Code No: 410257 IV-B.Tech. I-Semester Supplementary Examinations, May-2004 POWER SEMI CONDUCTOR DRIVES (Electrical and Electronics Engineering) Time: 3 Hours Max. Marks: 70 Answer any FIVE questions All questions carry equal marks --1.a) Explain how four-quadrant operation is achieved by dual converters each of 3 full wave configuration for d.c. separately excited motor. b) Distinguish between circulating current and non-circulating current mode of operation. With a neat diagram, explain the operation of a dc drive in all four quadrants when fed by a single phase dual converter with necessary waveforms and characteristics.
3.a)
List the advantages offered by dc chopper drives over line-commutated converter controlled dc drives. A dc chopper controls the speed of dc series motor. The armature resistance Ra = 0.04, field circuit resistance Rf = 0.06, and back emf constant Kv = 35 mV/rad/s. The dc input voltage of the chopper Vs=600v. If it is required to maintain a constant developed torque of Td = 547N-m, plot the motor speed against the duty cycle K of the chopper.
4.a) b)
Using 3 phase solid state AC Voltage Controllers explain clearly how it is possible to achieve 4 quadrant operation of 3 phase Induction motors. Draw a closed loop block schematic diagram for the above speed control technique. Mention the merits of the above method of speed control.
uW
b)
or ld
2.
Compare CSI and VSI drives. Show that a variable frequency Induction motor drive develops at all frequencies the same torque for a given slip-speed when operating at constant flux.
6.a)
What are the assumptions made in the static resistance control of wound rotor induction motors? Draw the speed-torque characteristics of a rotor resistance controlled induction motor and explain the effect of rotor resistance variation. Why rotor resistance control is preferred in low power crane drives?
nt
5.a) b)
b)
Aj
c)
7.
Explain the operation of a synchronous motor fed from an adjustable frequency current source, with circuit diagram and characteristic curves.
8.
Explain, under what conditions the load commutation for CSI can be applied and discuss the operation with modified CSI . Give few advantages. $$$
b) Explain the principle of single tuned capacitance coupled amplifiers. 3.a) Classify various commutation techniques. Also explain class A commutation.
chimney attached to the boiler? Explain how will you estimate its concentration · in this flue gas? 5. Describe the removal of sulphurdioxide by dry process using ...
... band factor 16, one start bit, one stop bit, even · parity enable. Further transmit a message 'HAPPY NEW YEAR' in ASCII coded · form to a modem. ###. OR.
(figure.1). (c) Obtain Thevenin's equivalent circuit for the network below figure 2. 1 of 3 ... (a) Obtain open circuit and short circuit parameters. Obtain relation ...
Show the reaction mechanisms of the following reactions. (a) Gatterman reaction. ... How will you determine the configuration of glucose with the help of Fischer's method? 7. (a) What ... Explain the theory of colour and constitution? *****. 1 of 1.
Maximize the following problem using Simplex Method. Z = 10x + y + ... 10; x1, x2 ⥠0. 8. Write short notes on the following: (a) Kuhn-Rucker conditions. 1 of 2 ...
Explain the Remote procedure call in detail. 3. Explain distributed Deadlock Detection and prevention methods. 4. Explain the following processor Allocation ...
(b) A single phase fully controlled bridge converter is supplied at 230V, 50Hz, ... Explain the operation of single phase A.C. voltage controller with Resistive and.
What is a rocket, what are the various types and applications? 6. How the satellites are put in to the orbit and what are the requirements of the propulsion system ...
7. a) What is creep? Explain the effect of temperature and load on creep curves. b) Explain the various atomic mechanisms involved in deformation at high.
4.a) What are the various types of rolling mills and discuss their relative advantages ... b) Draw the pressure distribution plot along arc of contact and explain its.
(c) How do you decrease the partical pressure of a component in a cracker. 4. Explain with a flow sheet the working of petrochemical complex. 5. (a) Butane is ...
Present a program schema for a FIFO branch and bound search for a Least â Cost · answer node. 8. Explain in detail how the technique of backtracking can be ...
(a) What are the industrial applications of TIMER CKTS? (b) What are the electronic welding controls used in resistance welding? (c) What are advantages of ...
b) Prove the independent laws for the elements of a lattive. 4. Using Warshall's algorithm, compute the adjacency matrix of the transitive · closure of the digraph.
Functions with half wave symmetry have only odd harmonics. 3. (a) Determine ... (a) State and prove the convolution and scale change properties in z transform.
to overcome this problem. Discuss. 7. (a) Distinguish between Mealy and Moore machines. (b) Convert the following Mealy machine into a corresponding Moore ...
