Electrical4u- Electrical Engineering


Electrical4u is one of the best electrical engineering Student as well electrical employees. In this we have written all the article with practical explanation. Electrical have developed below article with the Best strong team and they are having more than 20 years’ experience in electrical maintenance, electrical erection, commissioning, designing, Testing, teaching etc. here you can find out the list of electrical4u website article in this home page. Our Explanation little bit difference from the text book, because we have explained them practically as well as theoretically. Also you can request here for getting your favorite article with our electrical4u website. We publish the article within a week from the date of your request. Electrical4u website contains many informative article such as alternator, transformer, transmission line, Protection, Practical related article, etc. Also you can easily find out the list of article have mentioned below…


  1. How to calculate NGR resistance value?
  2. What is alternator All about alternator parts Overview for beginner
  3. What is synchronous speed of an Alternator


  1. 15 Difference Between MCB and RCCB
  2. 7 Types of Voltage Level ELV LV MV HV EHV Ultra High Voltage
  3. 8 Difference Between ELCB and RCCB
  4. Difference Between Cell and Battery
  5. Difference Between Conventional Current and Electron Current
  6. Difference Between Copper Cable and Aluminium Cables
  7. Difference Between CT and PT Current Transformer & Voltage Transformer
  8. Difference Between Floating Charger, Boost Charger and Trickle Charger
  9. Difference Between IDMT DT and Instantaneous Relays
  10. Difference Between Inter Turn Short And Internal Short
  11. Difference Between Multi meter Megger and Series Test Lamp
  12. Difference Between Power Transformer and Distribution Transformer
  13. Difference Between RYB and UVW
  14. Difference Between Shunt Reactor and Series Reactor
  15. Difference between Surge Arrester, Lightning Arrester and Lightning Rod
  16. Difference Between Voltage and EMF
  17. Electrical Standards For Contactors AC1, AC2, AC3, AC4, DC1, DC2 DC3
  18. Top 19 Difference Between ACB, VCB and SF6 [Video included]
  19. Top 7 Difference Between Relay And Contactor
  20. Top 8 Difference Between Isolator and Circuit Breaker

