when breaker is close at one time by close push button,the anti pumping contactor prevent re close the breaker by close push button after if it already close. This article provides questions asked in a job interview for professional electrical engineering positions, and assists with answering them. Junctions that experience breakdown above 5v are caused by avalanche-effect. Senior Electrical Engineers design, develop, maintain, inspect, and evaluate electrical components and machinery. If we connect tapings to low voltage side, sparks will produce while tap changing operation due to high current. How do you select a cable size (Cu & Al) for a particular load? 114. 127. Electrical Engineering 31 Important Interview Questions With Answers PDF What is the difference between Isolator and Circuit Breaker? 107. 52. 2. If their is high power factor, i.e if the power factor is close to one: 19. whats the one main difference between UPS & inverter ? it has to be ideally 1. if it is too low then cable over heating & equipment overloading will occur. What is slip in an induction motor? generators r used for the production of electricity. Over current relay meant for sensing any Electrical Engineering Interview Questions. It is given by Voc / (Ri + RL). What is the difference between MCB & MCCB, Where it can be used? Copyright 2020 , Engineering Interview Questions.com, 400+ TOP ELECTRICAL Engineering Interview Questions and Answers Pdf- EEE. 180. The armature flux has an important role for the running condition. Most efficient form of storing energy portably. For which device the load current will be maximum? 130. whats the one main difference between UPS & inverter ? communication lines.So we can understand the importance of power measurement through power quality meters. power losses tend to be less because as we minimize the speed the electronic reg. 93. Electron in the outer orbit is known as valence. What does the KVAR means? 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? 102. That y always vacuum used as inHT breaker and air used as in LT . so, interchanging of terminals in ac system does not show any difference. Why link is provided in neutral of an ac circuit and fuse in phase of ac circuit? Which motor has high Starting Torque and Staring current DC motor, Induction motor or Synchronous motor? Mention the methods for starting an induction motor? Hysteresis loss is constant for a particular voltage and current. Explain the terms real power, apparent power and reactive power for ac circuits and also the units used. i Really need it. ups is also two types : on line and offline . What are the advantage of free wheeling diode in a Full Wave rectifier? The voltage induced in secondary coil is known as mutually induced voltage. This requires a large conductor size. By using flux control method:in this method a rheostat is connected across the field winding to control the field current.so by changing the current the flux produced by the field winding can be changed, and since speed is inversely proportional to flux speed can be controlled .armature control method:in this method a rheostat is connected across armature winding by varying the resistance the value of resistive drop(IaRa)can be varied,and since speed is directly proportional to Eb-IaRa the speed can be controlled. The water is obtained in the boiler and the coal is burnt so that steam is obtained this steam is allowed to hit the turbine, the turbine which is coupled with the generator generates the electricity. Series motor are used in Trains, Crane etc. It deals with generation, transmission and distribution of energy in electrical form. 136. while breaking the circuit, the contact terminals will be separated. What are HRC fuses and where it is used? Why series motor cannot be started on no-load? but inverter is start with 2v,24,dc to 36v dc and 20amp to 80amp battery with long time backup. n in an Electric train during running , We did nt feel any Shock ? 57. Define what is difference between fuse and breaker? Availability: As the percentage of the time a unit is available to produce power whether needed by the system or not. supply voltage hence called as back emf. What is bus-bar? thanks, Sir please send me interview and electrical basis mcq pdf qudstion, awesome site for comptative question answer. I thing it’s good one 4 me thanks, Your email address will not be published. This microprocessor, called a digital signal processor (DSP), monitors the phase conversion process, continually adjusting the input and output modules of the converter to maintain perfectly balanced three-phase power under all load conditions. 196. What is the full form of KVAR? How many types of colling system it transformers? What is 2 phase motor? At the time of separation an air gap is formed in between the terminals. Resolution:Isolators are mainly for switching purpose under normal conditions but they cannot operate in fault conditions .Actually they used for isolating the CBs for maintenance. Capacitor is load free component but why ampere meter shows current when capacitor bank breaker close? Why use the VCB at High Transmission System ? As a result, the flux is set. 36. In an AC system this becomes much easier to interupt, as the sine wave current will naturally tend to zero at some point making the current easier to interrupt. State the methods of improving power factor? By putting these value on Relation- Define what is power quality meter ? Thanks. How can you start-up the 40w tube lite with 230v AC/DC without using any choke/Coil? 33. why syn. What is your background? Thanks and best wishes for all engineers Explain How to determine capacitor tolerance codes? 