Download 1)______ types of Induction Motor are widely used. A. SlipringIM B

1)_____________ types of Induction Motor are widely used.
A. SlipringIM
B. Squirrel Cage IM
C. Single Phase IM
D. Three Phase IM
2) A 3φ, 12 pole, 600 V, 50 Hz star connected IM has rotor resistance and stand
still resistance of 0.03Ω and 0.5 Ω respectively. The speed of maximum
torque will be
A. 470 r.p.m
B. 450 r.p.m
C. 240 r.p.m
D. 540 r.p.m
3) Star-delta method of starting of motor is not possible in case of
A. High speed motor
B. Low horse power motor
C. Single phase Induction motor
D. High torque motor
4) In case of IM the torque is
A. inversely proportional to √slip
B. directly proportional to slip
C. directly proportional to slip2
D. inversely proportional to slip
5) In case of 3-phase IM, plugging means
A. Pulling the motor directly on line without a rotor
B. Locking of rotor due to harmonics
C. Interchanging two supply phases for quick stopping
D. Starting the motor on load which is more than the rated load
6)In a star-delta starting of an IM.
A. reduced voltage is applied to the stator
B. applied voltage per stator phase is 57.7% of a line voltage
C. line voltage is 57.7% of stator voltage
D. resistance is inserted in the rotor
7) Which of the following is not determined by circle diagram
A. Power factor
B. frequency
C. Efficiency
D. Output
8) An IM rotor input is 4500 watts and rotor cu loss is 300 watts, find slip.
A. 6.67%
B. 15%
C. 7.77%
D. Can’t be determined
9) For a 3φ transmission line transmission efficiency of a line decreases with
A. increase in load p.f.
B. Does not vary with power factor
C. increase in load current.
D. decrease in load p.f.
10) Which combination is true for any transmission line
A. A⃗ = 52, B⃗ = 0.8, C⃗ = 25, D⃗ = 0.385
B. . A⃗ = 42, B⃗ = 2.1, C⃗ = 29, D⃗ = 0.5
C. A⃗ = 45, B⃗ = 3.2, C⃗ = 28, D⃗ = 0.83
D. A⃗ = 22.69, B⃗ = 0.7, C⃗ = 32, D⃗ = 0.68
11) If in a short transmission line, resistance and reactance are found to be equal
and regulation appears to be zero, then the load will be
A. 0.707 leading
B. 0.707 lagging
C. have unity power factor
D. have zero power factor
12) When a neutral point of 3 φ system is directly connected to earth then it has
what type of grounding
A. solid
B. resistance
C. reactance
D. Peterson coil
13) Percentage of carbon is highest in
A. anthracite coal
B. bituminous coal.
C. lignite .
D. coal gas.
14) The 1st nuclear plant in world was commissioned in
A. U.S.S.R
B. U.S.A
C. UAE
D. ENGLAND
15) The concept of an electrically short, medium and long line is primarily based
on
A. nominal voltage of the line
B. physical length of the line
C wavelength of the line
D. power transmitted over the line
16) Keeping in view the cost and overall effectiveness, the following circuit
breaker is suited for capacitor bank switching
A. vacuum
B. oil
C. air blast
D. SF6
17) In a biased differential relay the bias is defined as the ratio of
A. fault current and operating coil current
B. operating coil current and restraining coil current
C. number of turns of restraining and operating coil
D. fault current and restraining coil current
18) The bridge used to measure insulation of cable isA. Wien
B. Schering
C. Maxwell
D. Kelvin
19) In a synchronous motor ,the inverted curve represent the relation betweenA. Field current & Armature current
