250+ Electrical Engineering Interview Questions

 Hello Electrical Engineering students 

Interviewing for a Electrical engineering job can be tricky, but we’re here to help!

Don't get discouraged if the interviewer doesn't ask any technical questions. The interview is about more than just your expertise. It's about your communication skills, problem-solving abilities, and how well you work in a team setting. With these things in mind, you'll be prepared to answer interview questions.

⇒ 1 ton is equal to how many watts? 

⇒ A (50/60 Hz) Transformer. Which one will give more Output? 

⇒ Advantages of PLCs than Hard wired Relay? 

⇒ Advantages of vvvf drives over non vvvf drives for EOT cranes? 

⇒ ARC 

⇒ Battery banks are in connected in series or parallel and why? 

⇒ Bundled Conductors and C

omposite Conductors Difference? 

⇒ Can we store AC in batteries instead of DC? 

⇒ Capacitor is load free component but why ampere meter shows current when capacitor bank breaker close? 

⇒ Comment on the working principle of operation of a single-phase transformer. 

⇒ Comment on the working principle of operation of a single-phase transformer. 

⇒ Compare JFET’s and MOSFET’s. 

⇒ Corona Ring on Surge Arresters and other EHV equipment 

⇒ Could you explain about reverse power relay? 

⇒ Define IDMT relay? 

⇒ Define stepper motor. What is the use of stepper motor? 

⇒ Define the followin? Average demand, Maximum demand, Demand factor, Load factor. 

⇒ Define the following terms:-

- Reliability,

- Maximum demand,

- Reserve-generating capacity,

- Availability (operational). 

⇒ Define the following: Average demand, Maximum demand, Demand factor, Load factor. 

⇒ Define Voltage types? 

⇒ Define what is difference between fuse and breaker? 

⇒ Define what is power quality meter ? 

⇒ Define What is the function of anti-pumping in circuit breaker? 

⇒ Describe DC motor Braking methods? 

⇒ Difference between a four point starter and three point starter? 

⇒ Difference between megger test equipment and contact resistance meter test instruments? 

⇒ Difference between Solid Conductor and Stranded Conductor? 

⇒ Difference between Thermal and Nuclear Power Plants? 

⇒ Different Levels of SCADA? 

⇒ Different Transformers in Thermal Power Plant? 

⇒ Do transients occur in power lines only? 

⇒ Enlist types of dc generator? 

⇒ Explain advantages of storage batteries. 

⇒ Explain advantages of storage batteries? 

⇒ Explain different losses in a transformer. 

⇒ Explain different types of D.C motors? Give their applications. 

⇒ Explain forward resistance, static resistance and dynamic resistance of a pn junction diode. 

⇒ Explain How to determine capacitor tolerance codes? 

⇒ Explain the application of storage batteries. 

⇒ Explain the operation of variable frequency transformer? 

⇒ Explain the process of commutation in a dc machine. Explain what are inter-poles and why they are required in a dc machine. 

⇒ Explain the process of commutation in a dc machine.

Explain what are inter-poles and why they are required in a dc machine. 

⇒ Explain the statement that ” In Inductive circuit, when Inductance (L) or inductive reactance (XL) increases, the circuit Current (I) decrease” 

⇒ Explain the terms real power, apparent power and reactive power for ac circuits and also the units used. 

⇒ Explain the working principal of the circuit breaker? 

⇒ Explain thin film resistors and wire-wound resistors. 

⇒ Explain Transposition of the power lines ? 

⇒ Explain What is use of lockout relay in ht voltage? 

⇒ Factors on which material of station busbar depends? 

⇒ For distribution network which type of Switching scheme is employed? 

⇒ Gas Insulated Substations Advantages Disadvantages ? 

⇒ Give two basic speed control scheme of DC shunt motor? 

⇒ How can you relate power engineering with electrical engineering? 

⇒ How can you start-up the 40w tube lite with 230v AC/DC without using any choke/Coil? 

⇒ How do you select a cable size (Cu & Al) for a particular load? 

⇒ How does a battery produce its potential difference (voltage)? 

⇒ How does Zener phenomenon differ from Avalanche breakdown? 

⇒ How electrical power is generated by an A.C Generator? 

⇒ How energy is generated in Nuclear power plant? 

⇒ How Generator Transformer is cooled in Thermal Power Plant? 