Electrical Basic

  1. 2 Ways We Can Save Power in Your House
  2. AC DC Full Load Current Calculation Formula
  3. Alternating Current Easy to Understand For Student
  4. Alternating Current’s Important Terms and Condition’s Definition
  5. Basic Concept of Bucholzz Relay Working Principle
  6. Basic Concept of DC Generator and Types of DC generator
  7. Basic Differential Relay Working Function
  8. Basically What is conductor, Insulator, Semiconductor
  9. Conditions For Transformer Parallel Operation
  10. Control Circuit Control Supply Power Circuit Power Supply Definition
  11. CT Operated Thermal Over Load Relay Current setting Calculation
  12. Current Divider Rule For Easy Understanding
  13. DC Motor Nameplate Details Explantion
  14. Earthing Procedure for Electrical Panel & Home Appliances
  15. Faraday’s Law Electromagnetic Induction
  16. Fleming Left Hand Rule- Easy Remembering Tips
  17. Fleming Right Hand Rule- Easy Remembering Tips
  18. Harmonic In Electrical | How Electrical Harmonics Occurs in Power system
  19. History of Electrical Engineering
  20. How To Make A Electrical Starter and Power Circuit
  21. How to Measure Magnetic Flux Using Magnetometer
  22. How to Measure Voltage and Current
  23. How to Read Alternator Nameplate Details 31.5MVA , 4 Pole, Synchronous Alternator
  24. Identification of Motor Frame Size 132M & Motor EFF class EFF1 EFF2
  25. Indian Standard IS International Electromechanical Commission IEC
  26. Isolation Transformer | Purpose Of Isolation Transformer
  27. Kirchhoff’s Voltage Law Kirchhoff’s Current Law Easy Understanding
  28. Leading Power Factor And Lagging Power Factor
  29. Line Voltage to Phase Voltage Line Current to Phase Current Relationship
  30. Lux Meter
  31. Magnetic Field
  32. Power Factor Improvement | Reactive Power Compensation Methods
  33. Power Transformer & Distribution Transformer
  34. Relationship Between Work, Energy and Power
  35. Residual Current Circuit Breaker – RCCB
  36. SI Units System
  37. Significance of Leakage Reactance of Transformer
  38. Torque Equation of Three Phase Induction Motor
  39. Types of Capacitors Based on Material Used
  40. Vector Sum Three Phase Current
  41. Voltage Divider or Potential Divider
  42. Voltage Source
  43. What is an electric charge? Coulombs Law of electrical charge
  44. What is an electric charge? Coulombs Law of electrical charge
  45. What is Balance Load & Unbalance Load EEE Student
  46. What is Battery
  47. What is Capacitance, Capacitor Series and Parallel Connection
  48. What is Capacitor Basic Concept Of Capacitor
  49. What is Conductance
  50. What is Conventional Current and Electron Current
  51. What is Current Source
  52. What is Cycle of Alternating Current
  53. What is Delta connection in Three Phase Power System
  54. What is Dielectric Material
  55. What is Direct Current Simple Practical Explanation
  56. What is Electric Circuit and Electronic Circuit
  57. What is Electric Current, Fundamental Types Of Current
  58. What is Electric Field, Electric Field Intensity, Electric Field Density
  59. What is Electrical Network
  60. What is Field in Physics, Types Of Field in Electrical System
  61. What is Flux and Types Of Flux
  62. What is Free Electron and Basic Free Electron Concept?
  63. What is Free Electron and Basic Free Electron Concept? Copper Orbit Structure
  64. What is Frequency and How To Measure Frequency
  65. What is Impedance Reactance Impedance Triangle
  66. What is Instantaneous Current
  67. What is Magnetic Flux
  68. What is Meant by Open Circuit
  69. What is Motor? How Motor Works With Graphical Presentation
  70. What is MPCB Motor Protection Circuit Breaker
  71. What is Neutral Why Neutral is required in Single Phase Power Distribution
  72. What is Ohms Law Simple Concept for EEE student
  73. What is Phase,Phase Angle,Phase Difference Easy Understanding
  74. What is Power Factor & Power Triangle
  75. What is Power System, How Power system Works
  76. What is Pure Inductor Definition, Self Inductance and Mutual Inductance
  77. What is Reactive Power
  78. What Is Resistance? Resistive of the Resistor & One Ohm Resistance
  79. What is Resistor Resistance in series and Parallel Circuit
  80. What is Short Circuit
  81. What is Slip of the Induction motor
  82. What is Slip ring induction motor Practical explanation and Pictured
  83. What is Star Connection in Three Phase Power System
  84. What is Temperature
  85. What is Voltage, Basic Concept of Voltage For Student
  86. What is Waveform
  87. Why CT secondary should not Open condition- Live Test Demo
  88. Why PT burden is high Compare with CT burden?
  89. Why Star delta starters are preferred for higher HP motor
  90. Working Function of Radio meter

Full Electrical Definition

  1. Full Definition Click This
  2. Definition for Circuit diagram and Common Wiring Scheme-I
  3. What is Step potential and Touch Potential and Calculation

Electrical Gate Questions

  1. Electrical Machines Objective Type Questions For Gate Preperation-1
  2. Electrical Machines Objective Type Questions Gate Preparation-2 Transformer
  3. Electrical MCQs Gate Preparation Power Generation
  4. Power systems MCQs Gate Preparation Power generations-2
  5. Power systems MCQs Gate Preparation Power Transmission Generation-3
  6. Power systems Objective Type Questions Gate Preparation Power generations-1

Electrical MCQs

  1. Click This

Electrical License

  1. 8 Types of Electrical License in Tamilnadu
  2. Electrical license Renewal in Tamilnadu Supervisor Contractor & Wireman
  3. Power Generating Station Operation & Maintenance Competency Certificate in Tamilnadu


  1. How VFD Saves Power & Basic Concept of VFD
  2. VFD DOL Changeover circuit- VFD Bypass Arrangement
  3. VFD Start Stop Through DCS Remote Local
  4. VFD start stop wiring diagram
  5. Why line chokes are used in VFD

