Assistant Electrical Inspector Previous Questions Paper 2007
1) Swinburne test can be applied only for ?
A. shunt motor
B. shunt and compund motor
C. series motor
D. series and shunt motor
2) The errors committed by a person in the measurement are ?
A. random error
B. environmental error
C. gross error
D. instrumental error
3) Which of the following is an ideal voltage source ?
A.voltage indepedent of current
B. current independent of voltage
C. voltage depends upon current
D. current depends upon voltage
4) A power MOSFET has three terminals called ?
A. collector, emitter and base
B. collector, emitter and gate
C. drain, source and gate
D. drain, source and base
5)Sine wave A has a positive going zero crossing at 30 degrees. Sine wave B has a positive going zero crossing at 45 degrees. What is the phase angle between two signals ?
A. 75 degrees
B. 15 degrees
C. 45 degrees
D. 30 degrees
6)The major cause of creeping in an energymeter is ?
A. stray magnetic field
B. over compensation of friction
C. mechanical vibration
D. excessive voltage across the potential coil
7)In a certain series RC circuits, Vr = 8V and Vi = 6 V, what is the magnitude of the total voltage ?
A. 10 V
B. 14 V
C. 8 V
D. 6 V
8) A 160 KVA and 315 KVA transformers are operated in parellel. To share the load in propotion to their ratings, their?
A. copper losses should be equal
B. impedences should be equal
C. efficiencies should be equal
D. p.u impedances should be equal
9) Which of the following theorems is applicable for both linear and non-linear circuits ?
A. none of the above
10) The three resistance each of 9 ohms are connected in delta. The equivalent star arrangement will have each resistance values ?
A. 18 ohms
B. 3 ohms
C. 27 ohms
D. 9 ohms
11) The positive sequence component of voltage at the point of fault is zero when it is a ?
A. 3-phase fault
B. L-L fault
C. L-G fault
D. L-L fault
12) A 10KVA, 200/400V single phase transformer is supplying its rated current of 25 A. The input current is likely to be ?
B.more than 50 A
D.less than 50 A
13) The rotor power output of 3-phase induction motor is 30KW and the corresponding slip is 4%. The rotor copper loss will be ?
14) As k approaches zero the root loci approach towards ?
A.break in point
B.open loop poles
C.break away points
D.open loop zeroes
15) When an SCR is conducting, the voltage drop across it is about ?
16) In the measurement of three phase power by two-wattmeter method, if one of the wattmeter reads negative, the power factor of the load is ?
C. less than 0.5
D. greater than 0.5 but less than 1
17) The Bode plot approach is applicable to ?
A. any network
B. none of the above
C. non-minimum phase network
D. minimum phase network
18) A salient pole synchronous machine has maximum power output when power angle is ?
A. more than 90 degree
B. less than 90 degree
C. either 90 degree or more
D. 90 degree
19) The installed generating capacity of Idukky hydroelctric station is ?
A. 1000 MW
B. 780 MW
C. 660 MW
D. 720 MW
20) In a non-salient pole synchronous machine the distribution of field mmf around the air gap is a ?
A. sinusoidal wave
B. rectangular wave
C. flat topped stepped wave
D. stepped triangular wave
21) An induction motor takes a line current of 80A when started by direct switching. If an auto transformer with 50% tapping is used, the line current would be ?
A. 40 A
B. 80 A
C. 50 A
D. 20 A
22) Under full load condition, the power factor of rotor circuit of a 3-phase induction motor is ?
A. about 0.2 lagging
B. almost unity
C. about 0.2 leading
D. about 0.5 lagging
23) For a certain load, the true power is 100 W and the reactive power is 100 VAR. What is the apparent power ?
B. 141.4 VA
C. 100 VA
D. 200 VA
24) In an induction type meter, maximum torque is produced when the phase angle between two fluxes are ?
A. 0 degree
B. 30 degrees
C. 90 degrees
D. 45 degrees
25) The diagonal elements of a nodal admittance matrix are strengthened by adding ?
C. shunt inductances
D. shunt capacitors
26) The time period of an alternating equality is 0.04 seconds. Its frequency will be ?
A. 100 Hz
B. 25 Hz
C. 50 Hz
D. 0.04 Hz
27) A single-phase fully controlled bridge rectifier is fed by a source having inductance. The output voltage during overlap period is ?
C. 0.5 Vm – voltage drop across inductance
D. 0.5 Vm
28) As the temperature rises, the resistance of carbon ?
C. becomes zero
D. remains unchanged
29) For an SCR dv/dt protection is achieved through the use of ?
A. R in series with SCR
B. C across SCR
C. R-C across SCR
D. R-L in series with SCR
30) The characteristics equation of a feedback control system is s(square)+ks(square)+5s+10 = 0. The value of k for the system to be critically stable is ?
