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WorksheetsELECTRICAL ENGINEERS PRE-BOARD EXAMINATION AUGUST 2018
Total questions: 44
Worksheet time: 22mins
This is the compact arrangement of switching devices.
Circuit protector
Switchboard
Switchgear
Panelboard
With reference to armature windings, wave windings, wave windings are often called_______ windings
Cascade
Series
parallel
ring
In case of delta connected circuit, when one resistor is open, power will be
unaltered
reduced to 1/9
reduced to 1/16
reduced by 1/3
Residual magnetism is necessary in a
separately excited generator
self-excited generator
both of these
none of these
Inside a hollow spherical conductor
electric field is zero
electric field is constant
electric field changes with distance from the center of the sphere
electric field is unity
The dummy coil in dc machines is used to
eliminate reactance voltage
eliminate armature reaction
bring about mechanical balance of armature
eliminate harmonics developed in the machine
In an ACB sequence balanced 3 phase system, the angle between the line voltage and the line current is 50°, what is the lagging power factor of the system?
0.30
0.50
0.64
0.94
An ideal full-wave rectifier with non-inductive load has zero transformation losses. What is the efficiency?
70%
80%
90%
100%
If the of a dc shunt motor is opened
it will continue to run at its rated speed
the speed of the motor will become very high
The motor will stop
the speed of the motor will decrease
The condition of a liquid electrolyte is measured in terms of its
current value
specific gravity
acid content
voltage output
Efficiency is secondary consideration in case of
base load plants
peak load plants
both base load and peak plants
none of these
Energy radiated continuously in the form of lighting waves is called?
luminous intensity
lumen
luminousflux
llumination
What is the equivalent IEEE device function number for directional power relay?
21
32
37
87
The rms value of pure cosine function is
0.5 of peak value
0.707 of peak value
same as peak value
zero
The effect of corona is
increased reactance
increased inductance
Increased energy loss
all of these
One of the advantages of distributing the winding in alternators is to
reduce harmonics
reduce the amount of copper
improve voltage waveform
decrease the value of the voltage
At very low frequencies a series RC circuit behaves as almost purely
resistive
inductive
capacitive
none of these
In a loss-free RLC circuit, the transient current is
oscillating
Square wave
sinusoidal
non-oscillating
Alternators installed in a hydro power station, are of
low speed
high speed
medium speed
very high speed
PDC in EPIRA means
Philippine Distribution Commission
Philippine Distribution Code
Philippine Distribution Corporation
Philippine Distribution Company
In a synchronous motor, the magnitude of stator back emf depends on
load on the motor
dc excitation only
both the speed and rotor flux
none of theses
Which of the following power plant is a conventional source of energy?
Solar energy
Geothermal energy
Coal energy
Wind energy
Open circuit test on transformer is conducted to determine
hysteresis loss
copper loss
core loss
eddy current loss
For two alternators operating in parallel, if the load shared by one of the, to be increased, as field excitation is
to be strengthened keeping input torque the same
to be weakened keeping input torque the same
to be kept constant but input torque should be increased
to be kept constant but input torque should be decreased
What does PEMC in EPIRA stands for
Philippine Energy Market Corporation
Private Energy Marketing Company
Philippine Energy Market Corporation
Philippine Electrical Marketing Corporation
The current flowing in L and C at parallel resonance are
zero
equal
infinite
Difference
When installing two grounding electrodes, the minimum distance between them is
1,800 mm
2,000 mm
1,500 mm
2,400 mm
Which of the following methods of generating electric power from the sea water is more advantageous?
water power
ocean power
tidal power
none of these
In television system, channels 2 and 13 are classified as
VHF
UHF
SHF
EHF
A two terminal pair of network of a transmission line can be represented by a
Л- network
T-network
either (A) or (B)
tree network
Surge impedance of transmission line is given by
√C/L
√LC
1/√LC
√L/C
The effective resistance of conductor is increased by
skin effect
proximity effect
corona effect
(a) and (b)
If the effect of earth is taken into account, then the capacitance of line to ground
decreases
increases
remains unchanged
becomes infinite
Peak load plants are designed to supply power at
low capital cost and low operating cost
high capital cost and low operating cost
low capital cost and high operating cost
high capital cost and high operating cost
Base load plants are designed to supply power at
low capital cost and low operating cost
high capital cost and low operating cost
low capital cost and high operating cost
high capital cost and high operating cost
Which of the following shall be included in the calculation of the reliability standard indices of the distributor asset by the Philippine Distributor Code?
Outages that occur on the secondary lines of the distribution system
Planned outages where the customers have been notified at least three(3) days prior to the loss of power
Outages that occur on the primary lines of the distribution system
Outages that occur in the transmission line
The condition in Ohm’s Law is that
ratio V/I should be constant
current should be proportional to voltage
the temperature should remain constant
the temperature should vary
If the torque angle continuously increases, system will become
stable
unstable
oscillatory stable
asymptotic stable
Which of the following insulators will be selected for high voltage application?
strain type
disc type
suspension type
pin type
What is the maximum number of bands permitted in rigid conduits between outlets?
4 quarter bends
6 quarter bends
2 quarter bends
quarter bends
The overcurrent protective device is caused to operate by
voltage surge
current flow
voltage drop
impedance
In the transformers
high tension winding is used near the core
high tension winding is used away from the core
low tension winding is used near the core
low tension winding is used away from the core
Which of the following parameters can be neglected for a short line?
resistance
inductance
reactance
capacitance
The curve representing Ohm’s law is
a parabola
linear
a sine function
a hyperbola