75. ups is also two types : on line and offline . What types domain of Laplace transforms? Aero turbine always keeps going at maximum efficiency point. Why in a three pin plug the earth pin is thicker and longer than the other pins? Explain forward resistance, static resistance and dynamic resistance of a pn junction diode. for railways,trams, trolleys etc). Variable losses or copper losses: when the transformer is loaded, current flows in primary and secondary windings, there is loss of electrical energy due to the resistance of the primary winding, and secondary winding and they are called variable losses. My Mail ID : nayeem_eee@hotmail.com. Now a day, magnetic traction is also utilised for bullet trains. Battery banks are always connected in series in order to get a multiplied voltage where the AH or current capacity remaining same. Below is a collection of 100+ mostly management and behavioral questions I was asked on phone screens and by panels during onsite interviews for engineering management positions at a variety of big-name and top-tier tech companies in the San Francisco Bay Area such as Google, Facebook, Amazon, … for this purpose it mainly used in automation parts. 104. What is the main use of rotary phase converter ? f -frequency MOSFET’s have input impedance much higher than that of JFET’s. Quality factor q depends on frequency and bandwidth. The different methods of starting an induction motor. 44. Maintenance Engineer Interview Preparation Guide . We can have the frequency at any frequency you like, but than you must also make your own motors,high voltage transformers or any other equipment you want to use.We maintain the frequency at 50hz or 60hz because the world maintains a standard at 50 /60hz and the equipments are are made to operate at these frequency. ), number of tray, depth of trench, distance between cables. 15 Toughest Interview Questions and Answers! The more pulses there are per second, the more the energy. As we know that Electrical is having two type of load, Active and Reactive .Capacitor is a reactive load which is not considering as a load,& its factor is Isin@ .Meter is design based on Current RMS value because of it meter is showing the current RMS value. Why Delta Star Transformers are used for Lighting Loads? A fixed width pulse is generated for each cycle. 109. AC or Dynamic Resistance: It can be defined as the reciprocal of the slope of the forward characteristic of the diode. State Thevenin’s Theorem: why earth pin diameter is higher than other two pin? 51. what is boucholz relay and the significance of it in to the transformer? whether it should be high or low? It is usually expressed as a percentage of synchronous speed (Ns) and represented by the symbol ‘S’. Download 70 Question & Answers for HVAC Engineer Interview These technical questions for HVAC interview are the top questions that come any interview for airconditioning, heating or ventilation jobs. Actually the thing is vacuum has high arc quenching property compare to air because in VCB ,the die electric strengths equal to 8 times of air . 106. 59. What is reverse power relay? It is longer because the The First to make the connection and Last to disconnnect should be earth Pin. Super tension cables can transmit voltage 66 kV to 132 kV. 50. or The induced emf developed when the rotating conductors of the armature between the poles of magnet, in a DC motor, cut the magnetic flux, opposes the current flowing through the conductor, when the armature rotates, is called back emf. Sir, can you mail me this in PDF format at sajid.harun@gmail.com. For starting, ignition and lighting of automobiles, aircrafts etc. synchronous machines have capability to work on different power factor(or say different imaginary power varying the field emf. The voltage induced in the primary winding is due to its self inductance and known as self induced emf and can u please send me the pdf form. Low lagging power factor causes a large voltage drop, hence extra regulation equipment is required to keep voltage drop within prescribed limits. Power factor should be high in order to get smooth operation of the system.Low power factor means losses will be more.it is the ratio of true power to apparent power. In some situations, equipment function and operation is monitored and controlled from a remote location where communication is via modem, or highspeed if it is an ac excitor, out put of ac excitor is rectified by rotating diodes and supply dc to main fixed poles.ac excitor is the ac generator whose field winding are stationary and armature rotates. 98. what are the points to be consider for MCB(miniature circuit breaker selection? Which power plant has high load factor? so it is necessary to test this devices for temperature rise. 178. 49. Dc series is in the trains to get high starting torque while starting of the trains and operating voltage is 1500v dc. The effect of armature flu to main flux is called armature reaction. The Zener-breakdown occurs in heavily doped junctions, which produce narrow depletion layers. 