📘 Electrical Drives & Control – Polytechnic PYQ Collection (2014-2019)

📘 Electrical Drives & Control – Polytechnic PYQ Collection (2014-2019)

This document contains previous year question papers for the subject Electrical Drives & Control (EDC) from April 2014 to April 2019, compiled by Mannar Mannan V, Lecturer/EEE – GPTC Nagercoil.

✅ Unit-wise questions
✅ 1-mark, 2-mark, 3-mark & 14-mark questions
✅ DC & AC Machines, Transformers, Stepper/Servo Motors
✅ VFD, Power Supplies, SMPS, PLC & Control Elements
✅ Useful for Tamil Nadu Polytechnic Diploma – EEE students

🔎 Best for:
• TN DOTE Polytechnic Diploma
• EEE 2nd year / Electrical students
• Exam preparation & unit revision
• Board exam question pattern practice

📂 Units Covered:
1️⃣ DC Circuits & DC Machines
2️⃣ AC Circuits & AC Machines
3️⃣ Special Machines & Drives
4️⃣ Power Supplies & Electrical Safety
5️⃣ Logic Gates, PLC & Display Devices

1. Electrical Drives and Control
Apr 2014 to Apr 2019
By Mannar Mannan V, Lect./EEE
119 - GPTC, Nagercoil
Previous Year Questions

2. UNIT - I
DC Circuits and DC Machines
1 State Ohm's law [ Apr 2019 ] [ Apr 2018 ] [ Apr 2017 ]
2 What is frequency? [ Apr 2019 ]
3 What is Power? [ Apr 2019 ] [ Oct 2018 ]
4 State Faradays law's of electromagnetic induction. [ Apr 2019 ] [ Oct 2018 ]
5 What is MMF and Reluctance? [ Apr 2019 ] [ Apr 2017 ]
6
What is the total resistance of two 5 ohm resistors
connected in series and in parallel?
[ Apr 2018 ]
7 State Kirchoff's voltage law. [ Oct 2018 ]
8 Mention any two applications of DC Series motor. [ Oct 2018 ]
9 What is Power Factor? [ Oct 2018 ]
10 What is time period? [ Apr 2017 ]
11
Derive an expression for the equivalent resistance
when two resistors are connected in parallel.
[ Apr 2017 ]
3 Mark Questions
UNIT - II
AC Circuits and AC Machines
1 Name the starters used in 3 phase induction motor. [ Apr 2019 ]
2 Define the efficiency of transformer with an equation. [ Apr 2019 ] [ Apr 2017 ]
3 What is the necessity of starters? [ Apr 2019 ] [ Apr 2018 ]
4 What is the emf equation of a transformer? [ Apr 2018 ]
5 State the losses in transformer. [ Apr 2018 ] [ Oct 2018 ] [ Apr 2017 ]
6 What is the relation between line voltage and phase [ Apr 2018 ] [ Oct 2018 ]
7
State the methods of speed control of three phase
induction motor
[ Apr 2018 ] [ Oct 2018 ]
8
Explain pole changing method of speed control in a 3
phase induction motor.
[ Oct 2018 ]
9 Mention the types of alternator. [ Apr 2017 ]
10
Compare 3 phase squirrel cage and slip ring induction
motor.
[ Apr 2017 ]

3. UNIT - III
Special Machines and Drives
1 Expand PMDC. [ Apr 2014 ]
2 What is multimotor drive? [ Apr 2014 ]
3 What is half stepping? [ Apr 2014 ] [ Oct 2014 ]
4 What is group drive? [ Oct 2014 ] [ Oct 2015 ]
5 Define step angle. [ Apr 2015 ]
6 Mention the three types of electric drives. [ Apr 2015 ]
7 What is stepper motor? [ Oct 2015 ]
8 What is servo motor? [ Apr 2016 ] [ Oct 2016 ] [ Apr 2017 ]
9 Write the switching sequence of stepper motor. [ Oct 2016 ]
10 Mention the type of rectifier. [ Apr 2016 ]
11 Draw the VFD Block diagram. [ Apr 2017 ]
UNIT - IV
Power Supplies, Control Elements and Electrical Safety
1 Anyone precaution to prevent electric shock.
2 Define electric shock.
3 What is a diode?
4 Write the necessity of fuse.
5 What is CB?
6 Expand MCB.
7 Expand MCCB.
8 Expand ELCB.
9 Expand SMPS.
10 What is fuse and what is contactor?
11 Draw the symbol of PN junction diode.
12 Define Inverter and Rectifier.
13 Define earthing.
14 Explain voltage regulator and its types.
15 Mention the types of fuses.
16 Write the necessity of filters in rectifiers.
UNIT - V
1 Draw the symbol for NOR Gate [ Apr 2014 ]
2 Draw the symbol for NAND Gate [ Oct 2014 ] [ Apr 2017 ]
3 Draw the symbol for NO and NC Contacts [ Oct 2014 ] [ Apr 2016 ] [ Oct 2016 ]
4 Draw the symbol for LED. [ Oct 2015 ] [ Apr 2016 ]
5 List the Universal Logic gates [ Apr 2014 ] [ Oct 2014 ]
6 List the basic logic gates. [ Oct 2015 ] [ Oct 2016 ] [ Apr 2016 ]
7 Mention any three advantages of LCD. [ Apr 2015 ]
8 Mention any three applications of PLC. [ Apr 2015 ]
9 Explain positive logic and negative logic. [ Apr 2015 ]
10 Expand PLC. [ Apr 2014 ]
11 Write the components of PLC. [ Apr 2016 ]

