electrical interview questions and answers in pdf

Electrical interview questions and answers in pdf

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Published: 10.04.2021


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In today post, we will be sharing the frequently asked electrical engineering interview questions and answers related to electrical engineering. Electrical engineering deals with high voltage especially AC above the range of or V. When manufacturers design a transformer, they have no idea which kind of load will be connected to the transformer.


In today post, we will be sharing the frequently asked electrical engineering interview questions and answers related to electrical engineering. Electrical engineering deals with high voltage especially AC above the range of or V. When manufacturers design a transformer, they have no idea which kind of load will be connected to the transformer. The output of real power may vary depending on the power factor.

A real transformer has the following losses;. The losses occur due to the current flow through the windings that causes resistive heating of the conductors. There are two types of core or iron losses. These losses occur due to the magnetic field reversal. The losses due to the current generated inside the core.

The eddy current causes the resistive heating of the core. Various other losses include:. Transformer Efficiency:. The efficiency of the transformer is given by the output power divided by the input power. Some of the input power is wasted in internal losses of the transformer.

All Day Efficiency:. The ratio of energy delivered in Kilo Watt-Hour kWh to the energy input in kWh of the transformer for 24 hours is called all-day efficiency. Condition for Maximum Efficiency:. The voltage regulation of a transformer is the percentage change in the secondary voltage from no load to full load condition. Ideally, the secondary voltage remains the same throughout the load, in which case the voltage regulation is zero.

But practically it varies with the power factor of the load. Under the open secondary condition, the primary current becomes the magnetizing current that generates a very high secondary voltage that can damage the insulation as well as can pose danger to personnel. The total impedance of the circuit can be used to identify the circuit.

If the imaginary part of the total impedance is positive, then it is an inductive circuit. It the imaginary part is negative, and then it is a capacitive circuit.

If it is zero then the circuit is purely resistive. The current lags the voltage in an inductive circuit while the current leads the voltage in a capacitive circuit. A unilateral is a type of circuit whose properties change with the direction of current flow or the voltage.

The properties of a bilateral circuit do not change with changing the current direction or supply voltage. The circuit parameter such as frequency, resistance, inductance, capacitance, etc. Ohm law is not applicable to a unilateral circuit or a non-linear circuit. Thus it is not applicable in such a circuit. Also, the temperature must remain constant. What is the maximum power transfer theorem? It mentions the condition for maximum power transfer from source to load. Reactive Power : The powers that continuously bounce back and forth between source and load is known as reactive power.

If the current leads the voltage, it causes a leading power factor. If the current lags voltage the power factor is lagging. Most loads are inductive that causes a lagging power factor. Thus these following methods are used for p. It is an over-excited synchronous motor with no load that also provides a leading power factor. Phase advancer is used to improve the power factor of induction motor in industries. The reason for improving the power factors are stated below;.

F and the rating has been mentioned in kW or HP on Motor. In more clear words, Motor only consumes active power and provides mechanical power in HP or kW at the motor shaft and that is the reason for motor rating in Watts.

Motor Starter is a device that connects in series with the motor to decrease the starting current that could damage the windings in normal conditions and gradually increase current after starting the motor in other words start or stop the motor and provide overload protection.

A magnetic starter is a device designed to provide a safe starting method to electric motors with a heavy load. It includes a contactor as an essential component, while also providing power-cutoff, under-voltage, and overload protection. A battery converts chemical energy into electrical energy which is the charge stored inside the chemicals.

The amount of current it can supply for a said time thus Ampere-hour Ah is the unit for its rating. While the batteries supply direct current which has no phase or frequency thus there is no concept of P. F or reactive power, thus no need for expressing it in VA and its rated in Ah. The primary cell is a non-rechargeable battery that cannot be recharged by any means. The secondary cell is a rechargeable battery that can be recharged several hundreds of times depends on its life cycle.

Their initial cost is expensive compared to the primary cell. They are mostly used in cellphones, vehicles, generators, etc. We have discussed both in details in different types of batteries. Circuit Breaker. It can also manually break the circuit. An isolator is a mechanical switch used for isolating or disconnecting power supply in substations.

It is an off-load device i. It has a high current rating of around Amps, where its interrupting ratings are between 10K to k Amps. Also, its tripping characteristics can be adjusted. They are used in industries.