163. Why back emf used for a dc motor? Hence the starting current is reduced , the voltage drops during the starting of motor in systems are reduced. By providing more ampere-turns than required, the induction motor can be made to operate on leading power factor like an overexcited synchronous motor. So,I2 = 114.5 Amps. What to look for in an answer: Whether the candidate seems engaged in the idea of answering the question; If the candidate gives thought to a purposeful answer 121. This includes the maximum power from the network and in this case the load resistance is being is equal to the resistance of the network and it also allows the resistance to be equal to the resistance of the network. because of this difference in current ELCB wil trip and it will safe guard the other circuits from faulty loads. Due to existing current flow the air in the gap is ionized and results in the arc. Resolution:Mainly transformer has high inductance and low resistance.In case of DC supply there is no inductance ,only resistance will act in the –> electrical circuit. Explain the application of storage batteries. 24. 83. It is used with generators for charging a number of capacitor in parallel and discharging them in series.It is used when voltage required for testing is higher than the available. The phenomenon when the depletion region expands and the potential barrier increases leading to a very high electric field across the junction, due to which suddenly the reverse current increases under a very high reverse voltage is called Zener effect. So if range is 0-20 mA then we can differentiate whether it is due to broken What are the various kind of cables used for transmission? Zener-breakdown or Avalanche breakdown may occur independently or both of these may occur simultaneously. 9. 87. Give their applications This is usually done by means of a programmed algorithm,especially if any part is digital, while most analog encoding is done with analog 53. 96. internal short circuit, over load condition ,earth fault thereby reducing the system failure & risk of fire.So, for a better protection of the system.It should have both over voltage & over current relay. What is frantic effect? Several coils undergo commutation simultaneously. The parallel resistance of the network can be viewed from the open circuit terminals when all the voltage and current sources are removed and replaced by the internal resistance. By connecting static capacitors in parallel with the load operating at lagging power factor. What are your short ter… That means once side current is going and not returning and hence What is meant by regenerative braking? In starting, the value of back emf is zero. otherwise it’s not possible to ionize the particles in tube. 15. E -Induced emf per phase please sent me electrical interview Question. 81. DC Series motor has high starting torque. but in VCB the medium is vacuum gas. The complete wire wound resistor is coated with an insulating material such as baked enamel. Essentially dc motors are utilized for electric traction systems. Connecting a capacitor across a generator always improves power factor,but it will help depends up on the engine capacity of the alternator,other wise the alternator will be over loaded due to the extra watts consumed due to the improvement on pf. Copper losses are caused by the resistance of the wire (I2R). So always transmission voltage is multiple of 11. What are the advantages of VSCF wind electrical system? What is the different between digital phase converter and ordinary phase converter? What is electrical diversity factor in electrical installations? 7. whats is MARX CIRCUIT? synchronous machines have capability to work on different power factor(or say different imaginary pow varying the field emf. 42. JFET’s have characteristic curves more flat than that of MOSFET is indicating a higher drain resistance. whenever any internal fault occurs in a transformer, the boucholz relay at once gives a horn for some time, if the transformer is isolated from the circuit then it stop its sound itself other wise it trips the circuit by its own tripping mechanism. A breaker is normally used to break a circuit. Pu stands for per unit and this will be used in single line diagram of power distribution and it is like a huge electrical circuit with no of components (generators, transformers, loads) with different ratings (in MVA and KV). Near distribution transformers and out going feeders of 11kv and incomming feeder of 33kv and near power transformers in sub-stations. Dear engineers Forward Resistance: Resistance offered in a diode circuit, when it is forward biased, is called forward resistance. Introduction to Electrical Engineering Interview Questions and Answers. It is an inverse definite minimum time relay.In IDMT relay its operating is inversely proportional and also a characteristic of minimum time after which this relay operates.It is inverse in the sense ,the tripping time will decrease as the magnitude of fault current increase. I have a test in oil and gase company as a electrical engineer after some days.please guide me the preparation for this test. Bus bars and isolators are rated for continuous power flow, that means they carry heavy currents which rises their temperature. Resolution:Knee point voltage is calculated for electrical Current transformers and is very important factor to choose a CT. Larger generators and transformers are required. With this,in case of unbalanced loading neutral will not be shifted.so that unbalanced voltages will not arise. LA is installed outside and the effect of lightning is grounded,where as surge arrestor installed inside panels comprising of resistors which consumes the energy and nullify the effect of surge. Define What is the function of anti-pumping in circuit breaker? Define stepper motor. Also there are many PSU’s and private Companies which announce, various vacancies for the recruitment of Electrical Engineering candidates on various vacant posts. uninterrupt power supply is mainly use for short time . Often the advantages of 3 phase motors, and other 3 phase equipment, make it worthwhile to convert single phase to 3 phase so that small and large consumers need not want to pay for the extra cost of a 3 phase service but may still wish to use 3 phase equipment. 