Industrial drives and control Sample Question Paper I Scheme MSBTE Electrical Engineering Group

Q.1)Attempt any Five of the following.
(10 Marks)

a) Draw block diagram of the Basic elements of electric drives.
b) State the need of electric drives.
c) State the types of SCR controlled drives
d) Draw circuit diagram of half wave converter.
e) List various methods of control the speed of AC drive.
f) Draw a block diagram of microprocessor based DC motor controller .
g) State the function of microprocessor in drives.

Q.2)Attempt any Three of the following.
(12 Marks)

a) Describe the four quadrant operation of induction motor with speed torque
characteristics.
b) Compare semi converter drives and full converter drives on the basis of 1) Quadrant
operation 2) Regenerative braking 3) Power flow 4) harmonic contents
c) Draw and describe class C chopper drive.
d) Draw the block diagram of constant V to F control method and describe it’s working

Q.3) Attempt any Three of the following.
(12 Marks)

a) List the duty class of motor and describe continuous duty class.
b) Draw the circuit a three phase semiconverter drive. State the equation of average
armature voltage.
c) Draw and describe class D chopper drive
d) List no of stages involved in paper mill. Which type of motor/drives used at each
stage?

Q.4) Attempt any Three of the following.
(12 Marks)

a) Draw and describe the operation of chopper circuit used for reversible drive
b) State the stages involved in textile mills and type of drives used for it.
c) Describe the working of variable frequency control using square wave inverter.
d) Draw labeled block diagram of phase lock loop (PLL) control DC motor drive. State
function of each block.
e) Describe role of microprocessor for speed control of DC motor with neat diagram .

Q.5) Attempt any Two of the following.
(12 Marks)

a) Draw circuit diagram of three phase dual converter using SCR and describe working
principle with wave forms
b) Draw and describe four quadrant chopper drive.
c) State the rating and specification of stepper motor.

Q.6) Attempt any Two of the following.
(12 Marks)

a) A semi converter operated from single phase 230 volt, 50 Hz supply drives a 10HP,
200 volt, 1500rpm, separately excited DC motor. The rated armature current is 40A,
the motor parameters Ra=05ohm, La=10mH. KaØ constant =0.2V/rpm. Find out the
following parameters α = 30 0 i) average armature voltage, ii) back emf of motor iii)
speed of motor iv) motor torque.
b) Classify the chopper based on the output voltage and quadrant of operation. Describe
class A chopper with circuit diagram
c) Describe the stator voltage control method of three phase induction motor with circuit diagram