A separately excited d.c. motor is fed from a chopper operating at 500 Hz with a duty cycle of 50% and is drawing an average current of 10A from a 200V d.c. source. A free wheeling diode is connected across it. The motor has negligible armature resistance; a field inductance of 50mH and a torque constant of 0.5 N-m/A. determine the minimum and maximum motor current, motor back e.m.f. and the mechanical torque developed.

A 3-input 2-output priority encoder has the following truth table where X’s indicate don’t care conditions. Realize the logic using NAND gates and inverters

Compute the amplitude of the fundamental component of the waveform given in figure

A system governed by the differential equation  is initially at rest. Determine the value of y at t=0.1s using the trapezoidal rule of integration with a step size of 0.05s

Introduction of integral action in the forward path of a unity feedback system results in a

Two identical coils negligible resistance when connected in series across a 200V, 50Hz source draws, a current of 10A. When the terminals of one of the coils are reversed, then current drawn is 8A. The coefficient of coupling between the two coils is

For the circuit shown in Fig, the wattmeter reading will be ______ W and the power dissipated in the load is ______ W

The primary current in a current transformer is dictated by

In the circuit shown in figure, for measuring resistance ‘R’ if the ammeter indicates 1A and the voltmeter indicates 100V, then the value of R is_____ Ohms and the error in measurement using the ratio V/I is _____ %  

In the capacitor divider arrangement shown in Figure, for measurement of high voltages, the minimum resistance of the voltmeter for 1% error is __________ Ohms and the voltage reading will be __________ V.

An ideal voltage source will charge an ideal capacity

A single-phase bridge inverter is fed from a 200V d.c. supply and is operated at 50Hz. It is connected to a load having a resistance of 20 ohms and an inductance of 0.2H. Draw the load current waveform in the steady indicating the peak values.

A practical current source is usually represented by

For the differential amplifier circuit shown in Figure, determine the differential gain, the common-mode gain and the common-mode rejection ratio.

In a LVDT, the two secondary voltages

For the circuit shown in figure. The Norton equivalent source current value is _________ A and its resistance is _________ Ohms

In the circuit shown in figure. eg(t)=2.5t volts. What are the values of i(t) and VL(t) at t=4 seconds?

Energy stored in a capacitor over a cycle, when excited by an a.c. source is

A 0–1000 micro ampere microammeter guaranteed to be 0.1% accurate needs to be calibrated using a 1.0 V d.c. potentiometer. Draw the circuit diagram and find the value of the standard resistance used and the least count of the potentiometer.

A 100MVA, 11kV, 3-phase, 50Hz, 8-pole synchronous generator has an inertia constant H equal to 4 seconds. The stored energy in the rotor of the generator at synchronous speed will be  

Find the Thevenin equivalent about AB for the circuit shown in figure

For the two port network shown in figure, the admittance matrix is . Then Find  
\(Y_{11} + Y_{12} + Y_{22} + Y_{21} = ?\)

The system represented by the transfer function  has _______ pole(s) in the right-half s-plane.  

The use of high-speed circuit breakers

For a fault at the terminals of a synchronous generator, the fault current is maximum for a

A square matrix is called singular, if its

Determine whether the system given by the block diagram of figure, is stable ( Yes=1, No=0)

A 10V battery with an internal resistance of 1Ω is connected across a nonlinear load whose V-I characteristic is given by . The current delivered by the battery is __________ A

Gauss-Seidel iterative method can be used for solving a set of

A synchronous motor is receiving 50% of the power. It is capable of receiving from an infinite bus. If the load on the motor is suddenly reduced to 80% of the previous value, swing of the motor around its new equilibrium position.

A unity feedback system with the open loop transfer function  has gain margin of…. dB

In a microprocessor, the address of the next instruction to be executed, is stored in

The synchronous reactance of a 200 MVA, 10kV, 3-phase, 50Hz generator is 1.0p.u. at its own base. Its p.u. reactance at 100MVA, 20 kV base will be……

The values of E and I for the circuit shown in figure, are_________V and _________A. Then E+I= ?

The system shown in figure feeds two loads-        

(a) a factory load of 15 MVA consisting of induction motors and (b) a domestic load of 10MW at 0.8p.f. lagging at 6kV. If the induction motors are rated at 6 kV and take 5 times their rated current at zero p.f. at starting, calculate the dip in voltage at the domestic load bus bar when all the induction motors are started at the same time.

The computer program which converts statements written in high level language to object code is known as

The voltage and current waveforms for an element are shown in figure. The circuit element is _________And its value is

An infinitely long straight wire carries 1000A of current and in the vicinity there is a circular conducting loop of 100mm diameter with the center of the loop 1m away from the straight conductor. Both the wire and the loop are coplanar. Determine the magnitude and direction of current in the loop that produces a zero flux density at its center.