Induction motor

  1. Different Types of duties in motor construction
  2. How Induction Motor as a rotating Transformer
  3. How to Run Three Phase Motor on Single Phase Power Supply
  4. Induction Motor Interview Question
  5. Slip ring induction motor SRIM vs squirrel cage induction motor SCIM
  6. Synchronous Watt
  7. Types of Encloser employed in induction motor
  8. Types of insulation class motor winding Technology
  9. What is skewing of an induction motor?
  10. Why Slip ring Induction motor is preferred for High starting Torque application

 Interview Questions

  1. 7 Purpose of NGR Neutral Grounding Resistor Transformer & Generator
  2. Arc Horn are used in High Voltage Transmission Line Why?
  3. Electric Shock | How Does human body get electric shock
  4. Ferrite Core On Cable | Why Ferrite Core | Working Principle
  5. How Does Series Reactor Reduce Harmonic
  6. Main Purpose of Damper Winding in Generator
  7. Most Dangerous AC Shock or DC Shock
  8. Purpose of Chokes in Tube Light
  9. Reason For Transformer Core Saturation
  10. Single Phase System vs Three phase System
  11. Transformer Taps Are Provided On High Voltage Side Why?
  12. What Happen Capacitor Bank Connected in no load
  13. What happens if DC supply given to the Inductor
  14. What is Cogging of Induction Motor Definition and Explanation
  15. What is Crawling of Induction Motor Definition & Simple Explanation
  16. What is Electrical Grid
  17. What is The Purpose Of Stockbridge Damper In Transmission Line
  18. Why 25kV is used in Railway Traction System
  19. Why 60 Watts incandescent Bulb Glow in Yellow color
  20. Why Aluminium and Copper Vessels & Pot not Used in Induction Stove
  21. Why Are Alternators Rating in KVA or MVA
  22. Why Battery Cannot Store AC voltage
  23. Why Capacitor and Inductor are used in Filtering Circuit
  24. Why Capacitor Has Leading Power Factor
  25. Why capacitor is required for Single phase motor
  26. Why Capacitors Use As High Voltage Protection
  27. Why DC Does Not Have Power Factor ?
  28. Why DC Voltage is preferred for Control circuit? 
  29. Why Does Bird Not Get Shock on Transmission lines?
  30. Why Earth Pin is Plastic Thicker and Longer
  31. Why Earthing Transformer are used
  32. Why High Voltage is Preferred to Transmit the Power
  33. Why in India 11kV, 22kV, 33kV, 66kV, 132kV…
  34. Why India has 50 Hz Power System and US has 60 Hz 110 Volts Power System
  35. Why induction motor Takes high starting current
  36. Why Inductor Has Lagging Power Factor
  37. Why Inductors Use In Filtering Circuit and VFDs
  38. Why is Battery United AmpsHour AH
  39. Why Lighting Transformer Used for Lighting Loads
  40. Why Permanent magnet generator (PMG) poles are high
  41. Why PT and CT Terminals are Star Connected
  42. Why Stones are used in Transformer Yard & Switchyard?
  43. Why Tertiary Winding is used in transformer?
  44. Why VFD Duty Motor Frame Size is Higher Than Normal Motor
  45. Why we should not give dc supply to Transformer
  46. Why Wind Turbine Has Only Three Blades Not More or Less
  47. Why Zig-Zag Winding Transformer Used

NamePlate Details

  1. How to Read CT Current Transformer Nameplate Details
  2. How to Understand Motor Nameplate Details-ND 280 M/S/L
  3. PT Nameplate Details Explanation
  4. SF6 Circuit Breaker Nameplate Details Explanation
  5. Submersible Pump Nameplate Details
  6. Transformer Name Plate Details Fully Explained
  7. What is motor connection diagram 302 in Nameplate details

