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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 wave form of clipping circuit?
As a sinusoidal signal is clipped the waveform approaches a square wave.
What is the difference between a star-delta starter and a DOL starter?
At least two types of 3-phase electric motor starter are available: Direct-On-Line (DOL) and Star-Delta.
For more information about how they work, and the differences between them, see the answers to the Related Questions shown below.
Why does your 1986 Landcruiser not start after the motor is warm?
Is it petrol or diesel? if it is petrol then the spark plugs may need replacing or the valves are not operating properly at higher temperatures. If in doubt get it checked by a qualified mechanic.
Another possibility is the anti-vaporlock fan is not working. This is a fan on the left side of the engine compartment in FJ60 and FJ62 gasoline models. This can be a fan failure, or the thermal switch. If you don't hear the fan running when the engine is switched off, this is the most likely cause. Opening the hood to allow cooling will get you by.
Why use a step down trans former when the lower voltage is available?
The secondary winding of a double wound transformer is 'floating' in that it is not referenced to any other part of the circuit. You choose how to reference it. You cannot accomplish this without a transformer.
What is frequency dead band in turbine control system?
it is range of frequency variation for which governor does not take any proportional corrective action.
A rather strange question, as most transformers are installed by trained individuals who wouldn't be using this forum for help. However, it will be necessary to refer to the manufacturer's specifications for that specific transformer in order to determine how to achieve the desired output.
What AC motor is used in an escalator?
we can either use dc series motor or induction machine ,but dc supply is not easily available so we use induction motor ,
How many 120VAC single-phase output receptacles does a 25kW Power Distribution panel have?
If you are referring to the 25KW Power Distribution Panel used by the military, NSN: 6110-01-244-3209, there are four 120VAC, 20A circuit breakers and four corresponding twist lock receptacles.
starting current of 315 kw motor in start delta 2.5 time for single sec.
if your cable lingth 130 meter u can use 150mm2 (3 cable per phase)
150mm2 single cable current 292 Amp voltage drop 0.28/meters so u can use breaker 1000 Amp and set Im time (for starting current) setting avalible in breaker.
Is 4 kv and 30 ma be lethal from dry hand to hand?
30 ma will not hurt you but 4 kv or 4000 volts will certainly kill you for it will push far more than 30 ma through your body-wet or dry!
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Taking any amount of AC voltage from hand to hand is dangerous. This is because the path the voltage takes is across the chest in the location of your heart. Small voltages can stop the heart from beating.
Milliamps are dangerous and will hurt you as shown below;
Less than 1/2 milliamp no sensation
1/2 to 2 milliamps Threshold of perception
2 to 10 milliamps muscular contraction
5 to 25 milliamps painful shock (may not be able to let go)
Over 25 milliamps Could be violent muscular contraction
50 to 100 milliamps Ventricular fibrillation
over 100 paralysis of breathing.
1.8 amps of current passed through. I'm assuming you meant electrical charge however, in which case 1.8 A * 6 s = 10.8 C of charge passed through, where C stands for Coulombs. That is equivalent to roughly 6.74 X 1019 electrons passing through.
A GFCI can not be used on a three wire branch circuit. It has to be on a single two wire circuit.
What is economic dispatch in electrical power system?
The operation of generation facilities to produce energy at the lowest cost to reliably serve consumers, recognizing any operational limits of generation and transmission facilities
Why do we use additional rcd for earth fault protection?
A 'standard' fuse requires the current to reach a certain level before it blows. This could theoretically cause a user to suffer an electric shock before the fuse 'blows'. An RCD device monitors the current in the circuit and trips a re-settable switch when the current exceeds a safe level. RCD devices react much quicker than the old-fashioned fuses.
What length of a copper wire 0.800-melimmeter in diameter has a resistance of 100 ohm?
Work it out for yourself. The equation you will need to use is:
resistance = resistivity x (cross-sectional area / length)
Manipulate the equation to make 'length' the subject, and use 17.25 x 10-9 ohm metres as the value of resistivity.
Can items in a series circuit be in any order?
Yes. The arrangement doesn't change the current through
the circuit, or the voltage acrosss any individual component.
The letters, 'r-y-b', represent the colours 'red-yellow-blue', which are used to identify each of the three lines of a three-phase system. This remains the current UK standard for electricity transmission/distribution systems, although for residential/commercial wiring, the EU colours 'brown-black-grey' have been adopted.
Alternatives include 'r-s-t', 'a-b-c', '1-2-3', etc.
=== === This answer assumes the wire is properly insulated along its length so that it does not have any shorted turns if it is wrapped around a core made of a good insulator such as wood or plastic. Whether or not it is wound into a coil the resistance of a piece of copper wire depends on how long and thin it is. The thinner and longer the wire, the higher the resistance it will have and the less current it will draw from the power source.
A very short piece of thick wire will have such a low resistance it will take so much current that it will behave just like a short circuit. (Whether it is insulated or coiled even a little bit will make no difference.)
If a sufficiently long length of insulated wire is made into a coil it will act as an inductor. If it is wound around a cardboard or wooden core containing a piece of iron, the iron would make the coil have a much higher inductance than for just air.
