ELECTRICAL ENGINEERING BITS-4

301.

In India diesel locomotives are manu¬factured at
 Varanasi 

302.

Flux density under trailing pole tips in case of generator will _______?
 increase 

303.

A current of 16 amperes divides between two branches in parallel of resistances 8 ohms and 12 ohms respectively. The current in each branch is

 6.4 A, 9.6 A

304.

Transfer function of a system is used to calculate which of the following ?

 The output for any given input

305.

Electric field strength of charge _______
 Decrease with square distance. 

306.

Resistance variation method of temperature control is done by connecting resistance elements in

 all of these ways

307.

Which of the following can be measured by the use of a tacho-generator ?
 Speed 

308.

An unexcited single phase synchronous motor is
 reluctance motor. 

309.

In which of the following, voltage regulation may be zero or negative

 leading power factor

310.

Reluctance motor is a

 self starting type synchronous motor

311.

Which of the following happens when star-delta starter is used ?

 Both starting voltage is reduced and starting current is reduced

312.

Superconducting metal in super conducting state has relative permeability of
 zero 

313.

Centrifugal switch is absent in which of the single phase induction motor?

 PSC (permanent split capacitor) motor.

314.

The resistance in the circuit of the moving coil of a dynamometer wattmeter should be
 high 

315.

The skin effect of conductor will increase when _____?

 resistivity decrease

316.

The type 1 system has ______ at the origin.
 simple pole 

317.

A controller, essentially, is a
 comparator 

318.

A 3-phase, 2 pole, 12 slot synchronous machine is operating at synchronous speed. Find the slot angle?
 30° 

319.

Which of the following methods of heating is not dependent on the frequency of supply ?
 Electric resistance heating 

320.

Which of the following relation is correct?

 Xd > Xq

321.

Which of the following motors is preferred when quick speed reversal is the main consideration ?
 D.C. motor 

322.

A phase lag lead network introduces in the output

 lag at low frequencies and lead at high frequencies

323.

Due to which of the following reasons excessive bond width in control systems should be avoided ?

 Noise is proportional to band width

324.

A resistance having rating 10 ohms, 10W is likely to be a

 wire wound resistor

325.

________has least range of speed control.
 Synchronous motor 

326.

Which of the following material has nearly zero temperature co-efficient of resistance?
 Manganin 

327.

For radiant heating around 2250°C, the heating elements are made of
 tungsten alloy 

328.

The action of electromagnetic machines can be related to which of the following basic principles ?

 Induction 

329.

The load cycle for a motor driving a power press will be

 intermittent and variable load

330.

In load flow studies PV bus is treated as PQ bus when ________?
 reactive power goes beyond limit 

331.

Cables, generally used beyond 66 kV are

 oil filled

332.

By which of the following the system response can be tested better ?
 Unit impulse input signal 

333.

The total number of strands(N) is concentrically stranded cable with total annular space filled with strands of uniform diameter is given by (if x is number of layers)

 N = 3x²-3x+1

334.

Which of the following motor is used in grinders?
 Capacitor start capacitor run IM. 

335.

A DC generator without commutator is a __________?
 AC generator 

336.

A single-winding single-phase motor has ________ ?

 zero starting torque.

337.

The high voltage winding is usually which of the following type ?

 Cross-over winding with either circular or small rectangular conductors 
 All of these

338.

If an instrument has cramped scale for larger values, then it follows
 logarithmic law 

339.

What is the phase difference between two windings of A.C servomotor ?
 90°. 

340.

Commonly used standard capacitor is

 concentric cylindrical type

341.

For a single phase capacitor start induction motor which of the following is valid?
 Rotation can be changed by reversing main winding terminals. 

342.

In a single phase induction motor, the starting torque developed is proportional to
 V² 

343.

Two infinite parallel metal plates are charged with equal surface charge density of the same plates is.
 Zero.

344.

In which of the following configuration power transferability is higher?

 triangular configuration

345.

A shaded pole single phase induction motor can be used for ???
 personal computers as cooling fan 

346.

A synchronous motor is supplying a load at unity power factor. If the load on the motor is increased keeping its excitation and terminal voltage constant, the power factor will remain the same ??
 will become lagging 

347.

In industries which electrical braking is preferred?
 Regenerative braking. 

348.

Synchronising power of a synchronous motor varies

 inversely as 1/Xs

349.

Cylindrical windings using circular conductors, employed in transformers, are
 multi-layered 

350.

The results of a slip test for determining direct axis (Xd) and quadrature axis (Xq) reactances of a star connected salient pole alternator are given below Phase values: Vmax = 108 V ; Vmin = 96 V Imax = 12 A ; Imin = 10 A Hence the two reactances will be ???

 Xd = 10.8O and Xq = 8O

351.

At transition temperature the value of critical field is
 zero 

352.

For pure resistive load what is the armature reaction?

 cross magnetization

353.

The concept of V/f control of inverters driving induction motors resuls in
 constant torque operation 

354.

Apart from the skin effect the non uniformity of the current distribution is also caused by ??

 proximity effect

355.

______is the reference input minus the primary feedback.
 Actuating signal 

356.

The household energy meter is

 an integrating instrument

357.

Which of the following statement is true for an AC synchronous motor?
 It is a constant speed motor. 

358.

Surge impedance loading of a transmission line can be increased by ___________

 both of these

359.

Varistors are
 non-linear resistors 

360.

For accurate load flow calculations on large power systems, the best method is ??

 N-R method

361.