31) A milli-ammeter of resistance 200 ohm connected in series with a circuit consumes 0.2 mW. If it is replaced with a milli-ammeter of 400 ohm resistance, the power consumption will be. ?
A. 1 mW
B. 0.8 mW
C. 0.4 mW
D. 0.2 mW
32) For a fixed load on the shaft, the armature current of a synchronous motor is minimum when the pf is: ?
A. leading or lagging but not unity
C. less than 1 and leading
33) The presence of earth in case of overhead lines. ?
A. increses th inductace
B. increases the capacitance
C. decreases the capacitance
D. decreses the inductance
34) A voltmeter has uniform scale, it is ?
A. moving coil permanent maganet
B. moving coil dynamometer type
C. induction type
D. moving iron type
35) If an induction motor with certain ratio of rotor to stator slots runs at 1/7th of the normal speed, the motor is said to be?
36) A 4 pole dc machine has a lap winding. This winding is removed and then a wave winding with the same number of turns is put. The induced e.m.f will ?
B. remains the same
C. may increase or decrease
37) The unit protection scheme provides. ?
A. remote protection
B. back up protection
C. simultaneous protection
D. primary protection
38) In an ac circuit if voltage V = (a+jb) and current i = (c+jd), then the power is given by ?
39) An auto-transformer having a transformation ratio of 0.7 supplies a load of 20 KW. The power transferred inductively from primary to secondary is ?
A. 6 KW
C. 20 KW
D. 14 KW
40) Megger is used for ?
A. measuring current
B. measuring power
C. measuring voltage
D. measuring insulation resistance
41) Which generators require an equilliser bar for parallel operation?
A. series and compound
42) The number of disc in a string of insulators for 400 kV ac overhead line lies in the range of ?
A. 15 to 16
B. 22 to 23
C. 9 to 10
D. 32 to 33
43) A 0-100mA PMMC ammeter reads 80mA in a circuit. If its bottom control spring snaps suddenly, the meter will read nearly ?
44) Laplace transform of the output response of a linear system is the system transfer function when the input is ?
A. a ramp signal
B. a step signal
C. a sinusoidal signa
D. an impulse signal
45) Load flow study is carried out for ?
A. fault calculations
B. stability studies
C. system planning
D. load frequency control
46) The neutral current in a balanced three-phase four wire star connected load is ?
B. root 3 IL
D. root 3 Iph
47) The form factor is the ratio of ?
A. average value to rms value
B. peak value to rms value
C. peak value to average value
D. rms value to average value
48) Ferranti effect on long overhead line is experienced when it is ?
A. on full load at 0.95 lag
B. on full load at 0.8 pf lag
C. lightly loaded
D. on full load at upf
49) A forward voltage can be applied to an SCR after its ?
A. anode voltage reduces to zero
B. gate recovery time
C. reverse recovery time
D. anode current reduces to zero
50) As the load on a synchronous motor is increases, the torque angle ?
A. remains the same
D. may increase or decrease
51) A single –phase transformer is rated at 100 KVA, 5000/250V. The full load copper losses are 1KW. The load KVA for maximum efficiency is: ?
A. 141.4 KVA
B. 50 KVA
C. 100 KVA
D. 70.7 KVA
52) The usual value of slip of a 3-phase induction motor at full load is about ?
53) Hunting is prevented in a 3-phase synchronous motor by ?
A. short-pitch winding
B. compensating windings
C. dummy coils
D. damper winding
54) The span of a zero centered ammeter having a scale from -10A to +10A is ?
A. 10 A
B. 20 A
C. 0 A
55) The average load factor of thermal power plants in India is ?
56) The permissible variation of frequency in power system is ?
A. + or – 1%
B. + or – 3%
C. + or – 2%
D. + or – 5%
57) Moving iron and PMMC instruments can be distinguished from each other by looking at ?
B. scale range
D. terminal size
58) Determine the current if a 10 C charge passes a point in 0.1 sec ?
A. 0.01 A
B. 10 A
C. 100 A
D. 1 A
59) The practical unit of electrical is ?
60) Sensitivity of an instrument is independent of ?
A. hysterisis or dead band
B. frequency response
C. amplitude distortion
D. all of the above
61) The characteristic equation of a system is s(square)+4.8+36 = 0. Its damping ratio is ?
62) A single phase cyclo-converter with center tapped input transformer requires ?
A. 8 SCR’s
B. 2 SCR’s
C. either 2 or 8 SCR’s
D. 4 SCR’s
63) A load commutated chopper circuit has ?
A. four thyristors
B. maybe equal or unequal
C. two thyristors
D. are always equal
64) Electrostatic instruments are essentially ?
65) A dc generator beyond critical resistance will generate ?