40. ? With size of the equipment( transformer or alternator)and selection of relying system earthing will be further classified into directly earthed,Impedance earthing, resistive (NGRs) earthing. 89. What is inrush current? 13. what is meant by armature reaction? Why use the VCB at High Transmission System ? The two types of earthing are Familiar as Equipment earthing and system earthing. Explain what are inter-poles and why they are required in a dc machine. This assures Safety for the person who uses the electrical instrument. Secondly, don’t connect a capacitor across an alternator while it is picking up or without any other load. At first calculate the electrical current of the load, after that derate the electrical current considering derating factor(depending on site condition and laying of cable) after choose the cable size from cable catalog considering derating electrical current.After that measure the length of cable required from supply point of load to load poin. VCB’s can be used up to kv. Explain thin film resistors and wire-wound resistors step up or step down an unregulated dc input voltage to produce a regulated dc output voltage, invert the input dc voltage using usually a circuit such as the Cuk converter, and. DC or Static Resistance: DC resistance can be explained as the ratio of the dc-voltage across the diode to the direct current flowing through it. Phonographic appliances – Hysteresis motor. Electric traction means using the electric power for traction system (i.e. Hence, according to Faraday’s laws of electromagnetic induction, emf will be induced in both the windings. While an understanding of electrical engineering software is essential, more important is an understanding of the concepts and theories behind electrical engineering practices. These wires are made of materials such as Constantan and Manganin because of their high resistivity, and low temperature coefficients. Small units are now available for home use as well. That’s why the ac solenoid attract the plunger even though it’s terminals are interchanged. Why we do 2 types of earthing on transformer (ie:)body earthing & neutral earthing , what is function. alternator, can be steam turbines,or hydro turbines .When poles of the rotor moves under the armature Link is provided at a Neutral common point in the circuit from which various connection are taken for the individual control circuit and so it is given in a link form to withstand high Amps. 138. This effect is called as Corona effect, and it is considered as power loss. Desired results are obtained by either trimming the layer thickness or by cutting helical grooves of suitable pitch along its length. (anupnandi231@gmail.com) 23. Which type of motor is used in trains, what is the rating of supply used explain Working principal? 124. When the voltage difference is big it will damage the lamp and when the difference is smaller the lamp will glow depending on the type of lamp. In simple, synchronous generator supply’s both active and reactive power but asynchronous generator(induction generator) supply’s only active power and observe reactive power for magnetizing.This type of generators are used in windmills. 199. When DC supply is applied, due to low resistance, the current through lamp would be so high that it may damage the bulb element. 31. This resistance can be viewed by the output terminals and the energy sources can be removed by leaving the internal resistance behind. Can we measure over voltage and over current by measuring current only? This effect of supporting and opposing of main flux to armature flux is called armature reaction. Switch mode power converter can be used in the following 5 different ways. We can protect the equipment also. At the time of motor taking normal current (rated current)the speed of the motor is called rated speed. What is slip in an induction motor? Why electricity in India is in the multiples of 11 like 11kv, 22kv, 33kv ? 1 ton is equal to how many watts? As the coil moves into the influence of the next pole- pair, the current in it must reverse. What is meant by insulation voltage in cables? This reversal of current in a coil is called commutation. What happens if i connect a capacitor to a generator load? No complex pitch changing mechanism is needed. Disadvantages of low power factor: 181. b. The avalanche breakdown occurs in lightly doped junctions, which produce wide depletion layers. By using flux control method:in this method a rheostat is connected across the field winding to control the field current.so by changing the current the flux produced by the field winding can be changed, and since speed is inversely proportional to flux speed can be controlled .armature control method:in this method a rheostat is connected across armature wdg.by varying the resistance the value of resistive drop(IaRa)can be varied,and since speed is directly proportional to Eb-IaRa the speed can be controlled. JFET’s can only be operated in the depletion mode whereas MOSFET’s can be operated in either depletion or in enhancement mode. When voltage increases then current also increases then what is the need of over voltage relay and over current relay? The main advantage of using the star delta starter is reduction of current during the starting of the motor.Starting current is reduced to 3-4 times Of current of Direct online starting. Sir, its just an extra-ordinary piece of compilation. means according to ups VA it gives backup. 