Practical Electrical

  1. 10 Facts about Electricity in Human Body
  2. Active and Passive Components
  3. ELCB Earth Leakage Circuit Breaker Working Principle
  4. Electrical Cable lugs Crimping Procedure For Beginner
  5. Electrical Panel & Types of Electrical Panels used In Industry
  6. Electrical Supervisor License in Tamilnadu
  7. Energy consumption of your ceiling Fan
  8. Energy consumption of your phone charger without connecting your phone
  9. How Centrifugal Switch Works
  10. How to Avoid cable over Heating at Screw Terminal
  11. How to calculate current carrying capacity of Carbon Brushes
  12. How to Read & identify Bearing Number
  13. How to Repair Electrical Wire Insulation Failure
  14. IP Enclosure Ratings & Standards Electrical Equipments
  15. LT Panel HT panel Shutdown Procedure
  16. MCB Working Principle and MCB Rating Avoid MCB failure
  17. MCCB Working Principle MCCB Rating and MCCB Current Setting
  18. Normally Open (NO) | Normally Closed (NC)
  19. Resistance split-phase motor induction motor
  20. What is Busbar Current Carrying Capacity Calculation 5 Types of Busbar
  21. What is Electromechanical Components?
  22. Why Carbon brushes are selected, How to Select Good carbon brushes
  23. Top 10 Electrical Website for Electrical Engineering Students

Protection Relays

  1. 100% Stator Earth Fault Protection of Generator
  2. 6 Types of Over Current Relay Used in Power System Protection
  3. 7 Simple Ways to Identifying CT Polarity
  4. Advantage of Neutral Grounding Transformer NGT
  5. Anti-Pumping relay diagram and Working Function Explanation
  6. Backup impedance Protection Working Principle (21G)
  7. Bus Bar Differential Protection or Circulating Current Protection
  8. Busbar Protection & Frame Leakage Protection Working Principle
  9. Check Synchronous Relay Working Principle SKE Relay ANSI Code 25
  10. Classification Generator tripping Scheme Class A, Class B & Class C
  11. Contact Multiplier Relay Working Function & Wiring diagram
  12. CT Supervision Relay Working Principle
  13. Current Based Relay | Voltage Based Relay
  14. Dead Machine Protection Working Principle – 94G ANSI Code
  15. Directional Over Current & Non Directional Over Current Protection Working Principle
  16. Distance Protection Working Principle & Fault Location Detection
  17. End Fault Protection Working Principle
  18. Forward & Reverse Direction of Induction Motor and DC Motor
  19. Generator and Transformer Unit Biased Differential Protection
  20. Generator Over Fluxing or Over Excitation Protection 24 G
  21. High Impedance Differential Protection Low Impedance Differential Protection
  22. How To Basic design and Relay Basic operation
  23. How to Calculate Stabilizing Resistor for High Impedance Differential Protection
  24. Local Breaker Backup Protection LBB 50Z or 50BF
  25. Lockout Relay Working Function 86
  26. Loss of Excitation Protection Working Principle – 40
  27. Low Forward Power Protection 32F
  28. Mater Trip Relay 86 Working Function and Significance of Master Trip Relay
  29. Merz Price Differential Protection for Generators
  30. Merz Price Differential Protection for Transformer
  31. Motor Protection Relay MPR Relay Working Principle Higher HP & High Voltage Motor
  32. Negative Sequence Relay Operation 59_2
  33. Neutral Displacement Relay Operation- 59N
  34. Neutral Voltage Protection -59GN- 95% stator Earth fault protection
  35. Open Delta & Broken Delta Configuration
  36. Over Frequency Protection Working Principle -81O
  37. Over Voltage Protection Working Principle 59
  38. Partial Differential Protection | Scheme | Working Principle
  39. Percentage Differential Relay or Biased Differential Protection
  40. Phase Fault Protection | Induction Motor Protection
  41. Phase Reversal Protection | Induction Motor Protection
  42. PLC DCS Start Stop Wiring diagram
  43. Plug Setting Multiplier & Time Setting Multiplier
  44. Pole Discrepancy Protection Working Principle – 52 PD
  45. Pole Slip Protection Out of Step Protection 78PS Working Principle
  46. Primary and Backup Protection Working Principle
  47. Protective Relaying Terminologies Definition
  48. PT Fuse Failure Relay Working Principle VTFF
  49. Purpose of Unit Auxiliary Transformer (UAT)
  50. Rate Of Change Of Frequency (ROCOF) Protection df/dt Working Principle
  51. Relay Codes for all Relay From 1 to 150 Numbers
  52. Restricted Earth Fault Protection 64R Working Transformer
  53. Reverse Power Protection Working Principle -32R
  54. Rotating Diode Failure Relay Working Principle
  55. Rotor Earth Fault Relay 64R Working Function
  56. Single Phase Preventer Working Principle | Induction Motor Protection
  57. SOTF Relay Working Principle – Switch On To Fault protection
  58. Standby Earth Fault Relay Operation 51N
  59. Stub Protection Working Function
  60. Summation Current Transformer Calculations
  61. Symmetrical Faults & Unsymmetrical Faults
  62. Tan-Delta Test – Finding Insulation Ageing Loss Angle Test
  63. Trip Circuit Supervision TCS Relay Working Function and Operation
  64. Under Frequency Protection Working Principle – 87U
  65. Under Voltage Protection Working Principle 27
  66. Unit Auxiliary Transformer (UAT) Differential Protection 87UAT
  67. Unrestricted Earth Fault Protection Working Priciple
  68. Vector Surge Relay Working Principle | Main Decoupling Relay | MRN Relay
  69. Voltage Restrained Over Current relay Basic concept -51VR VOC
  70. What is Circuit Breaker & Rating of Circuit Breaker
  71. What is Fault in Electrical Power System
  72. What is Ground Fault and Earth Fault
  73. What is Relay Basic Explanation
  74. What is Relay Coordination
  75. What is Sequence Impedance
  76. What is Symmetrical components Positive, Negative, Zero Sequence
  77. What is The Use Of Knee Point Voltage
  78. What is Through Fault
  79. Zone of Protection System