In a uniform electric field, field lines and equipotentials

Determine the transfer function of the system having the following state variable representation:         

Express the given matrix A as a product of two triangular matrices, L and U, where the diagonal elements of the lower triangular matrix L are unity and U is an upper triangular matriX

In a dual converter, the circulating current

An SCR is connected in series with a 300V ac supply and a 300 ohms load resistor. Calculate for a firing angle of 45°

1. The reading of a moving coil ammeter connected in series with the load and
2. The reading on a moving iron voltmeter connected across the SCR

A square coil of turns and 10cm side is moved through a steady magnetic field of  at a constant velocity of 2m/sec with its plane perpendicular to the field as shown in figure. Plot the variation of induced e.m.f as the coil moves along the field.

The capacitance of the arrangement shown in figure is ________ pF

The range of address for which the memory chip shown in figure, will be selected is_________ to_________

The capacitance of an isolated sphere of radius 10cm in air is equal to ________ pF

Reactance relay is normally preferred for protection against

Determine the electric field intensity at the point p for the arrangement shown in figure above

If a diode is connected in anti-parallel with a thyristor, then

A 5kW, 200V DC shunt motor has an armature resistance of 1 ohm and shunt field resistance of 100 ohms. At no-load, the motor draws 6A from a 200V supply and runs at 1000rpm. The rotational loss of the machine is… W and the no load torque is… N-m

A major advantage of active filters is that they can be realized without using

A single-phase alternator has a synchronous reactance of 2 ohms and negligible resistance. If it supplies 10A to a purely capacitive load at 200V, then generated e.m.f will be… V and the regulation will be…%

A 200V, 10kW lap-wound DC generator has 10 poles and 500 conductors on its armature. If the pole face covers 80% of the pole pitch, the pole face conductors required to fully compensate for armature reaction will be…. conductors/pole.

A first order system is initially at rest and excited by a step input at time t=0. Its output becomes 1.1V is in 4 seconds and eventually reacts a steady state value of 2V. Determine its time constant

A differentiator has transfer function whose

The field coil of a two-pole DC series motor is made up of two identical sections. In one case (i) of two sections of the field coil are connected in series, and in another case (ii) the two sections are connected in parallel. If the motor takes the rated current in both the cases, then torque (i): torque (ii) is ….. and speed (i): speed (ii) is ….. (Neglect the effect of magnetic saturation)

A dynamometer type wattmeter responds to the

The low voltage winding of a 400/230V, 1-phase, 50Hz transformer is to be connected to a 25Hz supply, the supply voltage should be

The circuit shown in figure, acts as a… and for the given inputs, its output voltage is… V         

For an input signal 4sin10t, the voltage across the resistance R in the circuit shown in figure, is … V

At 50% of full load, the armature current drawn by a DC shunt motor is 40A when connected to a 200V DC mains. By decreasing the field flux, its speed is raised by 20% this also causes a 10% increase in load torque. Calculate the percentage change in field current. The armature resistance including the brushes is 1 Ohm. Neglect saturation and armature reaction.

A transfer instrument employed in the standardization of a polar type AC potentiometer is

A voltage v=400sin(314.16t) is applied to a 1-phase transformer on no-load. If the no load current of the transformer is 2sin(314.16t-85°), then magnetization branch impedance will be approximately equal to

Determine the frequency of oscillation of the circuit shown in figure. Assume the op-amp to be ideal

A 3-phase transformer bank consists of three identical 2300/230V, 15 kVA single-phase transformers connect in delta/delta. The bank supplies a 20 kVA, unity p.f. 3-phase load. If one of the single-phase transformer develops a fault, and is removed, the load carried by each of the two transformers now operating in open delta will be… kVA.

Given figure shows a magnetic circuit formed by an ideal core material. Determine the magnetic flux density in the air gap.

If an induction machine is run at above synchronous speed, it acts as

A 3-phase, 20kW, 400V, 1470rpm, 50Hz squirrel cage induction motor develops a torque of 100 N-m at a speed of 1400rpm. If the motor is connected to a 30Hz supply, for keeping the same air-gap flux, then supply voltage should be… V and for the same load torque, the new speed will be…. Rpm

A 50kVA, 400V, 3-phase, 50Hz squirrel cage induction motor has full load slip of 5%. Its standstill impedance is 0.866 ohms/phase. It is started using a tapped autotransformer. It the maximum allowable supply current at the time of starting is 100A, then calculate the tap position and the ratio of starting torque to full load torque

Bundled conductors are employed to improve the

The velocity of propagation of electromagnetic wave on an underground cable with relative permittivity of 3 will be __________

Two power systems A and B each having a regulation (R) of 0.05 p.u. on their respectively capacity bases and a stiffness (damping coefficient) of 0.75 p.u. are connected through a tie-line, initially carrying no power. The capacity of system A is 2000 MW and that of system B is 3000MW. If there is an increase in load of 200MW in system A, what is the change in the steady-state frequency and power transfer?

A factory draws 100kW at 0.7p.f lagging from a 3-phase, 11 kV supply. It is desired to raise the p.f. to 0.95 lagging using series capacitors. Calculate the rating of the capacitor required in μF .