126. Resolution:It reduces the harmonics and it also reduces sparking and arching across the mechanical switch so that it reduces the voltage spike seen in a inductive load. 38. 122. We Know, VI= 540 V; V2=11KV or 11000 V; I1= 2334 Amps. Volt Amps with Reactive component. (p.u=actual value/base value). By means of an auxiliary motor: The rotor of a synchronous motor is rotated by auxiliary motor. c. From power stations, AC is produced so it is better to use AC then DC instead of converting it. Hence syn. Anyone can do that. Storage batteries are used for various purposes, some of the applications are mentioned below: 149. The reason that 4ma is chosen instead of 0 mA is for fail safe operation .For example- a pressure instrument gives output 4mA to indicate 0 psi, up to 20 mA to indicate 100 psi, or full scale. T -number of turns it is one type of synchronous motor which runs in steps in either direction instead of running in complete cycle.so, in automation parts it is used. (adsbygoogle = window.adsbygoogle || []).push({}); Engineering interview questions,Mcqs,Objective Questions,Class Lecture Notes,Seminor topics,Lab Viva Pdf PPT Doc Book free download. For example, Doyle suggests the following three questions: 1. When we connect the large capacitor bank in series ? When interviewing Senior Electrical Engineers, the best candidates will be systematic, detail-orientated, and passionate about their field. A two phase motor is often a motor with the the starting winding and the running winding have a phase split. 99. once the current passes through the tube the starter circuit will be out of part. Why transformer ratings are in kva? In a JFET, if the gate is forward-biased, excess-carrier injunction occurs and the gatecurrent is substantial. It is easy to maintain and change the voltage of AC electricity for transmission and distribution. By providing damper winding: Here, bar conductors are embedded in the outer periphery of the rotor poles and are short-circuited with the short-circuiting rings at both sides. 162. It is usually expressed as a percentage of Therefore, V=IaRa, Ia = V/Ra ,where Ra is very less like 0.01ohm.i.e, Ia will become enormously increased. What is the difference between electronic regulator and ordinary electrical rheostat regulator for fans? 84. what its purpose ? first the load on it must be made zero and then it can safely operated. 1.Why star delta starter is preferred with induction motor? How does Zener phenomenon differ from Avalanche breakdown? There are many ways to go into technical based question but that depends on what sort of industry or work field you are going to work. why? explain it? Explain the working principal of the circuit breaker? it also reduces over heating of transformers. it will help me for my grand viva in this semester. A variable frequency transformer is used to transmit electricity between two asynchronous alternating current domains. Refrigerators – Capacitor split phase motors. Resolution:ELCB is used to detect earth leakage fault. To minimize the current unbalance in the … Due to following reasons, AC systems are preferred over DC systems: • Reliability, Why did you decide to become an electrical engineer? 120. Top 10 senior electrical engineer interview questions and answers In this file, you can ref interview materials for senior electrical engineer such as types of interview questions, senior electrical engineer situational interview, senior electrical engineer behavioral interview… Generally capacitor gives infinite resistance to dc components(i.e., block the dc components). Electrical Engineering Interview Question And Answer-Basic Electrical Part 1 Electrical Engineering 200 Important Interview Questions With Answers PDF. now there is no change of supply causes choke voltage normalized and act as minimize the current. Sir, Please send me Electrical Engineering Interview Questions. The water is obtained in the boiler and the coal is burnt so that steam is obtained this steam is allowed to hit the turbine , the turbine which is coupled with the generator generates the electricity. DYN means Delta primary, Wye Secondry and the current is at o clock referred to the voltage. 48. What is the power factor of an alternator at no load? the voltage across the two terminals when RL is removed) and sum of load resistance and internal resistance of the network. really important for me.plz send me the question and answer. Resolution:The main function of an interposing current transformer is to balance the currents supplied to the relay where there would otherwise be an imbalance due to the ratios of the main current transformers. A lock-out relay is generally placed in line before or after the e-stop switch so the power can be shut off at one central location. Once the phase and neutral are connected in an ELCB, the current will flow through phase and that much current will have to return neutral so resultant current is zero. 1. Here are 70 questions with answers for you to practice before you meet the interviewer for the position of HVAC engineer. It is used in oil filled transformers, some types of high voltage capacitors, fluorescent lamp ballasts, and some types of high voltage switches and circuit breakers.

senior electrical engineer interview questions and answers pdf

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