  1. Cheap DOL starter – DCS/Remote/Local Start/Stop
  2. How to avoid star delta Timer failure in star delta starter
  3. Star Delta starter wiring diagram with Full Explanation


  1. 4 Different Types of Current Transformers
  2. Basic Concept of Transformer
  3. CT Testing | Polarity Test | Ratio Test | Insulation Test | Burden Test
  4. Current Transformer
  5. CVT in Electrical Capacitive Voltage Transformer CVT
  6. Droop CT – Droop Current Transformer
  7. Equipotential shielding of current transformer
  8. Loading Transformer Working Principle
  9. Potential Transformer Working Principle
  10. Relationship of Frequency Vs KVA Output or Rating of Transformer
  11. Sweep Frequency Response Analysis -SFRA Test Procedure
  12. Three Phase Transformer vector group and Significance of vector Grouping
  13. Three Phase Transformer Vector Grouping Significance of Vector Grouping
  14. Transformer Bushing Operating Principle
  15. Transformer Core Construction Details
  16. What is Percentage Impedance & Calculate Percentage Impedance?
  17. Why transformer Rating in KVA exact answer


  1. Auto Reclosing Scheme In Transmission System
  2. Bus Scheme | Types of Bus Scheme Are Used In Power System
  3. Corona Definition | Avoid Corona | Purpose of Corona Ring | Advantage
  4. Difference Between AC Motor and DC Motor
  5. Difference Between Alternating Current and Direct Current
  6. Difference Between Capacitor and Condenser
  7. Difference between HVDC Transmission System and EHV transmission System
  8. Difference Between Synchronous motor and Induction Motor
  9. Difference Between Underground Cable and overhead cable
  10. Electrical Substation (SS)
  11. Electro static Precipitator working Principle
  12. Ferranti Effect Explanation | How to Reduce Ferranti effect
  13. Insulator | Types Of Insulators are Used In AC Transmission System
  14. One and Half Bus System & One And Half Circuit Breaker Scheme
  15. Pre Closing Trip Supervision | Post Close Trip Supervision
  16. Short Transmission Line Definition Equivalent circuit Phasor diagram Transmission Efficiency
  17. Source of Electrical Energy
  18. Types Of HVDC Transmission System
  19. Types of Transmission Lines in Power System
  20. Wave Trap Working Function & Purpose of Line Trap
  21. What is Aviation Lamp
  22. What is Creepage and Clearance Distance of Insulator?
  23. What is OSR Protection or Oil Surge Protection
  24. What is Potential Gradient in Electrical, Use of Potential Gradient Calculation
  25. What is Proximity Effect | Reduce Proximity Effect
  26. What is Skin Effect | Reduce Skin Effect in Transmission Lines
  27. What is The Rating of Icu Ics Icw Icm of Circuit breaker
  28. Why tester does not work on DC