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  • Almeda, Abegail S.

  • 問題数 99 • 3/18/2024

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    問題一覧

  • 1

    Turbo alternators usually have

    2 Poles

  • 2

    The protection from negative sequence currents is provided for

    generators

  • 3

    the value of diversity factor is

    greater than one

  • 4

    The turbine used for high head in hydro plant is

    Pelton turbine

  • 5

    The per unit impedances of a transformer referred from the primary and secondary side

    A. are equal

  • 6

    For load flow analysis transmission line are represented

    nominal pi

  • 7

    The bus bar of the power system, whose voltage magnitude and angle is not known. is called

    load bus

  • 8

    The zero sequence current in delta winding of Wye/Delta transformer is found

    if neutral point of Y winding is earthed

  • 9

    The zero sequence current will not flow in the

    L - L fault

  • 10

    One conductor open in a three phase transmission line will develop

    a parallel connection of sequence networks,

  • 11

    The steady state stability limit of a two-machine system depends on

    per unit reactance of the power system

  • 12

    a shunt fault is characterized by

    increase in current reduction, frequency and pf

  • 13

    Most economic load on an overhead line is

    greater than the natural load

  • 14

    The most economical load on an underground cable is

    less than the surge loading

  • 15

    Capacitors with it as easily done with

    C. Vacuum circuit breaker

  • 16

    In subsequent iteration, a voltage the controlled bus is treated as load bus when it's

    Reactive power limit is violated

  • 17

    The voltage magnitude of a particular bus can be controlled by controlling the

    B. Reactive power of the bus

  • 18

    Convergeance of the transmission load flow is always assured in case of

    both A and C

  • 19

    For the stable operation of interconnected system, the passive element that can be used as interconnecting elements is.

    reactor

  • 20

    The positive sequence component of the voltage at the point of fault is zero when it is a

    three phase fault

  • 21

    Load flow study is carried out for

    system planning

  • 22

    The main consideration for higher operating voltage of transmission is to

    C. increase power transfer capability

  • 23

    If the effect of earth is taken into account, then the capacitance of line to ground

    Increases

  • 24

    For a wye - delta transformer Y-side grounded, the zero sequence current

    exist in the line on the Y-side

  • 25

    If real power demand is suddenly increased, frequency of the system will

    decreases

  • 26

    taps of the transponder must be done at

    high voltage

  • 27

    Fuse in motor provides

    Short circuit protection

  • 28

    In grounding which is permitted as a grounding electrode I. Building metal frame II. Metal water pipe

    both I & II

  • 29

    Which is not standards circuit rating

    25 A

  • 30

    A circuit must be protected againts,

    Overload, short-circuit, or leakage, voltage spikes

  • 31

    The location of the disconnecting means from the second building I. Disconnecting means must be located outside the second building on accessible location II. Disconnecting means must be located inside the entrance of the second building

    Both I & II

  • 32

    What is the minimum clearance of service drop above the driveway

    3700 mm

  • 33

    Thermal protection it's mainly use as ___ protection

    Overload

  • 34

    What is the modern light sensor use in fax machine

    Charged coupled device

  • 35

    What is/are the fundamental process of resistance welding

    Heat and squeeze

  • 36

    In single phase, 3-wire system, the middle conductor must be which of the following

    Grounded wire

  • 37

    How many three-way and four-way switches for a lighting system control in five different location

    2-3 way & 3-4 way

  • 38

    ___ is also known as "Cold standby reserve"

    Back up reserve

  • 39

    Which of the following is included in the calculation reliability indices of distribution code?

    34.5 kV line outages

  • 40

    What is the maximum voltage in dwelling unit

    230 V

  • 41

    What is the minimum diameter of the ground rod

    16 mm

  • 42

    What is the minimum size of underground service lateral conductor

    8.0 mm² copper

  • 43

    Play electrode shall be installed of not less than ___ mm below the surface of the soil

    750 mm

  • 44

    In the Philippine electrical code, the branch circuit permissible load is __ %

    80

  • 45

    The main purpose bonding jumper is to connect equipment grounding conductors and ___ to the grounded conductor of the system

    Service disconnect enclosure

  • 46

    In an alternating current circuit, the voltage lags the current. What element should be placed in parallel to the circuit to improve the power factor unity

    Inductor

  • 47

    Which of the following is not considered exterior wall space in dwelling?

