in today's terminology a step down transformer which they designed with open iron core, the invention was not very efficient to produce.

Answer 29

Secondary Generator

Question 30

________________ type of transformers that are used to change voltage of electrical systems with three-phase.

Answer 30

Three Phase Transformer

Question 31

"Father of three-phase current"

Answer 31

Galileo Ferraris

Question 32

They had worked on motor, but it had a commutator.

Answer 32

Stanley and Thomson

Question 33

An important year for AC power.

Answer 33

1886

Question 34

In 1886 designs an improved version of the Siemens single phase alternator

Answer 34

William Stanley

Question 35

When did Charles Proteus Steinmetz publishes introduces new mathematic solutions to solve puzzles of the behavior of AC power with his article: "Note on the Law of Hysteresis" in Electrical Engineer issue number 137.

Answer 35

December 17, 1890

Question 36

is a kind of electric generator used in contemporary cars to run the electrical system while the engine is running and to charge the battery.

Answer 36

Automotive Alternators

Question 37

These generators are taken two at a time and run sequentially with a 120 degrees offset between them.

Answer 37

Three-Phase AC Generator

Question 38

The function of an ________________________ is to provide a steady stream of electrical energy to power all electrical devices and components within a machine

Answer 38

Alternator

Question 39

is used to convert current from alternating current (AC) to direct current (DC) during the charging process.

Answer 39

Rectifier

Question 40

is a machine that converts the MECHANICAL ENERGY into AC ELECTRICAL POWER.

Answer 40

AC Generator

Question 41

The stator is the stationary part of the motor’s electromagnetic circuit and is made up of thin metal sheets, called laminations.

Answer 41

Stator Core

Question 42

is a 1-phase motor that includes a stator as well as a rotor with a single cage.

Answer 42

Capacitor Start Induction Motor

Question 43

As the rotor coils are short-circuited, according to _______________, the current will start flowing through the coil of the rotor.

Answer 43

Faraday’s law of electromagnetic induction

Question 44

Coils of insulated wire are inserted into slots of the stator core

Answer 44

Stator Winding

Question 45

is a part of the motor used for the protection of the motor from the environment and persons from being touch.

Answer 45

Enclosure

Question 46

An alternate name of ____________ is a Resistance Start Motor

Answer 46

Split-Phase Induction Motor

Question 47

Conceives the idea of the first polyphase AC motor.

Answer 47

Galileo Ferraris

Question 48

Builds his first transformer and motor to work with his 3 phase AC system.

Answer 48

Dobrovolsky

Question 49

A _________________ gets produced in the stator due to the flow of current in the coil..

Answer 49

Magnetic Flux

Question 50

It is mounted on the shaft, support the rotor and allow it to turn.

Answer 50

Bearings

Question 51

Synchronous motors are generally not self-starting because…

Answer 51

…the direction of instantaneous torque reverses after half cycle

Question 52

A synchronous motor can develop synchronous torque…

Answer 52

…only at synchronous speed

Question 53

Synchronous motor always run at…

Answer 53

…the synchronous speed.

Question 54

Synchronous motor are... A. not- self starting B. Self-starting C. Essentially self-starting D. None of the above

Answer 54

A. not- self starting

Question 55

In a synchronous motor, which loss varies with load?

Answer 55

Copper loss

Question 56

the rotor copper losses, in a synchronous motor, are met by…

Answer 56

…DC Source.

Question 57

In which of the following motors the stator and the rotor magnetic field rotate at the same speed? A. Universal Motor B. Synchronous motor C. reluctance motor D. Induction motor

Answer 57

B. Synchronous motor

Question 58

Is the rotor loss being relatively smaller than stator loss due to the small DC rotor current flowing through the field winding?

Answer 58

Rotor Loss

Question 59

Is made of silicon steel material. It provides an easy path for the magnetic lines of force and accommodates the stator winding

Answer 59

Stator Core

Question 60

It is a type of losses that occur in the core or the iron parts of the synchronous motor due to the magnetic property of the material.

Answer 60

Iron and Core Losses