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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 the size breaker per phase 200kva generator?
if you have 200 kva so it's 160 KW then ,you need 400 A MCCB and setting at 0.9 and use cable 4c.185 mm2 if the SMDB is nearby and all this will be change according to the ambient temperature and the electrical code used in your area
How much does a wind farm cost to build?
Considering the fact that a 500MW coal-fired plant can cost upwards of $1 billion just for land acquisition and construction (not considering operational and maintenance costs or fuel costs), a wind farm with equivalent energy output, zero emissions and no-cost fuel (wind) comes in at about $600 million.
'Equivalent energy output' is incorrect. The original author is confusing 'installed capacity' - the power it could generate under ideal conditions - with output. This is a very important distinction.
For example, if you have 500MW of coal capacity and 500 MW of wind capacity, as long as you have optimal fuel for each system, they will output the same amount. In the case of coal, the operator can control the fuel supply (mostly) and run at any percentage of peak capacity for as long as is desired, up to 100% of the time. For wind, the operator is at the mercy of how much and how fast the wind blows and can only operate at peak capacity when conditions are perfect, which is less than 15% of the time. The concept is called 'capacity factor'.
Why is gain affected when the bypass capacitor is open?
Applied input signal at the base of the amplifier appears across the emitter resistor (RE) due to inter electrode capacitance so it should be bypassed the emitter resistor (RE) through the bypass capacitor (CB). unbypassed signal will be amplified (common emitter amplifier) and reverse back from the emitter to the collector through the base, amplified signal from the emitter to the collector (common emitter amplifier) is 1800 out of phase to the amplified signal from the base to the collector (common base amplifier), so reduced the gain.
Where ac voltage controllers are used?
AC voltage controllers are used for controlling the speed of universal motor or induction motor by changing the firing angle :) -vinodh gav
What precautions to be taken when working with Transformer?
Frist putt of the main incomer HT side then Rack out the breaker and put the LOTO after that Discharge the cable Both side (HT/LT).
What is the difference between single pole mcb and double pole mcb?
A single pole circuit breaker can protect one hot wire to a given load where as a two pole circuit breaker can protect two hot wires to a given load. In the North American system this would equate to 120 volts on a single pole circuit breaker and 240 volts on a two pole circuit breaker.
How can one convert 180 VDC to 24 VDC?
If you are talking about alternating current you would use a step down transformer with the primary being 240 volts and the secondary being 24 volts.
The total resistance would be 40 ohm.
Which voltmeter will used for measuring 50kv dc?
Any standard voltmeter but however the voltage to be measured must be stepped down to a safe value using a Potential transformer.
What classes to take in high school to become an electrical engineer?
None. An electrical engineer is educated by an ABET accredited university. However, a solid high school educational background in math and physics may help one to master electrical engineering in college.
What is the difference between an open delta and an open wye connection?
An open delta connection is a delta connection with one phase removed, but still supplied with three line conductors. An open wye is a wye connection with one phase removed, supplying a three line conductors and a neutral conductor.
An open-delta/open-wye is a method of providing a reduced-load three-phase supply using just two single-phase transformers, rather than the preferred method of using three single-phase transformers.
Why brushes are made of only carbon graphite in dc machines?
The brushes are made up of carbon because it has low friction as compare to other materials and cheaply also, but carbon has high resistance due to which output can vary. So we mix carbon with copper metal to reduce resistance.
Note that we cannot use copper only for brushes because it creates more friction with commutator.
What is the SI unit of charge?
coulomb
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Coulomb (symbol C) is a derived unit for electrical charge in SI; the base units are:
1 C = A x s
So, the coulomb is the electrical charge transported by an ampere in one second.
How rotar rotates of DC motor?
The rotor in a DC motor rotates because the magnetic field in either the rotor or the stator is constantly changing. If it is a brush type DC motor, then the rotor field changes as the rotor moves to a new position on the commutator. If it is a brush-less type DC motor, then there is some circuitry associated with the stator that changes the stator field.
What is the purpose of a contactor and a relay?
to protect or to calculate the operating conditions of an electrical system and to camand circuitbreaker to trip in any fault detection.relay is the one which detects the abnormal condition of the circuit and signals the circuit breaker to trip(open).....
Is voltage measured between two points?
Yes. Voltage is the electric potential difference between two points. Always.
Volts is an SI derived unit representing the potential across a conductor that causes a current of one ampere to flow when one watt of power is being dissipated in that conductor. As such, it also means joules per coulomb.
What causes the axle to spin in an electric motor?
Switching the field voltage to the coils forces the magnets to move.
Why can't human beings sit safely on electric power lines?
Theoretically, human beings can sit safely on an individual overhead line conductor, providing no part of their body comes into contact with another conductor or the earth. In practise, of course, it's another story as it's highly improbable that anyone could approach a high-voltage line in the first place!
What is clearence between phase to phase in 33 kv?
The clearance between 33-kV line (not 'phase'!) conductors depends on whether they are rigid (e.g. busbars) or can move (e.g. overhead lines); whether they are insulated or in air; etc.. So there are several 'clearance' distances. All are published on the internet -so you can do a search to find out for yourself.
How much current does 300 sq mm cable carry?
A 228 sq mm conductor equates to 450 MCM. A conductor of 450 MCM is not a standard AWG wire size. A standard 400 MCM will carry 380 amps. A standard 500 MCM will carry 430 amps. Difference between 400 and 500 MCM amperage's is 50 amps. Transposing between the two amperage's of 50 amps will be 380 + 25 = 405 or 430 - 25 = 405 amps. This is a very rough calculated answer for the question.
Which meter measures the potential difference in the circuit?
A voltmeter measures the potential difference between two points,
whether or not the two points are in the same circuit.
What is the importance of ammeter?
An ammeter measures current, an important variable in electronics.
How do you calculate copper wire resistance?
if we know resistivity of copper i.e is very small (1.68×10−8)
transposing the definition to make resistance the subject (Pouillet's law):
R is the electrical resistance of a uniform specimen of the material (measured in ohms, Ω) is the length of the piece of material (measured in metres, m)A is the cross-sectional area of the specimen (measured in square metres, m²).
