1. How Does An A.C. Generator Produce Electricity?
Answer: Prime Mover, Such As A Steam Or Hydro Turbine, Is Required To Provide Mechanical Power Input To The Alternator In Order To Generate Electricity. Due To A Polarity Change In The Rotor Poles (I.e., N-S-N-S), Voltage Is Generated And Has A Sinusoidal Waveform As The Rotor Poles Move Beneath The Armature Conductors That Are Mounted On The Stator.
2. Why Are Over Voltage And Over Current Relays Needed When Voltage Increases And Current Increases As Well? Is It Possible To Measure Over Voltage And Over Current Using Simply Current Measurements?
Answer: No, As Most Loads Are Non-linear In Nature, We Are Unable To Detect An Overvoltage By Merely Monitoring The Current. Rather, The Current Increases Both In The Event Of An Overvoltage And An Under Voltage.
Thus, Over Voltage And Over Current Protection Are Entirely Distinct From One Another. The Purpose Of An Over Voltage Relay Is To Detect Excessive Voltages And Safeguard The System Against Insulation Failure And Fire. By Detecting Internal Short Circuits, Overload Conditions, And Ground Faults, Overcurrent Relays Help Lower The Danger Of Fire And System Failure.
3. What Is An Alternator's Power Factor When There Is No Load?
Answer: The Alternator's Synchronous Impedance Is What Causes The Angle Difference When There Is No Load. As A Result, It Ought To Lag Zero Like An Inductor.
4. With A Three-pin Plug And A 220v Ac Rating, 6 Amp. Why Does The Earth Pin's Diameter Differ From The Other Two's? What Is The Aim Of It?
Answer: Due To The Fact That The Conductor's Diameter And Current Flow Are Inversely Related. Thus, Excessive Currents Are First Avoided In The Earth Link Terminal In The Event That A Short Circuit Occurs In The System. ( Resistance Value Falls As R=PL/A Area Of The Conductor Grows).
5. If We Should Maintain A Consistent Frequency, Then Why Is It Only 50 Hz And 60 Hz And Not Other Frequencies Like 42, 90, 58, 35, Or Anything Else?
Answer: The Frequency Can Be Set To Any Frequency You Choose, But You Will Need To Build Your Own High-voltage Transformers, Motors, And Other Equipment. Because Equipment Is Designed To Function At These Frequencies And The World Maintains A Standard At 50 Hz Or 60 Hz, We Keep The Frequency At 50 Hz Or 60 Hz.
6. Where Is The Tap Attached In A Tap Changing Transformer? Is It On The Primary Or Secondary Side?
Answer: Due To Low Current, Tapes Are Linked To The High Voltage Winding Side. Sparks Will Occur During Tap Changing Operation If We Connect The Tapings To The Low Voltage Side Because Of The High Current.
7. Since A Capacitor Is A Load-free Component, Why Does The Ampere Meter Register Current When The Breakers In The Capacitor Bank Close?
Answer: Active And Reactive Loads Are The Two Types Of Electrical Loads That Are Known To Exist. The Capacitor, Whose Factor Is ISIN, Is A Reactive Load That Is Not Regarded As A Load. Because The Meter Displays The Current RMS Value, Its Design Is Predicated On The Current RMS Value.
8. What Kinds Of Power Are There In Electrical Power?
Answer: When Discussing Electrical Power, Three Different Forms Of Power Are Typically Considered. They're
· Visible Power
· Static Force
· Reactive Energy
9. Why Is A Fuse Placed In The Phase Of An Ac Circuit And A Link Placed In The Neutral?
Answer: The Link Is Delivered In A Link Form To Resist Large Amps And Is Provided At A Neutral Common Point In The Circuit From Which Different Connections Are Obtained For The Separate Control Circuit. However, The Fuse In The Ac Circuit's Phase Is Made In Such A Way That The Fuse Rating Is Solely Determined For That Specific Circuit, Or The Load. Therefore, In The Event Of A Malfunction, The Fuse Associated With That Specific Control Circuit Alone Will Blow.
10. Why Utilize A Voltage Clamp At A High Transmission System? How Come ACB Isn't An Option?
Answer: Since The Die Electric Strengths In VCBS Are Eight Times Greater Than Those Of Air, Vacuums Actually Have Higher ARC Quenching Properties Than Air. That Is Always Air Used In Lt And Vacuum Utilized In HT Breakers.
11. What Kind Of Power Losses Occur In Electrical Machines That Rotate?
Answer: Copper Losses, Core Losses, Mechanical Losses, And Stray Losses Are The Four Types Of Power Losses In Spinning Electrical Machinery.