A. maximum voltage
B. maximum voltage and maximum current
C. maximum power
D. no voltage
66) An alternator is delivering its rated current at rated voltage and 0.8 pf lagging. If it is required to deliver rated current at rated voltage at 0.8 pf leading, the required excitation will be ?
C. more or less
D. the same
67) The highest transmission voltage in Kerala is ?
A. 400 kV
B. 110 kV
C. 220 kV
D. 700 kV
68) The origin for the investigation of closed loop stability in relation to Nyquist criterion is ?
69) Number of slip-rings in a 3-phase synchronous motor will be ?
A. 3 or 4
70) The insulation resistance of a cable of length 20km is 1 ohm, its insulation resistance for 100 km length is?
A. 5 megaohm
B. 0.2 ohm
C. 2.5 megaohm
D. 1 megaohm
71) If the time of operation of a relay for unit TMS is 10 seconds the time of operation for 0.5 TMS will be ?
A. 10 sec
B. 5 sec
C. 15 sec
D. 20 sec
72) The dimension of power are ?
73) The breadth factor of a 3-phase ac winding is about ?
74) The transfer function of a unity feedback system is 10/(s+1). For unit step input the steady state error will be ?
75) The range of a dc milli-ammeter can be extended by using a ?
A. shunt of low resistance
B. series high resistance
C. shunt of high resistance
D. series low resistance
76) The insulation of modern EHV lines is designed based on ?
A.the lighting voltage
B.the switching voltage
77) The voltage of a particular bus can be controlled by controlling the ?
A. reactive power of the bus
B. phase angle
C. active power of the bus
D. phase angle and reactive power
78) For a matrix A= row 1 [1 4], row 2 [ -2 -5], the eigen values are ?
79) A digital voltmeter measures ?
A. average value
B. peak value
C. rms value
D. peak to peak value
80) A 100V voltmeter has an accuracy of 5% on full scale. The percentage error while measuring 50 V will be ?
81) A three-phase 100 KVA transformer is composed of three seperate transformers connected in delta-delta. If one of the units get damaged and it is operated in open delta; the rating will be:?
A. 50 KVA
B. 86.6 KVA
C. 57.7 KVA
D. 100 KVA
82) The rectifier type instrument is not free from ?
A. temperature error
B. frequency error
C. wave shape error
D. all of the above
83) Integrating meters are used for the measurement of ?
84) For a synchronous phase modifier the load angle is ?
A. 0 degree
B. 95 degrees
C. 30 degrees
D. 60 degrees
85) In case of a 3-phase short circuit in a system, the power fed into thr system is ?
A. active and reactive both equal
B. mostly reactive
C. mostly active
D. reactive only
86) Clamp-on-ammeter is used for measurement of ?
A. small direct current
B. large direct current
c. large alternating current
D. small-alternating currents
87) Graphite is used in nuclear power plants as a ?
88) A square wave type voltage of peak magnitude 200 V is measured by a moving iron voltmeter. It will read ?
A. 400 V
B. 100 V
C. 600 V
D. 200 V
89) The impedance value of a generator is 0.3pu on a base value of 22kV, 150MVA. The impedance value for a base value of 11kV, 50 MVA is ?
90) In a dc machine, the coil span ?
A. must be equal to pole-pitch
B. can never be equal to pole-pitch
C. may or may not be equal to pole pitch
D. is equal to half pole-pitch
91) The convergence characteristics of the Newton-Ralphson method for solving a load for problem is ?
92) A single –phase transformer is rated at 100 KVA, 5000/250V. The full load copper losses are 1KW. The load KVA for maximum efficiency is: ?
A. 141.4 KVA
B. 50 KVA
C. 100 KVA
D. 70.7 KVA
93) A transformer can have zero regulation at ?
A. lagging pf
B. leading pf
C. zero pf
D. unity pf
94) In a single-phase semi converter, for continuous conduction free wheeling diode conducts for ?
B. firing angle alpha
C. alpha + pi
D. pi – alpha
95) The resistance of a parallel circuit consisting of two resistors is 6 ohms. When one of the resistors is removed the effective resistance becomes 9 ohms. The resistance of the removed wire is ?
A. 18 ohms
B. 3 ohms
C. 15 ohms
D. 12 ohms
96) A fault is more severe from the view point of RRRV if it a ?
A. long line fault
B. either long line or medium length line fault
C. short line fault
D. medium length line fault
97) The cheapest instrument for dc measurement is ?
B. moving iron
D. hot wire
98) The location of the closed loop conjugate pair of pole on jw axis indicates the system is ?
C. marginally stable
D. critically stable
99) McMurray full bridge inverter uses ?
A. none of the above
B. complementary communication
C. natural communication
D. auxilliary communication
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