B. Armature curret & Power factor
C. Field current & Power factor
D. none of these
20) If the rotor power output of 3 phase induction motor is 12 Kw ,the rotor
copper losses at slip of 5% will beA. 600 W
B. 625 W
C. 650 W
D. 700 W
21) What are the factors on which the hysteresis loss depend
A. frequency
B. frequency&fluxdensity
C. magnetic flux intensity
D. none of these
22) The MOSFET switch is onstate may be considered equivalent toA. capacitor
B. inductor
C. resistor
D. battery
23) Power is drawn from a source at p.f. 0.8,Pav=200 W,the reactive power is
given by
A. 200 VAR
B. 150 VAR
C. 160 VAR
D. 120 VAR
24) VSWR can have value of betweenA. 0&1
B. 1&∞
C. 0&∞
D. -1&1
25) In single pulse modulation PWM inverters sixth harmonic can be eliminated if
pulse width equal toA. 30 Degree
B. 60 Degree.
C. 36 Degree
D. 1080 Degree
26) Equal area criterion gives the information regardingA. Stability region
B. relative stability
C. absolute stability
D. swing curves
27) A megger is used for measurement ofA. Low resistance
B. medium resistance
C. High valued resistance, particularly insulation resistance
D. all of these
28) The high torque by weight ratio in an analog indicating instrument indicates
A. High friction loss
B. Fast response.
C. Slow response.
D. None of above
29) In active filter which element is absent
A. inductor
B. capacitor
C. both
D. resistor
30) Peterson coil is used in
A. dc power transmission line
B. ac transmission line
C. dc motor
D. both a and b
31) How does the depth of laying affect the current carrying capacity of cables
A. decreases
B. increases
C. unchanged
D. doubles
32) The phase of lead compensator of the system G(s)= s+a/s+b is maximum at
A. ab
B. &radic ab
C. &radic a/b
D. a/b
33) In a balanced wheatstone bridge if positions of detector and source are
interchanged then bridge will still remain balanced . The inference can be drawn
from
A. duality
B. reciprocity theorem
C. compensation theorem
D. both a and b
34) When compared a 1st order LPF a 2nd order LPF has
A. lower voltage gain
B. higher voltage gain
C. higher cut off frequency
D. faster drop in filter response
35) Load frequency control is achieved by properly matching the individual
machine
A. turbine inputs
B. reactive powers
C. generated voltages.
D. generator ratings.
36) In O.C test which side is kept open
A. h.v side
B. l.v side
C. any one
D. both
37) ALL DAY ENERGY EFFICIENCY is related to which of the transformer
A. distribution transformer
B. C.T
C. P.T
D. power transformer
38) At slip s=1 torque developed in machine is
A. starting torque.
B. maximum torque
C. electromagnetic torque
D. none
39) Strain insulator is used for voltage level of
A. >33KV
B. <11KV
C. >66KV
D. 132KV
1051) Effect of temperature on internal resistance of a battery
A. directly proportional
B. inversely proportional
C. no effect
D. none of these
40) What dielectric material are used in the capacitor used for pf correction
A. vacuum
B. oil impregnated paper
C. mica
D. glass
41) dummy strain gauges are used for
A. compensation of temperature changes
B. increase sensitivity of bridge
C. calibration purpose
D. all
42)LEAD NETWORK is used to improve
A. improve transient response
B. both a and c
C. increase bandwith
D. improve steady state response
43) De Sauty bridge best suited for
A. capacitors with dielectric loss
B. lossless air capacitors
C. high Q
D. low Q
44) For a fixes value of complex power flow in a transmission line having a
sending end voltage V, REAL POWER LOSS will be proportional to
A. V
B. 1/V 22
C. 1/V
D. V 22
45) Q meter works on principle of
A. mutual inductance
B. series resonance
C. self inductance
D. parallel resonance
46) The positive reactance equals to negative sequence reactance if equipment is
A. motor
B. transformer and transmission line
C. generator
D. all of these
47) A synchronous generator is feeding a zero power factor(lagging) load at rated
current,the armature reaction is
A. magnetizing
B. cross -magnetizing
C. ineffective
D. demagnetizing.
48) A moving iron voltmeter is connected across thwe voltage source whose
instantaneous value V(t)=5+10cos(314+30 degree).The reading of the meter isA. √(75) V.
B. 15 V .
C. √(125) V .
D. 5 V.
49) How many Flipflops are required to build a binary counter circuit to count
from 0 to 1023.