⇒ How many types of colling system it transformers? 

⇒ How much Watts Solar Panel We need for our Home Electrical ? 

⇒ How to calculate capacitor bank value to maintain unity power factor with some suitable example? 

⇒ How to Calculate the charging Time and Charging current for battery Charging? 

⇒ How To Calculate Your Electricity Bill? 

⇒ How to determine alternating current frequency? 

⇒ How to determine capacitor tolerance codes? 

⇒ How to Reduce the Ferranti Effect in a Transmission Line? 

⇒ How transients are produced in our system? 

⇒ How tube light circuit is connected and how it works? 

⇒ If I have a 25kVA generator, how many 2 Ton Air conditioner can be used? 

⇒ If one lamp connects between two phases it will glow or not? 

⇒ If we give 2334 A, 540V on Primary side of 1.125 MVA step up transformer, then what will be the Secondary Current, If Secondary Voltage=11 KV? 

⇒ In a Tap changing transformer where is the tap connected, is it connected in the primary side or secondary side? 

⇒ In the motors starting purpose why the armature rheostats at maximum position while the field rheostat is kept in minimum position? 

⇒ In three pin plug 6 Amp. 220v AC rating. why earth pin diameter is higher than other two pin? what its purpose ? 

⇒ Master Terminal Units (MTU) in SCADA systems ? 

⇒ Mention the disadvantages of low power factor? How can it be improved? 

⇒ Mention the methods for starting an induction motor? 

⇒ Name power losses in rotating electrical machines. 

⇒ Name the types of motors used in vacuum cleaners, phonographic appliances, vending machines, refrigerators, rolling mills, lathes, power factor improvement and cranes. 

⇒ Operation carried out in Thermal power stations? 

⇒ Say there is air conditioner of 1Ton, what does that mean? 

⇒ SCADA system applications ? 

⇒ State Maximum power transfer theorem ? 

⇒ State Norton’s Theorem? 

⇒ State the difference between generator and alternator? 

⇒ State the factors, for the choice of electrical system for an aero turbine. 

⇒ State the methods of improving power factor? 

⇒ State Thevenin’s Theore? 

⇒ Sulfur hexafluoride gas (SF6) gas properties 

⇒ Tell me in detail about c.t. and p.t. ?(Company:reliance) 

⇒ Tell us about Various Substation Equipment ? 

⇒ The Main Difference between Active and Passive Components 

⇒ There are a Transformer and an induction machine. Those two have the same supply. For which device the load current will be maximum? And why? 

⇒ Transformer Testing methods ? 

⇒ Transformer works on which principle? 

⇒ Two bulbs of 100w and 40w respectively connected in series across a 230v supply which bulb will glow bright and why? 

⇒ Use of switch mode power converter in real-time basis? 

⇒ Voltage Regulation of Transformer ? 

⇒ What are advantages of PLCs over RTUs? 

⇒ What are Causes of low Power Factor ? 

⇒ What are different Bus bar materials used in Substation? 

⇒ What are different components in PLC? 

⇒ What are different types of busbar arrangement Schemes in Substations? 

⇒ What are different types of circuit breakers employed in thermal power plant? 

⇒ What are different types of Control Systems? 

⇒ What are different types of Induction Motors available? 

⇒ What are different types of Pulverizes? 

⇒ What are different types of Steam boilers used in Thermal Power Plants? 

⇒ What are HRC fuses and where it is used? 

⇒ What are Motor Generator Sets and explain the different ways the motor generator set can be used ? 

⇒ What are the advantage of free wheeling diode in a Full Wave rectifier? 

⇒ What are the advantages of speed control using thyristor? 

⇒ What are the advantages of star-delta starter with induction motor? 

⇒ What are the advantages of VSCF wind electrical system? 

⇒ What are the different auxiliary systems in thermal power plant? 

⇒ What are the different electrical clearances in Substation? 

⇒ What are the different Generator Protections employed in Thermal Power Plants? 

⇒ What are the different losses that occur in thyristor while operating? 

⇒ What are the different methods for the starting of a synchronous motor ? 

⇒ What are the different substation components? 

⇒ What are the effects of transients? 

⇒ What are the full forms of ASME and ASTM? 

⇒ What are the major electric systems in Thermal Power Plant? 

⇒ What are the particles used in nuclear fission? 

