MES Departmental • 2026 • Engineering Paper-II
What is the most common cause of premature failure of pin insulators on 11kV lines?
A)
Accumulation of dust, salt, or industrial pollution causing leakage currents and flashovers
B)
Over-voltage in the system
C)
High ambient temperature in the summer
D)
High frequency AC transmission
Option A is correct: Accumulation of dust, salt, or industrial pollution causing leakage currents and flashovers.
MES Departmental • 2026 • Engineering Paper-II
Which instrument is primarily used to measure the insulation resistance of a transformer?
A)
Multimeter
B)
Megger
C)
Voltmeter
D)
Ammeter
Option B is correct: Megger.
MES Departmental • 2026 • Engineering Paper-II
Why are gas turbines frequently used in power grids for “peaking” applications?
A)
They have high capital costs but run efficiently at baseloads
B)
They take hours to synchronize with the power grid
C)
They have fast start-up times and can quickly meet peak electricity demands
D)
They do not require a compressor to operate
Option C is correct: They have fast start-up times and can quickly meet peak electricity demands.
MES Departmental • 2026 • Engineering Paper-II
What type of core transformer configuration is typically used in a grid distribution substation to provide a safe neutral wire for domestic consumer single-phase loads?
A)
Delta–Delta (-) connection.
B)
Star–Star (Y-Y) connection.
C)
Delta–Star (-Y) step-down connection.
D)
Open-Delta (V-V) connection
Option C is correct: Delta–Star (-Y) step-down connection..
MES Departmental • 2026 • Engineering Paper-II
From an economic and practical standpoint, what is the ideal location for a distribution substation?
A)
Far away from residential areas to avoid electromagnetic fields.
B)
Exactly at the geographical center of the city.
C)
At the load center.
D)
Right next to the primary generating station.
Option C is correct: At the load center..
MES Departmental • 2026 • Engineering Paper-II
How is the primary winding of a Potential Transformer (PT/CVT) connected to the line?
A)
In series with the load
B)
In parallel (across the phase and neutral or phase to phase)
C)
In delta connection only
D)
Through a current limiting resistor
Option B is correct: In parallel (across the phase and neutral or phase to phase).
MES Departmental • 2026 • Engineering Paper-II
How is a power transformer protected from indirect lightning strikes or induced overvoltages?
A)
By using overcurrent relays
B)
By using overhead ground wires (shield wires)
C)
By using Differential protection
D)
By using conservator tanks
Option B is correct: By using overhead ground wires (shield wires).
MES Departmental • 2026 • Engineering Paper-II
In terms of heat transfer, what is equivalent to “One Ton of Refrigeration”?
A)
The heat required to melt 1 ton of ice at 0°C in 24 hours
B)
The cooling required to freeze 1 ton of water into ice at 0°C in 24 hours
C)
The heat absorbed by the evaporator in one minute
D)
The rate of heat transferred in 1 hour
Option A is correct: The heat required to melt 1 ton of ice at 0°C in 24 hours.
MES Departmental • 2026 • Engineering Paper-II
The function of a conservator in a power transformer is to:
A)
protect against internal faults.
B)
cool the transformer oil.
C)
provide physical support to the core.
D)
take care of the expansion and contraction of transformer oil due to temperature variation.
Option D is correct: take care of the expansion and contraction of transformer oil due to temperature variation..
MES Departmental • 2026 • Engineering Paper-II
Which compressor control strategy involves stopping the motor when the target system pressure is reached, and restarting it when pressure drops?
A)
Variable Speed Drive (VSD) control
B)
Constant speed control with blow-off
C)
Start/Stop control
D)
Suction throttling
Option C is correct: Start/Stop control.
MES Departmental • 2026 • Engineering Paper-II
What is the fundamental principle of a Percentage Differential Relay used in transformers?
A)
Measures the voltage drop across the line.
B)
Compares currents entering and leaving the protected zone.
C)
Senses changes in ambient temperature.
D)
Operates based on the frequency of the system
Option B is correct: Compares currents entering and leaving the protected zone..
MES Departmental • 2026 • Engineering Paper-II
What type of speed variation does a flywheel control?
A)
Variation of speed over a long duration
B)
Intermittent fluctuations within a cycle (cyclic variations)
C)
Speed variations caused by sudden load changes
D)
Non-uniform load torque variations
Option B is correct: Intermittent fluctuations within a cycle (cyclic variations).
MES Departmental • 2026 • Engineering Paper-II
Which soil type consistently shows the lowest resistivity value, making it naturally ideal for electrical grounding?
A)
Dry sand
B)
Solid granite rock
C)
Clay or moist loamy soil
D)
Gravel beds
Option C is correct: Clay or moist loamy soil.