4. UNIT - I
DC Circuits and DC Machines
1 Explain the principle of operation of a DC Motor. [ Apr 2019 ] [ Apr 2018 ]
2 Problem [ Apr 2019 ] [ Apr 2018 ] [ Oct 2018 ]
3 Explain the constructional details of DC Generator
with neat diagram. (14m)
[ Oct 2018 ]
4 Explain the construction and working of 3 point
starter. (14m)
[ Oct 2018 ] [ Oct 2017 ]
5 Explain the construction and working of 4 point
starter. (14m)
[ Apr 2017 ]
UNIT - II
AC Circuits and AC Machines
1 Define the relationship between line current and
phase current in delta connected system. (14m)
[ Apr 2019 ] [ Apr 2017 ]
2 Explain the construction and operation of DOL Starter. [ Apr 2019 ] [ Apr 2018 ] [ Apr 2017 ]
3 Explain the working of squirrel cage three phase in-
duction motor. (14m)
[ Apr 2018 ]
4 Explain the construction and principle of operation of
Alternator. (14m)
[ Oct 2018 ]
5 Explain the construction and working of single phase
capacitor start induction motor. (14m)
[ Oct 2018 ]
6 Explain the construction and principle of operation of
transformer. (14m)
[ Apr 2017 ] [ Oct 2017 ]
7 Explain the construction and operation of Star-Delta
Starter. (14m)
[ Oct 2017 ]
UNIT - III
Special Machines and Drives
1 Draw and Explain the block diagram of variable fre-
quency drive (VFD). (7m)
[ Apr 2014 ] [ Oct 2014 ] [ Apr 2015 ]
[ Apr 2016 ]
2 Explain the working principle of Stepper motor. (7m or
14m)
[ Oct 2014 ] [ Oct 2016 ] [ Apr 2017 ]
[ Apr 2019 ]
3 Explain the working principle of PMDC motor. (7m) [ Apr 2014 ] [ Oct 2017 ]
4 Explain Brushless Servo motor. (7m) [ Apr 2014 ] [ Oct 2014 ]
5 Explain the working principle of AC and DC Servo
motor. (14m)
[ Oct 2015 ] [ Apr 2015 ]
6 Explain the working principle of Single Stepping Step-
per motor (7m or 14m)
[ Oct 2017 ] [ Oct 2018 ]
7 Explain the working principle of Half Stepping Stepper
motor (7m or 14m)
[ Apr 2016 ] [ Oct 2018 ]
8 Explain Industrial Drives. (14m) [ Oct 2015 ] [ Oct 2018 ]
9 Explain the construction and applicatons of PM Servo
motor.
[ Apr 2018 ]
7 and 14 Mark Questions

5. UNIT - IV
Power Supplies, Control Elements and Electrical Safety
1 Explain the working of a Halfwave Rectifier.
[ Apr 2016 ] [ Apr 2018 ] [ Oct 2014 ]
[ Oct 2016 ] [ Oct 2018 ]
2 Explain the working of a Fullwave Rectifier. [ Apr 2014 ] [ Apr 2015 ] [ Oct 2015 ]
[ Oct 2017 ] [ Apr 2019 ]
3 Write the first aid for electrical shock and their pre-
venting measures.
[ Apr 2014 ] [ Apr 2015 ] [ Apr 2016 ]
[ Apr 2017 ]
4 Why earthing is important? write the causes and pre-
vention of accidents.
[ Oct 2014 ] [ Apr 2015 ] [ Apr 2019 ]
5 Explain about PN Junction diode. [ Oct 2014 ] [ Apr 2016 ] [ Apr 2017 ]
6 Explain the working of a inductive proximity sensor. [ Oct 2014 ] [ Apr 2016 ] [ Apr 2017 ]
7 Explain the working of a photo electric sensor. [ Apr 2014 ]
8 Explain the working of a Bridge rectifier. [ Apr 2018 ]
9 Explain the working of a Earth Leakage Circuit
Breaker.
[ Apr 2017 ]
10 Explain filter. Explain the need of filter for a DC
rectifier.
[ Oct 2016 ]
UNIT - V
Display Devices, Logic gates and PLC
1 Explain PLC with neat block diagram. [ Oct 2014 ] [ Oct 2015 ] [ Oct 2017 ]
[ Apr 2015 ] [ Apr 2017 ] [ Apr 2018 ]
[ Apr 2019 ]
2 Write the boolean expressions, logic symbols and
truthtables for all logic gates and explain.
[ Apr 2015 ] [ Apr 2016 ] [ Oct 2015 ]
[ Oct 2016 ] [ Oct 2017 ] [ Oct 2018 ]
3 What is positive logic and negative logic ? [ Oct 2014 ] [ Apr 2014 ]
4 Write the applications of PLC. [ Oct 2016 ] [ Apr 2016 ]
5 Write short notes on LED. [ Apr 2017 ] [ Apr 2019 ]
6 Explain the working of 7 Segment Display LED. [ Apr 2014 ]
7 Write the advandages and disadvantages of LCD. [ Apr 2016 ]
8 Describe how NAND gate is used as Universal logic
gates.
[ Apr 2017 ]
9 Explain the types of PLC Scan. [ Oct 2018 ]

6. Problems