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Anna University Previous Year Questions on Transformers In this post, we collected some of the questions on transformers (semester-III)  asked in anna university previous year semester exams. We are sure that they will help you to prepare for your technical interview. [1] Why transformers rated in KVA instead of KW? The copper loss (I2R) in the transformer depends on the current I through the winding while the iron or core loss depends on the voltage V as frequency of operation is constant. None of these losses depend on the power factor (cosφ) of the load. Hence losses decide the temperature rise and hence the rating of the transformer. As losses depends on V and I only, the rating of the transformer is specified as a product of these two parameters VxI. Thus the transformer rating is in kVA and not in kW. [2] Why is the efficiency of transformers more than that of other rotating machines? There are no moving parts in transformer hence the friction and mechanical losses are absent...

Frequently Asked Interview Questions on Alternators In this post we had given few Alternators related Interview questions with solutions. We believe that it will be helpful for your interview preparation. Please leave your comments in comments section. [Q] What is meant by synchronising the alternators? The process of connecting two or more alternators in parallel for supplying a common load is called synchronising. [Q] What are the conditions to be satisfied for proper synchronising of alternators? (i) The terminal voltage of the incoming alternator must be the same as bus-bar voltage. (ii) The speed of the incoming alternator must be such that its frequency equals to the bus-bar frequency (iii) The phase sequence of the incoming alternator must be the same as that of the other alternators or busbars. [Q] What are the advantages of Parallel operation of alternators? (i) It ensures continuity of power supply to consumers in case of breakdown of an alternator in an generation station. (...

Basic Electrical Engineering Interview Questions Answers 1 [Q] Define Power and Energy? The rate at which work is done in an electric circuit is known as Electric power. Power = Voltage X Current The basic unit for electric power is Watts The instrument used to measure the power is known as watt meter. The total amount of work done in an electric circuit is called as electric energy.  Energy = Power X Time the basic unit is Joule or watt-sec The practical unit is Kilo watt-hour The instrument used to measure the energy is known as Energy meter. [ Like this you have to explain elaborately in the interviews. The interviewer will expect detailed answer from the candidate. If he feels that you are deviating too much, then he will stop you and ask another question. Please don't answer in one line. Add related points where ever possible] [Q] In our house are we monitoring/measuring power or energy? Energy. It is done by energy meter. [Q] what is meant by cycle in ac waveform? what i...

Basic Interview Questions on Induction Motors: [Q] How does the Induction motor work? (OR) Why does the Rotor rotate? When the 3 phase stator windings are fed by 3 phase supply, a magnetic flux of constant magnitude which is rotating at synchronous speed is set up.  The flux passes through the air-gap and sweeps past the rotor surface  thus it cuts the rotor conductors.  Due to the relative speed between the rotating flux and the stationary rotor conductors, an emf is induced in the stationary rotor conductors as per the Faraday's laws of electromagnetic induction. The frequency of the induced emf is the same as the supply frequency. Its magnitude is proportional to the relative velocity between the flux and the conductors. Its direction will be as per Fleming's right hand rule. Since the rotor conductors form a closed circuit the rotor current is produced. This current's direction will oppose the very cause producing it ( as per Len's law) Here the cause is the...

Power Electronics Technical Interview Questions asked in Ametek Aerospace                One of our friend shared his interview experience. The position is for Senior Power Electronics Engineer with 5 year experience. We believe that it will be usefull for your interview preparation... The following questins were asked in the interview... [1]   How to choose a micro controller? [2]  What is the difference between a LDO and a Linear regulator? [3]  What is the difference between I2C and SPI? [4]  What is the difference between logic analyzer and a oscilloscope? [5]  On what crises do we select components/Selection of a capacitor? [6] Opamps/ADC/DAC how do you interface them externally /which ADC/DAC you have been used  and why do you selected them/resolution ? [7]  What are usages and issues with J-Tag debugger? [8]  Any experience in Automation? [9]  Emi/Emc ...

These questions were asked in TCS campus interview at Govt. College of Engineering, Tirunelveli. 1. Tell me about yourself 2. About TCS 3. As a electrical engineer, why software company 4. Draw AND gate 5. what is difference between latch and flipflop A flip-flop continuously checks its inputs and correspondingly changes its output only at times determined by clocking signal. A latch is a device which continuously checks all its input and correspondingly changes its output, independent of the determined by clocking signal. 6. Types of flipflop: There are basically four main types of  flip-flops: SR, D, JK, and T. 7. Do you know C 8. Are you willing to travel for onsite ................................................................................................................................... Thanks for reading. Please leave your comments below.  Please share your interview experiences. We will post it with answers which will be useful for our readers.

These questions are asked in the technical interview conducted in Goodrich, Bangalore for the post of Design Engineer with 2 year experience. As it is for the experienced engineers, we would have to explain as much as possible about the topic. We did not answer the non technical questions here. A1: Question about previous exp. A2: Question about currently working project. [1] Explain the amplifier operation of OP-AMP? The golden rules of OP-AMP are: 1. Vout = A. Delta Vin  [ A = Gain, Delta Vin = V+  -  V-] 2. V--  < Vout  < V++ 3. Zout = 0    ,      Zin+ = Zin- = Infinity The opamp will work as inverting amplifier and non- inverting amplifier based on the supply applied to its terminals. Non Inverting Amplifier: Inverting Amplifier: [2]Interrupted and Asked to derive the equation... Current i =  (Vin-Vout) / (Rin+Rf)               =( Vin - Vx)/Rin = (Vout - Vx)/Rf Vx = virtual grou...