A. 6
B. 24
C. 10
D. 12
50) If a shunt generator delives 100 A at 200V, and the resistances of the shunt
field and armature are 100 ohms. And 0.01 ihms respectively, the generator e.m.f.
will be
A. 212 V
B. 205 V
C. 210 V
D. 201.02 V
51) The bridge method commonly used for finding mutual inductance is
A. Schering bridge
B. Heaviside Campbell bridge
C. De-saulty bridge
D. Wien bridge
52) High voltage DC transmission (HVDC) transmission is mainly used for
A. Bulk power transmission over very long distances
B. interconnecting Two systems with the same nominal frequency
C. eliminating reactive power requirement in the operation
D. minimizing harmonics at the converter stations
53) In order to increase the limitation distance of transmission line the following
can be used
A. Shunt reactors & series capacitors
B. series reactors& shunt capacitors
C. Synchronous condensers
D. Tap- changing Transformers
54) A compensated wattmeter has its reading corrected for error due to theA. Frequency
B. friction
C. power consumed in potential coil
D. power consumed in current coil
55) A long wire composed of a smooth round conductor runs above and parallel to
the ground (assumed to be a large conducting plane). A high voltage exists
between the conductor and the ground. The maximum electric stress occurs at
A. lower surface of the conductor
B. upper surface of the conductor
C. the ground surface
D. midway between the conductor and ground
56) If a fault occurs on any feeder, the fault current is
A. much higher than with unsectional busbar
B. much lower than with unsectional busbar
C. equal to unsectional busbar
D. none of these
57) Current chopping mainly occurs in
A. Airblast circuit breaker
B. Vaccum circuit breaker
C. SF6 circuit breaker
D. Oil circuit breaker.
58) On a power system network the load is increasing represents the value of
impedance
A. decrease
B. increase
C. remains constant
D. none of above
59) In characteristic impedance of a transmission line if load impedance of a
transmission line is equal to the load impedance then
A. all the energy sent will observed by the load
B. the system will resonate badly
C. all the energy sent will pass to earth
D. all energy will lost in transmission line as transmission losses
60) When an electric train is moving down a hill, the dc motor will operate as dc
A. series motor
B. series generator
C. shunt motor
D. shunt generator
61) In variable speed dc motor drive the armature voltage control leads to
A. constant power operation
B. constant torque operation
C. variable torque operation
D. randomly varying power operation
62) A four quadrant operation requires
A. two full converters in series
B. two full converters connected in parallel
C. two full converter connected in back to back
D. two semi converters connected in back to back
63) Speed control by variation of field flux results in [A.M.I.E sec B elec drives &
their control summer 1994]
A. constant power drive
B. variable power drive
C. constant torque drive
D. none of the above
64) A cascade of three linear time invariant systems is causal & unstable. From
this we conclude thatA. Each system in the cascade is individually caused & unstable .
B. At least one system is unstable & at least one system is causal..
C. At least one system is causal & all systems are unstable .
D. The majority are unstable & the majority are causal.
65) In the integral control of the single area system frequency error is reduced to
zero. Then
A. Integrator output & speed changer position attain a constant value.
B. Integrator output decreases but speed changer position moves up.
C. Integrator output increases but speed changer position also becomes down.
D. Integrator output decreases &speed changes position also comes down.
66) Which type of motors are preferred in lifts?
A. dc compound motors.
B. dc series motors.
C. dc shunt motors.
D. none of the above.
67) In traveling cranes for crane travel, trolley and boom hoist which motor is
preferred?
A. stepper motor
B. slip ring induction motor
C. dc differential compound motor
D. synchronous motor
68) In lathes, milling and grinding machines which motor will preferred?
A. dc shunt motors
B. cage induction motor
C. synchronous motor
D. either A or B
69) Which of following motor is preferred for belt conveyor?
A. slip ring induction motor
B. synchronous motors
C. reluctance motor
D. universal motor
70) If the rated voltage from the power lines is applied to the primary of a single
phase transformer which is operated on no-load, thenA. Both input voltage &current are sinusodial.