⇒ what are the points to be consider for MCB(miniature circuit breaker selection? 

⇒ What are the possible causes for low power factor? 

⇒ What are the transformer losses? 

⇒ What are the types of power in electrical power? 

⇒ What are the various kind of cables used for transmission? 

⇒ What are Transformer parallel operation conditions ? 

⇒ What are transients in power system? 

⇒ What does Central Processing Unit (CPU) of PLC consists? 

⇒ What does quality factor depend on in resonance? 

⇒ what happen if we give 220 volts dc supply to d bulb r tube light? 

⇒ What happen when Induction motor run at synchronous speed? 

⇒ What happens if i connect a capacitor to a generator load? 

⇒ What is 2 phase motor? 

⇒ What is a differential amplifier? Also, explain CMRR. 

⇒ What is a feedback in Control System? 

⇒ What is a System? 

⇒ What is a transmission voltage? 

⇒ What is ACSR cable and where we use it? 

⇒ What is an exciter and how does it work? 

⇒ What is Automatic Voltage regulator(AVR)? 

⇒ What is basic difference between transformer and inducter? 

⇒ what is boucholz relay and the significance of it in to the transformer? 

⇒ What is Cavitation and disadvantages of Cavitation? 

⇒ What is Chain reaction and how it is controlled in Nuclear reactor? 

⇒ What is Control System? 

⇒ What is derating?, why it is necessary, it is same for all means for drives, motors,and cables. 

⇒ What is difference between operating voltage and input voltage? 

⇒ What is difference between terminal voltage and generated voltage? 

⇒ What is different between resistance grounding system and resistance earthing system? 

⇒ What is electric traction? 

⇒ What is electrical diversity factor in electrical installations? 

⇒ What is encoder, how it function? 

⇒ What is excitation current or magnetising current in Transformer? 

⇒ What is excitation? 

⇒ What is ferrantic effect? 

⇒ What is fertile material and fissile material? 

⇒ What is Forebay and its importance? 

⇒ What is frantic effect? 

⇒ What is Frequency Domain Analysis? 

⇒ What is Frequency Response Analysis and its advantages? 

⇒ What is Frequency Response? 

⇒ What is half life and its significance? 

⇒ What is Harmonics Distortion and its effect in Power System 

⇒ What is Holding current? 

⇒ What is Hydrogen Scavenging process in Generator? 

⇒ What is inrush current? 

⇒ What is Islanding Operation ? 

⇒ What is Latching current? 

⇒ What is Main Difference b/w Electrical and Electronics Engineering? 

⇒ what is meant by armature reaction? 

⇒ What is meant by insulation voltage in cables? explain it? 

⇒ What is meant by knee point voltage? 

⇒ What is meant by regenerative braking? 

⇒ What is Penstock? 

⇒ What is PI Controllers in Process System? 

⇒ What is Potential Transformer (PT)? 

⇒ what is power factor? whether it should be high or low? why? 

⇒ What is power quality meter ? 

⇒ what is Progrmmable Logic Controllers (PLCs) ? 

⇒ What is rated speed? 

⇒ What is reverse power relay? 

⇒ What is SCAN in PLC ? 

⇒ What is SF6 Circuit Breaker? 

⇒ What is slip in an induction motor? 

⇒ What is Smart Grid? 

⇒ What is steady state and transient stability? 

⇒ What is stepper motor.what is its uses? 

⇒ What is Tailrace? 

⇒ What is the advantage of Slip Ring Induction Motor? 

⇒ What is the advantage of Squirrel Cage Induction Motor? 

⇒ What is the basic loading condition for transformer and its life expectancy? 

⇒ What is the capacity of CPU of Remote Terminal Unit (RTU)? 

⇒ What is the count of hvdc transmission lines in India? 

⇒ What is the difference between a battery and a capacitor? 

⇒ What is The Difference between a VOLTAMETER and a VOLTMETER? 

⇒ What is the difference between delta-delta, delta-star transformer? 

⇒ What is the difference between earth resistance and earth electrode resistance? 

⇒ What is the difference between Electro-magnetic and electro-mechanical transients? 

⇒ What is the difference between electronic regulator and ordinary electrical rheostat regulator for fans? 

⇒ What is the difference between generator and alternator? 

⇒ What is the difference between harmonics and transients? 

