🎓 Education: B.Tech, [College Name]
📅 Year of Graduation: 2022
💼 Work Experience: Havells – Induction Motor Manufacturing Unit
🗓️ Gap Justification: Worked at Havells post-B.Tech before appearing for PSUs
👷 Work Experience-Related Questions:
- What is your college and B.Tech pass-out year?
→ Answered: 2022 - Why the gap after graduation?
→ Response: I was working at Havells in the Induction Motor Division. - What kind of products does Havells manufacture?
→ Switchgear, protection equipment, lighting products, and both single-phase and three-phase induction motors. - What was your role at Havells?
→ Assigned to the induction motor manufacturing plant. - What are the typical ratings of induction motors manufactured by Havells?
→ Explained standard ratings based on their product catalog.
⚙️ Induction Motor & Electrical Machines:
- Which device is used to sense the temperature of an induction motor?
→ Thermistor, RTD (Resistance Temperature Detector), or Thermocouple depending on application. - What protection is used for large-rating induction motors?
→ Overload relay, temperature sensor, earth fault protection, differential protection, etc. - Applications of single-phase induction motor?
→ Ceiling fans, refrigerators, washing machines, air conditioners, etc. - Working principle of a single-phase induction motor?
→ Based on the principle of a pulsating magnetic field; needs auxiliary means to start. - Are single-phase induction motors self-starting?
→ No, due to the absence of rotating magnetic field at startup. - How do we start a single-phase induction motor?
→ By using methods like split-phase, capacitor-start, or shaded pole technique. - How is a three-phase induction motor self-starting?
→ It produces a rotating magnetic field, which induces current in the rotor, enabling it to start on its own. - What device is used in a fan regulator?
→ TRIAC or electronic dimmer circuits for speed control.
🔋 Power Systems & Machines:
- What are the conditions required to synchronize a synchronous generator to a grid?
→ Voltage, frequency, phase sequence, and phase angle must match. - What should be the resistance of an ideal conductor?
→ Zero ohms. - What should be the resistance of an ideal insulator?
→ Infinite (or very high) resistance. - What is superconductivity?
→ A phenomenon where certain materials exhibit zero electrical resistance below a critical temperature. - If we reduce the number of turns in the primary winding of a transformer, what happens to the secondary voltage?
→ It increases (as per the transformer equation: V₁/V₂ = N₁/N₂).
🧮 Circuit Theory & Concepts:
- In a series RLC circuit with DC voltage, draw voltage across R, L, and C with respect to time.
→ Explained transient response:- Resistor: Instant voltage
- Inductor: Gradual rise
- Capacitor: Charging curve
- An equilateral triangular core has supply in all three arms with a rotor placed in the center — will it rotate?
→ Yes, if the setup creates a rotating magnetic field like in a three-phase system. - What is a double cage rotor induction motor?
→ A special rotor design with two cages:- Outer cage: High resistance (better starting torque)
- Inner cage: Low resistance (better efficiency at full load)
- Why is the starting current of an induction motor and DC motor high?
→ Because at the start, there is no back EMF, and the impedance is low. - Why is back EMF zero at starting?
→ Because back EMF is proportional to speed, and at start, speed is zero.
✅ Final Thoughts:
- Panel Style: Technical, focused on fundamentals and practical exposure
- Key Areas Covered: Induction motors, protection systems, electrical machines, circuit theory
- Pro Tip: Link your work experience smartly with concepts. Prepare to explain both industrial applications and theoretical foundations.
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