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Electrical Engineering
Electrical engineering is a field of engineering that deals with the study and application of electricity, electronics and electromagnetism.
23,056 Questions
What is function of load break switch?
A load break switch is a disconnect switch that has been designed to provide making or breaking of specified currents. This is accomplished by addition of equipment that increases the operating speed of the disconnect switch blade and the addition of some type of equipment to alter the arcing phenomena and allow the safe interruption of the arc resulting when switching load currents.
Disconnect switches can be supplied with equipment to provide a limited load switching capability. Arcing horns, whips, and spring actuators are typical at lower voltages. These switches are used to de-energize or energize a circuit that possesses some limited amount of magnetic or capacitive current, such as transformer exciting current or line charging currents.
An air switch can be modified to include a series interrupter (typically vacuum or SF6) for higher voltage and current interrupting levels. These interrupters increase the load break capability of the disconnect switch and can be applied for switching load or fault currents of the associated equipment.
What is the difference between thermal power plant and captive thermal power plant?
The basis of differentiation is end user. A thermal power plant produces electricity to sell the same to different end users through grid. But, in case of a captive thermal power plant generation of electricity generally is to meet the demand of power by the parent industry. For e.g. an Alumunium smelter plant requires huge quntity of elctric energy to operate. To secure undisrupted source of energy it may set up its own power plant which in turn can be termed as the captive power plant. But, in certain cases excess electricity can be sold to the market.
M (usually as a capital) million. As "m" strictly is a thousandth (as in mm=millimetre), but I've never seen it for that purpose.
Why perform transformer oil colour test?
Transformer oils are subject to electrical and mechanical stresses while a transformer is in operation. In addition there are contaminations caused due to chemical interactions with windings and other solid insulations, catalyzed by high operating temperature. As a result the original chemical properties of transformer oil changes gradually, rendering it ineffective for its intended purpose after many years. Hence this oil has to be periodically tested to ascertain its basic electrical properties, and make sure it is suitable for further use or necessary actions like filtration/regeneration has to be done.
What are the advantages and disadvantages of unity power factor?
There is no disadvantage of unity power factor, because at unity power factor all the electrical power is efficiently utilized by the the load, and at lagging power factor some power is lost in the load's magneticfield.
Why the load must be removed when to conduct the insulation and resistance testing?
explain why all the load must be removed when to conduct the insulation and resistance testing
What is PU in electrical engineering?
"PU" can stand for multiple things, depending on what part of "electrical engineering" you're interested in. In the power world (power generation, transmission, distribution) "PU" may stand for per unit, or pickup if related to protective equipment like relays.
How much full load ampere in 2 horse power compressor?
It depends on the voltage of the compressor. Two horse power (electric) is 1492 watts, but watts are volts times amps, so you need to know the voltage. Since the motor is an inductive load, you will also need to know the power factor, so as to compensate for true vs apparent power.
What is the resistance of the circuit if the voltage is 230 volts and the current flowing is 5 amps?
The resistance of the circuit will be 46 ohms
What is meant by resonance in LCR circuit?
a circuit in which inductance L,capacitance C and resistance R are connected in series and the circuit admits maximumum current corresponding to a given frequency of a.c.
Another Answer
In the case of a series circuit, resonance occurs when its inductive reactance is exactly equal to its capacitive reactance. As the vector sum of these two quantities will then be zero, the only opposition to current will be resistance and, so, maximum current will flow through the circuit when resonance occurs. ALL circuits can be made to resonate at what is called their 'resonant frequency' because, as frequency increases, the inductive reactance increases but capacitive reactance falls -so, at some point the two will equal each other, and resonance will occur.
In my view resonance means - the condition that exists when the inductive reactance and the capacitive reactance are of equal magnitude, causing electrical energy to oscillate between the magnetic field of the inductor and the electric field of the capacitor.
Which type of transformer is used in sonometer?
A sonometer is used to determine the frequency of alternating current. A step down transformer is used for the determination of frequency of A.C. because the voltage of the A.C. mains is 220V, which is dangerous. The step down transformer reduces this voltage to 6 volts.
Why buchholz relay is used in transformer have ratings more than 750kva?
Buchholz Relay is a special type of relay and its only used in transformers, and the main use of this relay is transmission and distribution system
AnswerA Buchholz relay is used between a transformer and its expansion tank. So they are only used (1) where there is an expansion tank and, (2) in substations, where the associated protection relays can be installed.
Do powerline neutral wires have to be insulated?
Not always. Some times the neutral wire will be isolated from ground by small insulators that will flash over in the event of a lightning strike, but typically it's been my experience that the neutral wire will be bare conductor, and grounded multiple times through structure grounds on high voltage transmission lines.
Is the plot of current versus frequency symmetrical about the resonant frequency in LRC circuit?
The plot of current vs. frequency is not symmetric because the equations for inductive reactance and capacitive reactance are not symmetric. One is linear and the other is inverse.
Is voltage and current are proportional?
Yes, due to ohms law. Current, resistance and voltage are all directly proportional. V=IR; I=V/R; & R=V/I
What does MD stand for in electrical terms?
Md stands for maximum demand.max dem =connected load /diversity factor.diversity factors min value -1.
What is meant by ZEROTOX cables?
ZEROTOX cables is a range of non-halogenated low smoke and fume, flame retardant cables. (In short non-toxic cable).
When PVC cables are involved in a fire they produce dense black smoke and hydrochloric acid gas (HCI) fumes, which are both toxic and highly corrosive.
What happens if someone touches a high voltage wire?
If they are grounded they get an electric shock or electrocuted. If they are not grounded or in simultaneous contact with the neutral wire, nothing. That's why birds can sit on a high voltage wire and survive; they are not grounded.
What is parallel path in dc machine?
This describes the way the machine's armature conductors are connected relative to each other and to the number of poles. The two basic ways of connecting these conductors are called 'lap' and 'wave', but it gets more complicated, because these, in turn, can be connected 'simplex', 'duplex', 'triplex', etc.
For lap windings, if there are p poles, then for:
- simplex:
p
- duplex:
2p
- triplex:
3p
- etc.
For wave windings, the number of parallel paths are:
- simplex:
1 x 2
- duplex:
2 x 2
- triplex:
3x 2
- etc.
3p =3 x 6 = 18 parallel paths.
