Preston UniversityCourse Code: BT-3219Course Title: Industrial MachinesProgram: B-Tech. (Pass) Electrical TechnologySemester: Spring 2015

Note: This is a three hour examination and consists of review questions only. You may attempt not more than seven questions.

Question 1 A ferromagnetic core is shown in the following fig. Assuming the following o = 4X10-7 H/Mr= 2 5 0 0 i = 1A Calculate the flux produced in the core.

Question 2For the power system shown in the following figure, calculate; i. Load voltage ii. Line losses

Question 3 a) Draw Power Triangle. Explain different types of power. b) What is open delta connection of two transformers? Why does the output power decrease in case of open delta connection?

Question 4 Write short notes on any four of the following power electronic components: i. SCR ii. DIAC iii. TRIAC iv. DC-DC Chopper

Question 5A three phase, Y-connected, 50Hz, two pole synchronous machine has a stator with 2000 turns of wire per - phase. What rotor flux would be required to produce a terminal (line to line) voltage of 6KV?

Question 6 At a location in Europe, it is necessary to supply 300 KW of 60Hz power. The only power sources available operate at 50Hz. It is decided to generate the power by means of a motor-generator set consisting of a synchronous motor driving a synchronous generator. How many poles should each of the two machines have in order to convert 50Hz power to 60Hz power?

Question 7 For the power system shown in the following figure, calculate the line current:

Question 8 Explain different types of DC Motors with the help of circuit diagram and characteristic curves.

Question 9 Write note on the equivalent circuit of induction motor and explain that the emf induced on rotor is dependent on speed of rotation.

Question 10Write short notes on any TWO of the following: i. PMDC Motor ii. Stepper Motor

Question 11 A 50HP, 250V, 1200 T/min dc shunt motor with compensating windings as shown in the following figure. The no load speed of 1200 r/min. There are 1200 turns per pole on the shunt field winding. i. Find the speed of this motor when its input current is 100A. ii. Find the induced torque when the load current is 100A.