The key difference between them is that the generator has a stationary magnetic field i. So the stationary part of the alternator is phase conductors. Capacitance: capacitance is the ability of a component to store charge between two plates when there is a potential difference applied. Inductance: inductance is the ability of a conductor to resist or oppose any change in the current.

The current generates a magnetic field whose strength varies with the current. The different colors of the wires are used for phase indication purposes. The color code may differ around the world but usually, the earth wire remains the same i. Usually, the voltage drop in cables should not be greater then 2. The cable charts provide this info such as voltage-drop per meter, current capacity, cable size, etc.

The main two types of semiconductors are;. Mainly the transistor can be used for two reasons. The current has a linear inverse relation with the resistance. Thus, doubling the resistance will decrease the current by half. There are two reasons for increasing the current;. An electrical outlet has two wires i. The Reverse polarity means that the neutral wire is connected to the terminal where the hot wire is supposed to be.

It can be easily fixed by swapping the wire. A rectifier is an electronic circuit that converts the alternating current into a direct current. The types of rectifiers are as follows;. It is a special type of diode that not only conducts current in forward but also in reverse direction once the Zener voltage is reached. It is used in reverse bias to maintain a constant voltage over a range of currents.

It is a safety device used as a voltage regulator or to protect other components from overvoltage. Analog circuit can process an analog input signal that has continuously varying voltage. An analog circuit can convert an analog signal into a digital signal. Digital circuit can only process a digital signal i. The Laser diode converts electrical energy into light energy just like an LED but it creates coherent light.

They are used in optical communication, pointer, printer, etc. The fuse is made of a metal wire called fuse link or element that melts when the current exceeds its limit. The circuit breaker is an electromechanical switch that opens the circuit during overcurrent or short-circuits.

Answer :. It is used for creating high voltage using a low voltage source. Its outer strands are made of highly pure aluminum to have better conductivity while the center strands from steel to increase the tensile strength of the cable.

It is used for overhead transmission lines. A circuit breaker breaks the circuit by opening the contact terminals. During the opening, an arc is generated between the terminals that can be quenched using various mediums.

In VCB, the medium for arc quenching is a vacuum.

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Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website. See our User Agreement and Privacy Policy. See our Privacy Policy and User Agreement for details. Published on Apr 2, Top 92 electrical interview questions and answers pdf free pdf download ebook.

In electrical engineering, there are a lot of jobs like control electrical engineer, assistant engineer, trainee mechanical, room operator, junior engineer maintenance, electrical design engineer, etc. An electrical engineering company asks a lot of interview questions in the technical round. So one should brush up and update their technical knowledge by knowing the latest updates in the electrical field by knowing Interview Questions on Electrical. Here we have listed some of the interview questions on electrical engineering with answers that may be asked in a job interview. The following interview questions on electrical with answers are very helpful for electrical students to clear the technical round in an interview. These electrical interview questions are collected from different fields in electrical engineering.

Name the types of motors used in vacuum cleaners, phonographic appliances, vending machines, refrigerators, rolling mills, lathes, power factor improvement and cranes. Explain the process of commutation in a dc machine. Explain what are inter-poles and why they are required in a dc machine. Define the following terms:- Reliability, Maximum demand, Reserve-generating capacity, Availability operational. Explain the terms real power, apparent power and reactive power for ac circuits and also the units used.

ELECTRICAL INTERVIEW QUESTIONS AND ANSWERS. Visit stpetersnt.org more resources. 1. What happens if I connect a capacitor to a generator load?

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While not always the case, how a candidate performed while attaining a degree or a doctorate is generally a good indication of how they will perform on the job. A candidate's response will also help you determine strengths and weaknesses. What to look for in an answer:. I also did well in linear algebra, and I am most proud of the grade I earned in convex optimization.

What is electricity? Ans : Electricity is a general term used for all phenomena caused by electric charge whether static or in motion. Ans : There are two types, 1 static Electricity and 2 Current Electricity. Ans : Static electricity means electricity at rest in contradistinction to dynamic or current electricity the effects of which are purely due to the electrostatic field produced by the charge.

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  • Amarilia O. 18.04.2021 at 18:15

    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.


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