B. Both input voltage & current are nonsinusodial
C. input voltage is nonsinusodial & input current is sinusodial
D. input voltage is sinusodial & input current is non sinusodial
71)nonlinear system will improve
A. linear input
B. system response
C. input amplitude
D. periodicity
72) controllability involves the matrices
A. system matrix and input matrix>
B. input matrix and output matrix>
C. system matrix and output matrix>
D. transmission matrix and input matrix
73)observability involves matrices
A. system matrix and input matrix
B. input matrix and output matrix
C. system matrix and output matrix
D. transmission matrix and input matrix
74) The air gap between stator and the rotor of the 3φ induction motor is kept
A. as wide as possible
B. as small as possible
C. depends on the material of stator and the rotor
D. air gap does not matter
75) What is power factor of a 3φ induction motor at no load?
A. high
B. low
C. equal to 1
D. same as full load
76) Unbalanced supply voltage given to a 3φ,delta connected induction motor will
cause
A. Negative sequence current
B. Less heating of the rotor
C. Less heating of the rotor
D. All of these
77) Exciting current of an Induction motor is
A. Higher than power transformer
B. Lesser than power transformer
C. Equal as power transformer
D. None of these
78) Main bus bar protection scheme is /are
A. differential protection
B. both fault bus and differential protection
C. fault bus protection
D. none of these
79)THIRD PIN of a 3 pin plug is thicker and longer due to
A. for designing purpose
B. for protection purpose
C. all pins are of same size
D. none of these
80) The dc motor which can provide zero speed regulation at full load without any
controller , is
A. differential compound
B. series
C. cumulative compound
D. shunt
81) Distributed winding and short chording employed in AC m/c will result in
A. increase in emf and reduction in harmonics
B. decrease in emf and increase in harmonics
C. increase in both
D. decrease in both
82) The major cause of creeping in an energy meter is
A. over compensation for friction
B. excessive voltage across potential coil
C. mechanical vibrations
D. stray magnetic field
83) In case of a D.C shunt motor under no load condition the air gap flux
A. keeps varying.
B. increases.
C. remains constant.
D. decreases.
84) The stationary alternator must not be connected to live bus bars because it
will results—————-
A. short circuit
B. open circuit
C. nothing will happen
D. floating
85) Floating of alternators with bus bars occurs at when
A. synchronized generated emf is less than the bus bar voltage
B. synchronized generated emf is greater than the bus bar voltage
C. synchronized generated emf is equal to the bus bar voltage
D. none of above
86) In double cage induction motor, the inner cage offers
A. high resistance and low reactance
B. low resistance and high reactance
C. low resistance and low reactance
D. high resistance and high reactance
87) Corona effect can be minimizedA. irregular surface of conductors.
B. stormy weather.
C. small spacing between conductors.
D. large spacing between conductors
88) Ampere second is the unit of
A. conductance
B. power
C. energy
D. charge
89) Rotating magnetic field is produced in an induction motor because of
A. stator winding.
B. rotor winding.
C. either stator winding or rotor winding.
D. none of the above.
90) The pressure coil of a dynamometer type wattmeter is
A. highly resistive
B. highly inductive
C. purely resistive
D. purely inductive
91) The bridge method is used for finding mutual inductance is
A. Schering bridge
B. Heaviside Campbell bridge
C. De Sautee
D. Wine’s
92) In relay coil which is usedA. current transformer
B. potential transformer
C. power transformer
D. instrument trnansformer
93) Which alternator more suitable for high-speed system ?
A. Salient pole
B. no salient pole
C. Both (a)& (b)
D. none of these
94) The reduced air gap results in an increase
A. cost of operation
B. breaking torque
C. starting torque
D. power factor
95) In IM the rotor laminations can be—————than stator laminations.
A. thicker
B. thinner
C. sipper
D. rotor can’t have any laminations.
96) Shunt compensation in an EHV system used to
A. reduce fault level
B. Improves the voltage profile
C. improves stability
D. improves the protection of the line
97) What happens if fifth multiples of harmonics is given to induction motor?