12. What Distinguishes A Delta-delta Transformer From A Delta-star Transformer?
Answer: Delta-delta Transformer Is Utilized For Voltage Changes At Either The Generating Or Receiving Station; That Is, It Is Typically Used In Situations Where The Voltage Is High And The Current Is Low. A Distribution Transformer Known As A Delta-star Is Utilized To Address Step-down Voltage Problems. Its Neutral Secondary Star Is Employed As The Return Path.
13. What Distinguishes An Alternator From A Generator?
Answer: Two Machines That Transform Mechanical Energy Into Electrical Energy Are The Generator And Alternator. The Structure Of Each Differs, But The Electromagnetic Induction Principle Is The Same In Each. In Contrast To An Alternator, Which Has A Stationary Armature And Rotating Magnetic Field For High Voltages But Uses A Rotating Armature And Stationary Magnetic Field For Low Voltage Output, A Generator Maintains A Stationary Magnetic Field And A Rotating Conductor That Rolls On The Armature With Slip Rings And Brushes Riding Against Each Other. As A Result, It Converts The Induced Emf Into Dc Current For An External Load.
14. Why Are KVA Ratings For Transformers Used?
Answer: We Just Specify The VA Rating; Power Factor Is Not Taken Into Account Because The Transformer's Power Factor Depends On The Load. Since Power Factor Is Dependent On Motor Construction, Motor Ratings Are Expressed In Kilowatts And Take Power Factor Into Account.
15. What Kind Of Motor Is Used In Trains, What Is The Supply Rating That Is Utilized, And What Is The Working Principle?
Answer: The Trains Have Dc Series To Provide High Starting Torque During Start-up, And The Working Voltage Is 1500 Volts Dc.
16. What Are The Benefits Of Using An Induction Motor With A Star-delta Starter?
Answer: (1) The Lowering Of Current During The Motor's Startup Is The Primary Benefit Of Utilizing A Star Delta Starter. Three To Four Times The Current Of Direct Online Starting Is The Starting Current. (2). As A Result, There Are Less Voltage Drops When The Motor In A System Starts Up And There Is Less Starting Current.
17. What Losses Do Transformers Have?
Answer: Copper Loss And Magnetic Loss Are The Two Main Causes Of Transformer Losses. The Wire's Resistance Is What Leads To Copper Losses (I2R). Hysterics In The Core And Eddy Currents Are The Sources Of Magnetic Losses. After The Coil Has Been Coiled, Copper Loss Is A Constant And May Be Measured. The Hysteretic Loss Is Constant At A Given Voltage And Current.
However, The Eddy-current Loss Varies Depending On The Frequency That Passes Through The Transformer.
18. What Is Power Factor, Please? Is It Appropriate To Set It High Or Low? Why?
Answer: High Power Factor Is Necessary For The System To Operate Smoothly. There Will Be Greater Losses With A Low Power Factor. It Is The Proportion Of Visible Power To Genuine Power. Ideally, It Must Be 1.
If It Is Too Low, Equipment Overloading And Cable Overheating Will Happen. If The Value Is Higher Than 1, The Load Will Function As A Capacitor, Supplying The Source And Resulting In Tripping.(If PF Is Low, For Example, 0.17, More Current Must Be Drawn (V Constant) To Satisfy The Real Power Load, Which Increases Losses.
If PF Is High, For Example, 0.95, Then Less Current (V Constant) Must Be Drawn To Satisfy The Real Power Load, Which Will Reduce Losses.
19. How Many Different Kinds Of Cooling Systems Does It Convert?
Answer: 1. Onan (Natural Oil And Air)
2. Oil Natural, Air Forced, Or ONAF
3. OFAF (Driven By Air And Oil)
4. Direct Oil, Water Pushed, Or ODWF
5. Oil Forced Air Forced (OFAAN)
20. What Distinguishes A Lightning Arrestor From A Surge Arrestor?
Answer: Lightning Arrestor Is Placed Outdoors, Where Lightning Strikes Are Grounded. In Contrast, A Surge Arrestor Is Placed Inside, Where It Consumes Energy And Neutralizes The Effect Of Surges.
21. What Is An AVR, Or Automatic Voltage Regulator?
Answer: Automatic Voltage Regulator Is Shortened To AVR. It Is A Crucial Component Of Synchronous Generators Since It Regulates The Generator's Excitation Current, Which In Turn Regulates The Output Voltage. As A Result, It Has Control Over The Generator's Reactive Power Output.
22. Which Motor — A DC Motor, An Induction Motor, Or A Synchronous Motor — has A Higher Starting Torque And Starting Current?
Answer: The Starting Torque Of Dc Series Motors Is High. The Dc Series Motor Cannot Be Started Without A Load, However The Induction And Synchronous Motors Cannot Be Started While They Are Loaded.
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