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A small amount of electricity can be generated without DC excitation due to the phenomenon of electromagnetic induction. When a conductor moves through a magnetic field, or when the magnetic field around a stationary conductor changes, an electromotive force (EMF) is induced. This can happen in various systems, such as in generators or even through residual magnetism in the system, allowing for the generation of small amounts of voltage without the need for external DC excitation.
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Where does the voltage that is necessary for field excitation on the rotor originates from?
The excitation current is provided by a small self-excited pilot generator, attached to the same shaft as the alternator's rotor.
Why small voltage is built up immediately in rotating shunt machine even without field excitation?
In a rotating shunt machine, a small voltage can be generated even without field excitation due to residual magnetism in the rotor. This residual magnetism creates a weak magnetic field, which induces a small voltage in the armature windings as the rotor spins. Additionally, the armature reaction can enhance this effect slightly, allowing for voltage to build up immediately upon rotation. The small voltage may not be sufficient for practical use but demonstrates the machine's inherent capacity to generate some electrical output.
Can you amplify the electricity when you have only very small power supply or any mechanism for it?
you really can't amplify electricity. You can amplify sound but that is different. You can change the voltage but the actual power will not change because as voltage is raised current is reduced. you can only increase power by increasing the mechanical input to a generator which will increase the electrical power as well. The conservation on energy says that power cannot just be created. It needs to come from some where either mechanical or thermal. Following the conservation of energy, you can convert kinetic energy into electric energy using a (relatively) small amount of electricity - this is what a synchronous generator does. A small amount of electricity is used to create a magnetic field; the stronger this field, the more energy can be "pushed out" of the generator; this energy must come from the kinetic energy stored in the spinning machine. In this way, a synchronous generator can be thought of as an electricity "amplifier".
How residual magnetism present inside the self excited generator?
Residual magnetism in a self-excited generator refers to the small amount of magnetism that remains in the magnetic core after the generator has been de-energized. This residual magnetism is crucial for the initial excitation of the generator because it provides the necessary magnetic field to induce voltage when the generator is started. As the rotor turns, the residual magnetism induces a small voltage in the stator windings, which, when connected to the field windings, enhances the magnetic field and leads to self-excitation, allowing the generator to generate power. Without sufficient residual magnetism, the generator may fail to start or produce voltage.
Most of the electricity used in the world is generated by?
The majority of electricity is generated from fossil fuels, coal, oil and gas. Fossil fuels need to be replaced by other sources as the resources we rely on are becoming more scarce. Increasingly, renewable energy sources are being used such as wind, solar, hydro-electric, tidal but these represent a small percentage of the total generation. Nuclear power has had its share of problems but in the twenty first century, it is making a comeback. Better controlled and safer than early nuclear power stations, new stations are being constructed.
Do telephones use a small amount of electricity?
If your telephone came with a charger then yes it uses a small amount of electricity. This is what the charger does, it replenishes the electricity that the telephone used while not connected to the charger.
How does electricity help a generater work?
Generators create electricity, where there is none in the first place. Power is provided to rotate coils inside each other. The more power that is required, needs more force to turn the coils, which become heavy with increased load. One set of coils is made into a magnet, by passing a controlled amount of electricity through them, to stabilise the amount of voltage and current required. Ironically, this requires electricity to produce electricity and is known as an 'excitation' current. This is sometimes provided by a separate unit on the generator, which has permanent magnets inside it and can produce a small excitation voltage to get things going. Excitation current is then provided by circuits running off the main output.
What best describes the events of excitation in excitation-contraction coupling?
cross bridge formation "Excitation-contraction coupling" connects muscle fiber excitation to the muscle fiber contraction (cross bridge formation). During contraction, myosin heads form cross bridges many times-with each cross bridge generating a small amount of tension in the muscle fiber.
How much heat is generated in a nuclear fusion?
In nuclear fusion, a small amount of heat is generated due to the high temperatures required to fuse atomic nuclei together. This heat can be harnessed to produce electricity through various methods, such as heating water to create steam to drive a turbine. However, the amount of energy produced by fusion reactions is significantly greater than the heat generated.
Why does the no-load characteristic differ for increasing and decreasing excitation current?
The no-load characteristic of a generator differs for increasing and decreasing excitation current due to magnetic hysteresis, residual magnetism, and core saturation effects. When the excitation current increases, the magnetic domains in the iron core gradually align with the applied magnetic field, resulting in a higher generated electromotive force (EMF). However, as the excitation current decreases, these magnetic domains do not immediately return to their original unaligned state. This lag in realignment causes the generated voltage to remain higher during the decreasing phase of excitation than during the increasing phase at the same level of excitation current. This phenomenon is known as magnetic hysteresis. Even when the excitation current is zero, the magnetic core retains some level of magnetisation, known as residual magnetism. This residual magnetic field means that when the excitation current starts increasing again, it takes additional current to overcome this residual alignment before the generated voltage rises significantly. As a result, the voltage is initially lower when increasing the excitation current from zero. Conversely, during the decreasing phase, the residual magnetism keeps the voltage higher than it would be if the core were fully demagnetised, further contributing to the difference between the increasing and decreasing curves. As the excitation current increases, the magnetic core of the generator approaches saturation. Near saturation, any further increase in excitation current results in only a small increase in generated voltage because the core's magnetic domains are almost fully aligned. When the excitation current decreases from this saturated state, the magnetic domains gradually return to a less aligned state. This gradual realignment causes the generated voltage to decrease differently than it increased, contributing to the asymmetry between the increasing and decreasing excitation phases.
Do electricity meters consume electricity?
Yes, electricity meters consume a small amount of electricity to power their internal components such as digital displays and communication modules. This small amount of electricity consumption is accounted for in your overall energy usage.
Why do cell phone chargers use electrity when they are not pluged into phone?
There is a certain small excitation current that is generated by the step down transformer in the charger. It is that current that keeps the charger warm to the touch even when there is no phone plugged into it.
How can you get electricity from water?
One of two ways: 1. Drop large amounts of water through turbines (generators) and electricity is created in the turbine windings. 2. Press water at high pressure through micro-tubes in a disk of glass. A small amount of electricity is generated. But, it takes electricity to pump the water up to high pressure, so no new energy can be created.
How electricity gathered?
by wires <<>> Electricity is not a collectible commodity. It is generated and distributed as the demand requires. Small amounts of DC electricity can be stored in a capacitor but is not viable as an AC source. Electricity is distributed by wire conductors.
How much electricity can an lemon produce?
On average, a lemon can produce around 0.5 volts of electricity. This is possible because the citric acid in the lemon acts as an electrolyte which allows a chemical reaction to occur with two different metals acting as electrodes. However, the amount of electricity generated is very small and not practical for powering devices beyond basic experiments.
Can a bicycle paddle be used as a turbine to generate small amount of electricity?
Yes, it can. But you will need a great amount of force to rotate it.
Is it possible to generate electricity from rainwater in a downspout with small turbine's in a series and store the energy?
Yes, it is possible to generate electricity from rainwater using turbines in a downspout. The kinetic energy from the flowing water can be converted into electrical energy through the turbines. This generated electricity can be stored in batteries or a power grid for later use.