    Sliding panel

  • 48

    What is the purpose of earthing

    Prevent electric shock

  • 49

    A gas turbine power plant usually suits for

    Peak load operation

  • 50

    Which of the following plant is expected to have the longer expected life

    Steam

  • 51

    The purpose of the grid system is to

    Interconnect the Power Station

  • 52

    One of the line parameters which is neglected in short transmission line is

    Capacitance

  • 53

    The economical section of feeder can be obtained by applying

    Kelvin's Law

  • 54

    Energy radiated continuously in the form of lighting waves is called

    Luminous flux

  • 55

    The luminous intensity of a lamp is expressed in

    Candela

  • 56

    The relative permeability of paramagnetic substance

    Slightly greater than one

  • 57

    Which of the following has the highest value of relative permeability

    Supermalloy

  • 58

    The torque of a synchronous motor when reach synchronism is called

    Pull in torque

  • 59

    Month of March is the fire prevention, what is the electrical safety month

    April

  • 60

    What angle will be illumination be halved to the object

    60

  • 61

    Minimum thickness of concrete in a concrete in case electrode is

    50 mm

  • 62

    The phenomenon of rise in voltage at the receiving end of the open circuited or lightly loaded line is called

    Ferranti effect

  • 63

    what is the IEEE STANDARD DEVICE NUMBER FOR INSTANTANEOUS OVER CURRENT RELAY

    50

  • 64

    Induction motor is running at rated load. what will happen when one winding of a delta connected motor is suddenly cut

    will burn

  • 65

    Energy stored in an inductor is given by

    1/2 LI^2 Joules

  • 66

    Which of the following is vector quantity

    Magnetic field density

  • 67

    The two conductors of transmission line carry equal currrent (I) in opposite direction. the force on each conductor is

    Proportional to I^2

  • 68

    The ratio of intensity of magnetization to the magnetization force is known as

    Susceptibility

  • 69

    Paramagnetic materials have relative permeability

    Slightly greater than one

  • 70

    The unit of magnetic flux is

    Weber

  • 71

    Permeability in a magnetic circuit corresponds to an electric circuit

    Conductivity

  • 72

    What is the standard device number for overvoltage relay

    59

  • 73

    What is the standard device number for directional power relay

    32

  • 74

    The unit of capacitance is

    coulombs/volts

  • 75

    "The total electric flux through any closed surface surrounding charges is equal to the amount of charge enclosed". The above statement is associated with

    gauss's law

  • 76

    Voltage across capacitor at any time t during charging from a DC source of voltage V is given by

    v = V (1 - e^-t/λ)

  • 77

    The breakdown voltage for paper capacitors is usually.

    200 to 1600 volts

  • 78

    The property of a material which opposes the creation of magnetic flux in it is known as

    reluctance

  • 79

    The coefficient of self-inductance for a coil is given as

    Nφ/I

  • 80

    "The mass of an ion liberated at an electrode is directly proportional to the quantity of electricity". The above statement is associated with

    faraday's law of electrolysis

  • 81

    The power consumed in a circuit element will be least when the phase difference between the current and voltage is

    90 degree

  • 82

    The commutator segments are connected to the armature conductors by means of

    copper lugs

  • 83

    For a DC generator when the number of poles and the number of armature conductors is fixed, then which winding will give the higher emf?

    B. wave winding

  • 84

    Iron losses in DC machine are independent variation in

    load

  • 85

    Brushes of DC Machines are made of

    carbon

  • 86

    No-load speed of which of the following motor will be highest?

    series motor

  • 87

    If a DC motor is to be selected for conveyors, which motor would be preferred

    Series motor

  • 88

    Small DC motors up to 5 HP usually have

    2 poles

  • 89

    The mechanical power developed by shunt motor will be maximum when the ratio of back EMF applied voltage is

    0.5

  • 90

    The no-load current drawn by transformer is usually what percent of the full load current

    2 to 5 percent

  • 91

    Dielectric strength of transformer oil is expected to

    33kV

  • 92

    The maximum efficiency of a distribution transformer is

    at 50% full load

  • 93

    The frequency of the voltage generated in large alternators

    50 Hz

  • 94

    Harmonic component of generated EMF will be more in

    Full pitch coil

  • 95

    The dark and bright lamp method is used for

    Synchronizing

  • 96

    An alternator driven by a Francis hydraulic turbine is a ….... alternator?

    low or medium speed

  • 97

    For low head and high discharge, the hydraulic turbine used is

    Kaplan turbine

  • 98

    Which device is used to chane the kW output of generators in parallel?

    Governor

  • 99

    Which motor is used in food mixer

    universal motors