1/100
In synchronous motor, minimum armature current corresponds to
2/100
The angle between the synchronously rotating stator flux and rotor poles of a synchronous motor is known as
3/100
An electric motor in which both the rotor and stator fields rotate at same speed is called
4/100
Breather of a transformer has
5/100
During resistance welding the heat produced at the joint is proportional to
6/100
The maximum starting torque of a 3-phase induction motor is obtained when the rotor resistance is
7/100
The motor usually used for driving a refrigerator is
8/100
The motor, which is not self starting is
9/100
Skewing of rotor slots in induction motor is to
10/100
The ratio between rotor input, rotor output and rotor Cu losses is
11/100
The advantage of capacitor start motor compared to standard split phase winding motor is that
12/100
A 4-pole, 50 Hz induction motor is found to be running on full load at a slip of 5%. The speed of the induction motor is
13/100
In the circuit given below, the current 1 is given by
14/100
The complex power drawn by an inductive circuit is 3000 watts + j4000 VARS. Then the power factor is given by
15/100
The maximum power that a 12V DC source with an internal resistance of 2 ohms can supply to a resistive load is
16/100
The total impedance of the circuit shown is
17/100
The Thevenin's equivalent across AB is given by
18/100
The unit of absolute permitivity of a medium is
19/100
The capacity of a lead acid cell does not depend on its
20/100
Two similar electric charges of IC each ares placed 1 m apart in air. Force of repulsion between them would be nearly ------------ newtons
21/100
Two heaters rated at 1000 W, 250 V ench, are connected in series across a 250 V, 50 Hz AC mains The total power drawn from the supply would be
22/100
A semiconductor is electrically neutral because
23/100
Materials which are good conductors of both heat and electricity are
24/100
Economisers in thermal power station are used to heat
25/100
Of all the power plants,minimum quantity of fuel is requiered in
26/100
Load factor is given by the ratio of
27/100
Area covered by the load duration curve is equal to the
28/100
The ideal tariff for any type of consumer is
29/100
Power factor can be improved by installing such a device in parallel with load which takes
30/100
In an interconnected grid system, the diversity factor of the whole system
31/100
Which portion of the transmission system is more prone to faults?
32/100
A fuse is normally a
33/100
Buchholz relay is used for the protection of
34/100
. Who relays have an R-X plane characteristic depicted by
35/100
Which one of the folowing is provided with arcing horns
36/100
Insulators, that are med at the dead ends or to change the direction of transmission line are
37/100
The generalised constans A and D of the transmission line have
38/100
In a string suspension insulation the maximum voltage appears across the
39/100
The most common system for secondary distribution of 400/230V is B
40/100
If the length of a cable is doubled, then its capacitance is
41/100
For higher transmission voltages
42/100
42. During _____type of braking motors are reverse connected to supply
43/100
Ring main distribution system is preferred to a radial system, because
44/100
String efficiency is increased by using
45/100
If the sag in an overhead line increases, tension in the line _______
46/100
A SCR has____PN junctions
47/100
A single diode operates as a
48/100
In phase controlled rectification, power factor
49/100
The duty cycle of a step down chopper is
50/100
A cyclo-converter is
51/100
. It is advisable to control speed of induction motor by maintaining
52/100
in digital computers, a BYTE denotes
53/100
In order to enter a control word in the control register of 8255, the instruction to be used is
54/100
A Zener diode is operated in the
55/100
The output of two-onput AND gate is 1
56/100
56. A.B.C is equivalent to_____
57/100
The devices commonly used for making digital circuits are
58/100
.A CRO can display
59/100
The main advantage of crystal oscillator is that its output is
60/100
The input impedance of the operational amplifier is
61/100
ICs are usually made of
62/100
The most modern method of heating used in food processing is
63/100
The illumination at various points on a horizontal surface illuminated by the same source varies as
64/100
Which of the following is present inside the fluorescent tube?
65/100
The value of coefficient of adhesion will be high when rails are
66/100
.The speed time curve for urban service locomotive has no
67/100
Long distance railways operate on
68/100
The machine having heavy fluctuation of load is
69/100
The best suited motor for rolling mills is
70/100
PLC stands for
71/100
The commutator segments of a dc machine are insulated form each other by a thin layer of
72/100
A 200V DC machine has an armature resistance of 0.02 ohms. The difference in the induced voltages when the machine is running as a motor and as a generator and carrying a full load current of 200 A, is
73/100
Negative voltage regulation is obtained in the following DC generator
74/100
In a 4-pole, 36 slot d.c. armature, the coil span of 180 electrical degrees will be obtained when the coil occupies
75/100
The essential condition for stable parallel operation of two identical DC generators is that ,they should have
76/100
In a DC series motor, the field flux is
77/100
In a DC shunt motor, at 20A of load current the torque developed is 30 Nm. If the load current is doubled, the torque changes to
78/100
Hysteresis and Eddy current losses in electrical machines depend on
79/100
The efficient way of obtaining damping torque in electrical instruments is
80/100
Induction type wattmeter operation is based on
81/100
Basically, a megger is
82/100
The thermocouple instrument will measure
83/100
The load sharing between two transformers operating in parallel, is according to their
84/100
The primary and secondary induced emi's, E₁and E₂ in a two winding transformer are always
85/100
A 200 KVA transformer has an iron loss of 1 kW and full load copper loss of 2 kW. The load RVA, corresponding to maximum efficiency is
86/100
The main purpose of performing open-circuit test on a transformer is to find its
87/100
When compared to a ∆-∆ three-phase transformer bank, the capacity of V-V transformer bank is
88/100
The equivalent primery resistance of the transformer with k = 5m 0.1 ohm. When it is referred to secondary, then it becomes
89/100
in the emf equation of a transformer, the flux involved is
90/100
An ac current given by i=14 .14 sin (wt + π / 4) has a.r.m.s value of
91/100
The reactance of a capacitor to alternating current of frequency 50 Hz is 10 Ω if the frequency is increased in 100 Hz, then its reactance becomes
92/100
The form facut in a .c means the ratio of
93/100
In two wattmcier method of measuring 3-phase power and power factor is 0.5, then one of the wantmeter will read
94/100
A coil of resistance 100 Ω and inductance 100 uH is connected to series with 100 pF capacitor across a 10V variable trequency supply. The resonance frequency of the circuit is
95/100
A parallel circuit consists of 2.5 uF capacitor and a coil whose resistance and 15Ω and 260 mH respectvoly, the dynamic impedance of the circuit is
96/100
At leading power factor the armature flux in an alternator _____the rotor flux
97/100
The distribution factor is defined as the ratio of
98/100
Zero power factor method of an alternator is used to find its
99/100
A sinewave has a frequency of 50 Hz. Its angular frequency is_____ redians/seconds
100/100
If an alternator winding has fractional pitch ov 5/6 , then the coil span is
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