BTSC Work Inspector Study Material
Comprehensive Electrician Trade Guide for Bihar Technical Service Commission (Hinglish)
Start LearningChapter 1: Electrical Safety
Safety sabse pehle aati hai. Electrical work mein choti si galti bhi jaanlewa ho sakti hai.
1. Electric Shock
Jab current human body se pass hokar ground mein jaata hai, use Electric Shock kehte hain. Intensity depends on Current Magnitude and Duration.
- Primary Shock: Dangerous current passing directly through the heart or nervous system.
- Secondary Shock: Mild shock that scares you, causing you to fall (e.g., from a ladder).
2. Step & Touch Voltage
- Step Voltage: Difference of potential between two feet when walking on faulty ground.
- Touch Voltage: Difference between hand touching a faulty structure and feet on the ground.
3. Safety Systems
Permit to Work (PTW)
High Voltage line par kaam karne se pehle written permission lena zaroori hai. Isse confirm hota hai ki line OFF hai aur Grounded hai.
Housekeeping (5S)
Workplace saaf hona chahiye. (Sort, Set in Order, Shine, Standardize, Sustain). Wires bikhre nahi hone chahiye.
4. Fire Safety
Electrical Fire (Class C) ke liye paani ka use kabhi na karein. Humesha CO2 ya Dry Powder Extinguisher use karein.
Chapter 2: Tools & Basics
1. Basic Electrical Concepts
Ohm’s Law (V = IR)
At constant temperature, Current is directly proportional to Voltage.
Series vs Parallel
- Series: Ek rasta hota hai. Ek bulb kharab hua to sab band. (Example: Diwali Lights).
- Parallel: Alag-alag raste hote hain. Ek bulb kharab hua to baaki chalte rahenge. (Example: Ghar ki Wiring).
AC vs DC Supply
- AC (Alternating Current): Direction badalta rehta hai. Transformers use kar sakte hain.
- DC (Direct Current): Ek hi direction mein behta hai. Batteries aur Electronics mein use hota hai.
2. Important Tools
Check karta hai ki R-Y-B supply sahi order mein hai ya nahi (3-Phase motors ke liye zaroori).
Chalti hui wire mein bina connection kaate Current measure karne ke kaam aata hai.
Cable ki insulation check karne ke liye use hota hai (High Resistance measure karta hai).
Chapter 3: Wiring
1. Wiring Basics
Point Wiring: Switch se lekar Bulb/Fan tak ki wiring ko Point Wiring kehte hain.
Neutral: Current wapas le jaane ka rasta hai (Circuit complete karta hai).
Earth (Ground): Safety ke liye hai. Agar body mein current aa jaye, to Earth wire usse zameen mein bhej degi taaki insaan ko shock na lage.
2. Accessories & Switches
- SPST (Single Pole Single Throw): Normal on/off switch.
- SPDT (Single Pole Double Throw): Staircase wiring (Jeene ki wiring) mein use hota hai jahan ek bulb do jagah se control hota hai.
- Junction Box: Jahan wires ko join kiya jata hai ya direction change hoti hai.
3. Fault Finding
- Open Circuit: Wire toot gayi hai -> Current flow nahi hoga.
- Short Circuit: Phase aur Neutral jud gaye -> Bahut zyada current flow hoga aur spark hoga.
- Leakage Current: Insulation weak hone par current walls ya body mein aa jata hai.
Joints in Wiring:
- Britania Joint: Overhead lines mein tensile strength badhane ke liye.
- Rat Tail / Pig Tail Joint: Junction box mein use hota hai jahan wire par khinchav (stress) nahi hota.
Chapter 4: Electrical Effects
1. Heating Effect
Current flow hone par wire garm hoti hai ($H \propto I^2$). Iska use Heater, Geyser, aur Fuse mein hota hai.
Fuse: Ek baar ud gaya to badalna padta hai (wire pighal jaati hai).
MCB: Trip hone par wapas Utha (ON) kar sakte hain. Ye magnetic aur thermal dono effect par kaam karta hai.
2. Magnetic Effect
Electromagnet: Soft Iron core par wire lapet kar current dene par wo magnet ban jaata hai. (Use: Electric Bell, Relays).
Lenz’s Law (Most Important)
Definition: The direction of induced EMF is such that it always opposes the cause producing it.
“Jis thaali mein khaya, usi mein ched kiya”
Explanation:
Jab hum kisi Magnet ko Coil ke paas laate hain, to Coil mein current paida hota hai. Lekin ye naya paida hua current apna khud ka magnetic field bana leta hai jo ussi Magnet ko paas aane se rokta hai.
Yani jis Magnet ke movement ne use paida kiya, wo current usi movement ka virodh (oppose) karta hai.
3. Chemical Effect (Battery)
- Primary Cell: Use and throw (Remote battery).
- Secondary Cell: Rechargeable (Inverter/Car battery).
Maintenance Tip: Lead Acid battery mein pani ka level (Electrolyte) samay par check karein. Terminal par grease lagayein taaki corrosion na ho.
Chapter 5: Machines
1. DC Machines
Works on the principle of Electromagnetic Induction.
- Generator: Mechanical Energy → Electrical Energy (Fleming’s Right Hand Rule).
- Motor: Electrical Energy → Mechanical Energy (Fleming’s Left Hand Rule).
2. Transformer
Static device jo Voltage level change karta hai bina Frequency change kiye.
- Step-Up: Voltage badhata hai (Transmission lines).
- Step-Down: Voltage ghataata hai (Ghar ke paas wala distribution transformer).
3. Induction Motor (3-Phase)
Industry ka “Workhorse”. Simple aur Rugged hoti hai.
Starters:
- DOL (Direct On Line): Upto 5HP motors. Direct supply deta hai.
- Star-Delta Starter: High power motors (>5HP) ke liye.
About the Author
Expert in ITI Electrician trade and technical education with years of experience in simplifying complex electrical concepts. Dedicated to providing high-quality study materials for BTSC Work Inspector aspirants. Founder of ITI Job 4U, helping students achieve their career goals.