⇒ What is the difference between Isolator and Circuit Breaker? 

⇒ What is the difference between isolators and electrical circuit breakers? What is bus-bar? 

⇒ What is the difference between isolators and –>electrical circuit breakers? What is bus-bar? 

⇒ What is the difference between MCB & MCCB, Where it can be used? 

⇒ What is the difference between MCB & MCCB, Where it can be usehe difference between MCB & MCCB, Where it can be used? 

⇒ What is the difference between phase and line voltage? 

⇒ What is the difference between Power Transformers and Distribution Transformers? 

⇒ What is the difference between shunt reactor and line or bus reactor? 

⇒ What is the difference between surge arrestor and lightning arrestor? 

⇒ What is the difference between synchronous generator & asynchronous generator? 

⇒ what is the difference between synchronous generator & asynchronous generator? 

⇒ What is the difference between the feeder and bus bar? 

⇒ What is the different between digital phase converter and ordinary phase converter? 

⇒ What is the effect of positive feedback on stability of the system? 

⇒ What is the emf equation of transformer? 

⇒ What is the first equipment of the substation connected to the incoming transmission line? 

⇒ what is the full form of KVAR? 

⇒ What is the function of anti-pumping in circuit breaker? 

⇒ What is the function of interposing current transformer? 

⇒ What is the Ideal transformer? 

⇒ What is the largest pump in the thermal power plant? 

⇒ What is the main difference between contactor and Starter? 

⇒ What is the main difference between negative terminal and ground terminal of voltage source? 

⇒ What is the main difference between voltage, EMF and a potential difference? 

⇒ What is the main use of rotary phase converter ? 

⇒ What is the normal or average life expectancy of a Transformer ? 

⇒ What is the Polarization index value ? (pi value)and simple definition of polarization index ? 

⇒ What is the power factor of an alternator at no load? 

⇒ What is the Power Supply provided to the RTU? 

⇒ what is the principle of motor? 

⇒ What is the programmable language used in PLC? 

⇒ What is the purpose of Pulverizes? 

⇒ What is the ratio of CT? 

⇒ What is the relation between applied voltage and emf induced with respect to flux wave? 

⇒ What is the Role of Capacitor in AC and DC Circuit? 

⇒ What is the significance of vector grouping in Power Transformers? 

⇒ What is the Significance of voltage per turn? 

⇒ What is the speed variation of the induction motor from no load to full load? 

⇒ What Is The Use For Cable Entry In Control Room? 

⇒ What is the voltage gain or transfer function of amplifier? 

⇒ What is Trash Racks? 

⇒ What is Tunnel Diode? 

⇒ What is use of lockout relay in ht voltage? 

⇒ What is vaccum currcuit breaker.define with cause and where be use it Device? 

⇒ What is water hammering phenomenon? 

⇒ What is “pu” in electrical engineering? 

⇒ What type of cables are used for transmissions? 

⇒ What type of cooling is provided for Generator in power plant? 

⇒ What types domain of Laplace transforms? What behavior can Laplace transform predict how the system work? 

⇒ What will happen if DC supply is given on the primary of a transformer? 

⇒ What will happen if you increase current through a conductor ? 

⇒ What will happen when power factor is leading in distribution of power? 

⇒ What will happen when power factor is leading in distribution of power? 

⇒ What will reduce Neutral currents ? 

⇒ whats is MARX CIRCUIT? 

⇒ Whats the one main difference between UPS & inverter ? And electrical engineering & electronics engineering ? 

⇒ What’s electric traction? 

⇒ When does Proportional (P) Integral (I) Derivative (D) Controllers are Used

⇒ When voltage increases then current also increases then what is the need of over voltage relay and over current relay? 

⇒ When we connect the large capacitor bank in series? 

⇒ Where Servomechanism is used? 

⇒ Where should the lighting arrestor be placed in distribution lines? 

⇒ Which motor has high Starting Torque and Staring current DC motor, Induction motor or Synchronous motor? 

⇒ Which power plant has high load factor? 

⇒ Which type of A.C motor is used in the fan (ceiling fan, exhaust fan, padestal fan, bracket fan etc) which are find in the houses ? 

⇒ Which type of bus arrangement is costlier and more reliable? 

⇒ Which type of motor is used in trains, what is the rating of supply used explain Working principal? 