A. it will rotates in reverse direction.
B. fail to start.
C. it will rotates in normal operation.
D. either short circuit or open circuit occurs.
98) When transformers or switchgears are to be installed in a line, the poles used
are
A. H TYPE
B. B TYPE.
C. M TYPE
D. J TYPE.
99) The armature resistence of the dc motor is generally of the range:
A. 100 ohm
B. 0.5 ohm
C. 0.1 ohm
D. 50 ohm
100) Insulators are required to withstand in
A. mechanical stress
B. electrical stress
C. both mechanical stress and electrical stress.
D. none of above
101) If the length of cable decreases then insulation resistance
A. increases
B. decreases
C. remains unchanged
D. none of above
102) A line which connects between substation and distribution transformer is
A. secondary feeder
B. primary feeder
C. sub transmission feeder
D. none of these.
103)Armature reaction in dc motor results.
a) Decrease in speed
b) Increase in speed
c) short circuit
d) 0pen circuit
104) What happens if shunt capacitance is reduced
A. string efficiency reduces
B. string efficiency increases
C. doesn’t affect string efficiency
D. may results in short circuit
105) Conductor configuration determines
A. capacitance
B. inductance
C. voltage
D. current
106) Conductor is varying and field is fixed then emf will induces. This principle is
called
A. dynamically induced emf.
B. static induced emf.
C. both A and B.
D. none of the above.
107) For high current and low current rating which winding is employed to DC
machine
A. lap winding.
B. wave winding.
C. both lap and wave winding.
D. none of above
108)
Turbines
a. pelton wheel turbine
specific speed (in s.i. units)
g. 50 to 250
b. Kaplan turbine
h. up to 50
c. Francis turbine
i. 255 to 866
A. a-g, b-h, c-i
B. a-h, b-i, c-g
C. a-i, b-g, c-h
D. none of above
109) Why HV winding is always placed above the LV winding in a core type
transformer?
A. to reduce copper cost
B. to reduce insulation cost
C. to provide better cooling
D. to provide more mechanical strength
110) When a transformer is loaded, the secondary terminal voltage drops. That
means power factor is
A. zero
B. leading
C. unity
D. lagging
111) The main purpose of providing tertiary winding in a three phase
transformer
A. to suppress harmonic voltages and to limit voltage unbalance when the main
load is asymmetrical
B. to inter connect three supply systems operated at different voltages
C. to carry adding extra load to the transformer which for some reason must be
kept isolated
D. none of the above
112) If input of a transformer is square wave the output will be
A. puled wave.
B. square wave.
C. triangular wave.
D. sine wave.
113) The leakage flux in a transformer depends upon
A. the applied voltage
B. the load current
C. the frequency
D. the mutual flux
114) In a core type transformer
A. HV winding is placed nearer to the core limb.
B. LV winding is placed nearer to the core limb.
C. Any of the LV or HV can be placed nearer to the core limb.
D. HV and LV windings are placed in different core limbs.
115) Transformers operating in parallel will share the load depending upon their
A. Leakage reactance.
B. Rating.
C. Efficiency.
D. Percentage impedance.
116) In a transformer the coils of primary and secondary are placed
concentrically to achieve
A. reduced leakage flux between primary and secondary winding
B. reduced copper losses in the winding
C. reduced insulation cost of the windings
D. reduced voltage per turn in the winding
117) Which of the following losses remain constant during normal operation of
transformer?
A. Copper loss
B. Core loss
C. Stray loss
D. All losses in transformer vary with load
118) Which of the following losses varies with load in transformer?
A. Copper loss
B. Hysteresis loss
C. Eddy Current loss
D. All losses in transformer vary with load.
119) If the air gap of IM is increased, ____________ will increase.
A. air gap flux.
B. speed
C. magnetizing current
D. power factor
120) 3rd harmonics are eliminated in induction motor by using
A. V connection
B. delta connection
C. star connection
D. zig-zag connection
121) The electrical conductivity of metal is typically of the order of (in ohm − 1m − 1)
A. 107
B. 105
[UPSC
C. 10 − 4
D. 10 − 6
122) Pure metal generally have
A. high conductivity and low temperature coefficient
B. high conductivity and large temperature coefficient
C. low conductivity and zero temperature coefficient
D. low conductivity and high temperature coefficient
123) The temperature coefficient of resistance of an insulator is
A. positive and independent of temperature
B. negative and dependent on temperature
C. negative and independent on temperature
D. positive and dependent on temperature