______ has zero temperature co-efficient of resistance.

 Manganin

362.

Which of the following represents the operating region slips of a 1-phase induction motor?

 0 < S < 2

363.

A good electric contact material should have all of the following properties except
 high resistivity 

364.

Which of the following motors is preferred when smooth and precise speed control over a wide range is desired ?
 D.C. motor 

365.

For intermittent work which of the following furnaces is suitable ?

 Indirect arc furnace

366.

Zero voltage regulation is possible only for__________
 leading power factor 

367.

The power factor will be leading in case of _______
 Dielectric heating. 

368.

In induction motors, the length of air gap in kept as small as mechanically possible is order to have

 high power factor

369.

Which of the following motors has low ratings only?

 shaded pole

370.

In transformers using hot rolled steel, the cross-section of the yoke is made about _____ greater than that of the core

 15 percent

371.

Series field consists of--------number of turns and ---------- conductors respectively.
 less and thick 

372.

The electrostatic stress in underground cables is
 maximum at the conductor and minimum at the sheath 

373.

A direct current can be measured by

 a D.C. potentiometer in conjunction with a standard resistance

374.

A.C. servomotor resembles
 two phase induction motor 

375.

Length of the cable is doubled, its capacitance C will be ________. 
 doubled.

376.

Specified quantities of slack bus are ________?

 V and d

377.

A light bulb draws 300 mA when the voltage across it is 240 V. The resistance of the light bulb is
 800 Q 

378.

The temperature inside a furnace is usually measured by which of the following ?
 Optical pyrometer 

379.

The return circuit for tramcars is through

 rails

380.

In tramways which of the following motors is used ?
 D.C. series motor 

381.

Under excited Synchronous phase modifier works as ______

 shunt reactor

382.

In a cable, the maximum stress under operating conditions is at

 conductor surface

383.

Which feature, while selecting a.motor for centrifugal pump, will be of least significance ?

 Speed control

384.

Quadrature axis synchronous reactance is the ratio of ___________

 Vmin to Imax.

385.

Piezoelectric materials serve as a source of _____ .
 ultrasonic waves 

386.

The tiny block formed by the arrangement of a small group of atoms is called the

 unit cell

387.

In a control system integral error compensation _______ steady state error

 minimizes

388.

Which of the following is the non-linearity caused by servomotor ?

 Saturation

389.

If the diameter of the conductor is increased ??
 the inductance is decreased 

390.

A transmission line has a reactance of 1 Pu is operating at Vs = Vr = 1 Pu. The generator is connected at source end which is delivering 0.5 Pu of active power. Find the load angle?

 30°

391.

An ACSR conductor has a diameter of 2 cm has internal inductance of 0.05 mH/Km. If this ACSR is replaced with another having a diameter of 4 cm then its internal inductance is ___________?

 0.05 mH/Km

392.

Which of the following materials does not have covalent bonds ?
 Metals 

393.

A transmission line has a reactance of 1 Pu is operating at Vs = Vr = 1 Pu. The generator is connected at source end which is delivering 0.5 Pu of active power and the transmission line is compensated with a series capacitance of 0.5 Pu. Find the load angle with series capacitance compensation ?
 14.5° 

394.

The co-ordination number of a simple cubic structure is
 6 

395.

Hysteresis loss and eddy current loss arc used in ____________
 Induction heating of steel. 

396.

Which of the following instruments indicate the instantaneous value of the electrical quantity being measured at the time at which it is being measured ?

 Indicating instruments

397.

Which of the following is/are advantages of N-R method?
 
 both of these

398.

Radiations from a black body are proportional to

 T*

399.

Damping of the Ballistic galvanometer is made small to

 get first deflection large

400.

The pulsating torque exerted by steam locomotives causes which of the following?

 Jolting and skidding

401.

The capacitance, in force-current analogy, is analogous to
 mass 

402.

Which of the following statements is/are true ________
 Voltage regulation for short transmission line = (Vs - Vr) / Vr 

403.

The most modern method for food processing is ________

 Induction heating.

404.

A 230 V, 50 Hz, 4 pole single phase induction motor is rotating in the clockwise ( forward ) direction at a speed of 1425 rpm. If the rotor resistance at standstill is 7.8 degree. Then the effective rotor resistance in the backward branch of the equivalent circuit will be ??

 4 degree

405.

Which of the following high resistance materials has the highest operating temperature ?

 kanthal

406.

Between a hollow and solid metal sphere, charge reside ?
 On outer surface in both. 

407.

Electric pressure is also called
 voltage 

408.

The viscous friction co-efficient, in force-voltage analogy, is analogous to
 resistance 

409.

In order to increase the damping of a badly underdamped system which of following compensators may be used ?

 Phase-lead

410.

Which of the following affect greatly the resistivity of electrical conductors ?

 Composition

411.

When the initial conditions of a system are specified to be zero it implies that the system is

 at rest but stores energy

412.

The resistivity of a metal is a function of temperature because
 the amplitude of vibration of the atoms varies with temperature 

413.

________ has a low relative permeability and is used principally in field frames when cost is of primary importance and extra weight is not objectionable.
 Cast iron 

414.

In an 8085 microprocessor

 data bus and address bus are multiplexed

415.

In a low power factor wattmeter the compensating coil is connected
 in series with pressure coil 

416.

Bundled conductors in EHV transmission lines ______?
 decrease inducatance 

417.

When the two coil sides forming a coil are spaced exactly one pole pitch apart they are said to be of
 full pitch