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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
Can you use MCCB instead of fuse in a three phase connection?
Yes, three phase CDP (Central Distribution Panels) all use breakers to distribute the three phase supply voltage to their respective loads.
Is current present in everything of this physical universe?
No and (maybe) Yes.
No. Current is the movement of electric charge from one point to another under the influence of an electric potential difference. You can have charge without current.
(Maybe) Yes. You can also argue that charge is constantly moving at the atomic level as the electrons move between their various quantum states, but you can also (maybe) argue that this is not in response to an electric potential difference. You can also argue that, once you back out even a little bit and broaden your point of view, the net effect of that movement is zero.
The normal understanding of current is a daisy-chaining of electrons jumping from atom to atom at the valence shell level under the influence of a much more global electric potential.
An 'electrical degree' is 1/360th of one complete cycle of AC. This does not necessarily coincide with a 'mechanical degree', as it depends upon the design of the generator that produces the AC voltage. For a two-pole machine, the armature (rotating winding) must rotate 360 mechanical degrees in order to generate one complete cycle or 360 electrical degrees. A four-pole machine's armature, on the other hand, need only rotate through 180 mechanical degrees to generate one complete cycle or 360 electrical degrees.
On the other hand, you could be asking about a bachelor's degree in electrical engineering?!
How do you calculated kVA for 75kW motor?
It depends on the power factor. If the PF = 1, then you need 75kVA. In general, kVA needed = 75kW/PF.
How do you know which will is most current?
To determine which will is the most current, you should look for the document that explicitly revokes any previous wills, often through a clause stating it is the latest version. Additionally, check the dates on each will; the most recent date typically indicates the latest intentions of the testator. It's also important to verify if there are any codicils, which are amendments to a will that can change specific provisions without creating a new will. Finally, consulting with an attorney can provide clarity on the validity and status of the wills.
Why use 16mm cable for earthing?
A large cable for earthing is to allow for the possibility of a very large current which would melt a smaller one thus removing the protection it is supposed to provide.
How do you calculate negative phase sequence current?
4/4+4*4=20 is it correct by any means or not ? No this garbage has got nothing to do with negative phase sequence current in 3 phase electrical systems.
How the thickness of transmission lines reduce resistance?
The electrons in a wire travel mostly along the outside of the wire and hence the bigger the circumference the more surface area decreasing the resistance. An analogy is a vat of water with a valve at the bottom. Imagine that the water is a store of electrons creating a potential or voltage. If you only open the valve a little, the water will flow out of the vat slowly and hence the higher the resistance. As you open the valve further there is less resistance and more water can flow.
1 Will a single-phase induction motor start if only the running or the starting winding is excited?
With only one winding the motor needs to be spun manually to start and then it runs up in the same direction as it was spun. Without this it will just sit buzzing.
What is ment by restraining coil?
straining coils are winding that we uses to prevent the fault operation of relay
What is the frequency when there is an exactly 90 phase shift in gyrator circuit?
I'd have to know the inductance the gyrator is trying to simulate.
What is the difference between a 220 hot to hot and a 270 hot to ground?
Most residences have two 110-120V separate supplies that are combined to provide double the voltage or 220-240V. So you get 220V between hot of each 110V supply. Hence, hot to hot. A 270V system would typically not be in a residence, but a commercial establishment and is provided as a separate supply from a transformer. Hence the 270V is supplied hot to ground.
What is the difference between displacement and true power factor?
'Displacement power factor' is the technically-correct term used to describe the cosine of the phase angle (i.e. the angle by which the load current leads or lags the supply voltage) due to the reactance of a load. Usually, when we talk about the 'power factor' of a load, we mean 'displacement power factor'.
However, another type of power factor can exist in a circuit, due to the presence of harmonics in the current waveform, due to non-linear loads such as SCR rectifiers. This type of power factor is temed 'distortion power factor', and may be corrected using filters.
So, the terms 'displacement' and 'distortion' are used whenever it is necessary to clarify these different types of power factor.
Without a load the secondary current is zero, by definition.
Fill factor is the ratio (or the difference) between the actual output of a solar cell or panel, and its theoretical output (which can be about 30%higher).
Why in open circuit test Req plus jXeq is neglected?
In an open circuit test, the impedance of the test circuit is dominated by the high reactance of the winding inductance, which leads to negligible current flow. As a result, the equivalent resistance (Req) and reactance (jXeq) of the transformer or machine being tested have minimal impact on the measurements. Consequently, the test primarily reflects the core losses and magnetizing reactance, allowing us to focus on those parameters without interference from the impedance. Thus, Req + jXeq is often neglected in open circuit tests.
How do you splice a ground wire?
Strip the wires back about 3/4" and then using lineman's pliers twist the wires together about 2 turns. Tighten a wire nut securely to the connection. Then tape the splice securely with electrical tape.
One cycle of the signal lasts 0.029 milli seconds.What is the frequency in KHz?
frequency means number of cycles per second.
here 1 cycle takes .029 mili sec or .000029 sec so the number of cycles in 1 sec is
1/.000029 = 34482.75 Hz = 34.5 KHz
15/600 * 200
What are all the transformations like reflection?
scale, rotate, reflect, Translate(move identical image), Affine Transformation( altering the perspective from which you view the image)
Vrms=Vm/1.414................... from this u can find Vm.....magnitude of voltage.
Why potential difference across open circuit is more than in closed circuit?
In a closed circuit there is a potential drop due to resistance of wires and battery (internal).
AnswerWhen the circuit is closed, the resulting current not only flows through the external circuit, but through the source (battery, generator, transformer, etc.) itself. All sources have an internal resistance, which causes an internal voltage drop, slightly reducing the voltage across the terminals. The larger the current, the larger the internal voltage drop, and the lower the terminal voltage.
When the circuit is open, no current flows. So there is no internal voltage drop, and the full voltage appears across the source's terminals.
The 'open-circuit voltage' is actually the electromotive force provided by the source.
What is Faraday law of a DC generator?
Faraday's law : If a "conductor" is placed in a "magnetic field" the movement in either conductor or field produces an induced emf in the conductor.
In generator the produced torque will be in AC(alternating current) so commutator or slip rings is used to produce unidirectional torque required for production of Direct Current.
Basically by Faraday law the produced torque will be always bidirectional,
for alternator the bidirectional torque can be used directly.
for DC generator the unidirectional torque is needed to produce Direct Current.
A kilovolt (kV, not 'kv') is the SI unit for potential and potential difference (voltage), whereas the kilovolt ampere (kV.A, not'kva') is the unit for apparent power. These are quite different quantities, so you cannot change one to another -if that is what you are asking.
Voltage from the trigger coils activates what?
Voltage from the trigger coils activates the ignition system in engines, particularly in ignition coils or distributors. This voltage generates a spark that ignites the air-fuel mixture in the engine's cylinders, enabling combustion. In some applications, it can also trigger other components, such as relays or control modules, to initiate various electrical functions in the vehicle.