MES Departmental • 2026 • Engineering Paper-II
Why is a Magnetic Balance Test conducted on a three-phase transformer during pre-commissioning?
A)
To calculate the total copper losses at full load
B)
To check for inter-turn shorts, core unbalance, or physical displacement of the windings
C)
To evaluate the speed of the cooling fan motors
D)
To measure the insulation resistance of the neutral bushing
Option B is correct: To check for inter-turn shorts, core unbalance, or physical displacement of the windings.
MES Departmental • 2026 • Engineering Paper-II
When looking to purchase a domestic refrigerator for home use, how is the capacity typically measured?
A)
Kilowatts per day
B)
Cubic feet (CFT) or Liters
C)
Horsepower
D)
British Thermal Units (BTU)
Option B is correct: Cubic feet (CFT) or Liters.
MES Departmental • 2026 • Engineering Paper-II
What critical maintenance activity prevents “contact welding” or local hotspots in outdoor isolator blades?
A)
Painting the contact surfaces with anti-corrosive zinc paint.
B)
Applying a thin layer of conductive, oxidation-inhibiting petroleum jelly or grease to the contacts.
C)
Increasing the spring tension until the blade cannot be moved manually.
D)
Washing the contacts thoroughly with high-pressure water while energized.
Option B is correct: Applying a thin layer of conductive, oxidation-inhibiting petroleum jelly or grease to the contacts..
MES Departmental • 2026 • Engineering Paper-II
What is the standard assumed indoor condition for human comfort when sufficient data is not available?
A)
40°C DBT and 75% RH
B)
25°C DBT and 80% RH
C)
21°C DBT and 50% RH
D)
30°C DBT and 70% RH
Option C is correct: 21°C DBT and 50% RH.
MES Departmental • 2026 • Engineering Paper-II
What is a major financial benefit of applying work study techniques in an organization?
A)
It increases overhead expenditures.
B)
It minimizes product costs by eliminating waste and inefficiencies.
C)
It leads to an immediate increase in raw material consumption.
D)
It eliminates the need to pay employee bonuses
Option B is correct: It minimizes product costs by eliminating waste and inefficiencies..
MES Departmental • 2026 • Engineering Paper-II
If the load on the engine increases, how does the governor respond?
A)
It increases the speed of the flywheel
B)
It stores more kinetic energy
C)
It increases the supply of the working fluid (fuel)
D)
It decreases the supply of the working fluid (fuel)
Option C is correct: It increases the supply of the working fluid (fuel).
MES Departmental • 2026 • Engineering Paper-II
Why are fins generally made as thin as possible for heat transfer?
A)
To reduce the total weight
B)
To accommodate a larger number of fins in a given space
C)
To increase the width of the profile
D)
To increase structural strength
Option B is correct: To accommodate a larger number of fins in a given space.
MES Departmental • 2026 • Engineering Paper-II
Before energizing a power transformer for the first time during commissioning, what does a “BDV test” evaluate?
A)
Bulk Density Verification of the transformer core steel
B)
Breakdown Voltage of the transformer insulating oil
C)
Balanced Direct Voltage of the control batteries
D)
Bushing Displacement Vector alignment
Option B is correct: Breakdown Voltage of the transformer insulating oil.
MES Departmental • 2026 • Engineering Paper-II
If you increase the distance ‘a’ between the four test pins in a Wenner test setup, what practical change occurs?
A)
You measure soil resistivity at a deeper layer of the earth.
B)
The measured test voltage increases dramatically.
C)
You measure only the dry top soil layer.
D)
The meter automatically runs out of scale range.
Option A is correct: You measure soil resistivity at a deeper layer of the earth..
MES Departmental • 2026 • Engineering Paper-II
Which type of fin profile in heat transfer system yields the maximum heat flow per unit weight?
A)
Straight rectangular fin
B)
Straight triangular fin
C)
Parabolic fin
D)
Pin fin
Option B is correct: Straight triangular fin.
MES Departmental • 2026 • Engineering Paper-II
Why is AC used instead of DC for measuring ground soil resistivity and earth resistance?
A)
AC travels faster in soil
B)
AC prevents soil electrolytic polarization and stray DC bias interference
C)
DC voltage cannot sink into deep earth
D)
AC instruments consume less battery power
Option B is correct: AC prevents soil electrolytic polarization and stray DC bias interference.
MES Departmental • 2026 • Engineering Paper-II
What is the standard minimum ground clearance required for Low Tension (LT) and medium voltage lines crossing a street?
A)
4.5 meters
B)
5.8 meters
C)
6.1 meters
D)
7.2 meters
Option B is correct: 5.8 meters.