⇒ Which type of oil is used as a transformer oil? 

⇒ Why AC Needs More Insulation Than DC at Same Voltage Level? 

⇒ Why AC rated in Tons, Not in kW or kVA?

Guide about Air-conditioner and Refrigeration. 

⇒ Why AC systems are preferred over DC systems? 

⇒ Why an ac solenoid valve attract the plunger even though we interchanges the terminal? Will the poles changes? 

⇒ Why back emf used for a dc motor? highlight its significance. 

⇒ Why back emf used for a dc motor? highlight its significance. 

⇒ Why Battery rating in Ah (Ampere hour) and not in VA. 

⇒ Why computer humming sound occurred in HT transmission line? 

⇒ Why DC voltage is not used in transformer? 

⇒ Why Delta Star Transformers are used for Lighting Loads? 

⇒ Why efficiency of transformer is high? 

⇒ Why EHV busbars are hallowed and circular? 

⇒ Why ELCB can’t work if N input of ELCB do not connect to ground? 

⇒ Why electricity in India is in the multiples of 11 like 11kv, 22kv, 33kv ? 

⇒ Why field rheostat is kept in minimum position while armature rheostat at maximum position? 

⇒ Why Human body feel Electric shock ?? n in an Electric train during running , We did nt feel any Shock ? why? 

⇒ Why in a three pin plug the earth pin is thicker and longer than the other pins? 

⇒ Why induction motor develops a torque? 

⇒ Why induction motor draws heavy current at starting? 

⇒ Why Induction Motor name has come? 

⇒ Why is AC systems preferred to DC systems? 

⇒ Why is the starting current high in a DC motor? 

⇒ Why link is provided in neutral of an ac circuit and fuse in phase of ac circuit? 

⇒ Why Low Voltage winding near core of the Transformer? 

⇒ Why most of analog o/p devices having o/p range 4 to 20 mA and not 0 to 20 mA? 

⇒ Why motor are rated as KW while transformer rated in kVA? 

⇒ Why Motor rated in kW/Horsepower instead of kVA? 

⇒ Why Negative Feedback is preffered in the Control System? 

⇒ Why power factor of the transformer under no load is very low? 

⇒ Why Power Plant Capacity Rated in MW and not in MVA? 

⇒ Why SCADA systems are Implemented? 

⇒ Why series motor cannot be started on no-load? 

⇒ Why should be the frequency 50 Hz 60Hz only why not others like 45, 95 56 or anything , why should we maintain the frequency constant if so why it is only 50 Hz 60Hz? 

⇒ Why star delta starter is preferred with induction motor? 

⇒ Why syn. generators are used for the production of electricity? 

⇒ Why temperature rise is conducted in bus bars and isolators? 

⇒ Why the capacitors works on ac only? 

⇒ Why the reactance of a system under fault condition is low and faults currents may raise dangerously high value. ? (With simple example) 

⇒ Why thyristor is considered as Charge controlled device? 

⇒ Why Transformer Rating In kVA, Not in KW? 

⇒ Why transformer ratings are in kva? 

⇒ Why use the VCB at High Transmission System ? Why can’t use ACB? 

⇒ Why we can’t store AC in Batteries instead of DC.or Can we store AC in batteries instead of DC? 

⇒ Why we do 2 types of earthing on transformer (i?)body earthing & neutral earthing , what is function. i am going to install a oo kva transformer & 380 kva DG set what should the earthing value? 

⇒ Why we do transient analysis? 

⇒ Why We Need to Install a Starter with a Motor? 

⇒ Why we use ac system in India why not dc? 

⇒ Why, when birds sit on transmission lines or current wires doesn’t get shock? 

⇒ Will a D.C Shunt Motor operate on an A.C Supply? 

⇒ Will the tranformers work on pulsating dc ? as there occurs a change in magnitude of the flux produced 

⇒ You may have noticed there are fuse and circuit breakers. What is the difference between the both? 

⇒ You would be aware that transformer has an insulating oil, which oil is that?

There are many factors that contribute to a successful interview, but there’s one in particular that’s often overlooked by the interviewee.⁣

Most people spend their time preparing for the 60-second introduction they will give at the beginning of the interview and reviewing answers to some common questions, but completely overlook their handshake.⁣

This little gesture can make or break a candidate in an instant. We may think we don’t do it correctly,

Thank U