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The conversion of a direct current into an alternating current in a dynamic capacitor is carried out due to the periodically changing capacity of the capacitor when one of the plates oscillates.
The conversion of a DC to an AC is called inverting, and the device that performs this function is called an inverter.
1-pole configuration with earth return. 1-pole configuration with return wire. This line consists of two 12-frequency converters on each side and two conductors with the same voltage, but with opposite polarity. In this case, during normal operation, only a small balancing current flows through the grounding or special conductor. In comparison with the single-pole configuration, it has double throughput and higher reliability of operation.
In case of a fault on one of the inverters, the second conductor can be used as a return path for the current and operate on a 50% power line. In the event of a fault on one of the lines, the other can again operate with 50% power and use the ground or the third conductor as the return path, if any.
Conversion of DC to AC and modulation of AC signals. To amplify the DC voltage, amplifiers with direct galvanic coupling between the cascades are usually used. A significant drawback of all direct current amplifiers is zero drift. The presence of zero drift and the difficulties of directly amplifying small constant voltages caused a series of amplifier circuits with the conversion of DC voltage to AC and the amplification of the latter by an AC amplifier. The converters are mechanical, microphone, electronic and other devices.
The "zero length" manual
2-pole matrix with ground return. 2-pole configuration with return wire. The name suggests that the rectifier and inverter are located close to each other - usually in the same building. The function of this arrangement is primarily connected with the connection of two non-synchronous alternating systems and can also serve as a tool for determining the direction of the energy flow, which in conventional ac systems is usually impossible.
Unlike remote lines, these stations have a relatively low voltage. Losses due to high currents are not as high as the length of the line. For lower voltages, there is no need for a large number of semiconductor devices based on the series, as well as lower insulation requirements, which leads to space savings.
Conversion of direct current to alternating current is carried out by periodically interrupting the load power circuit. If the level of the output voltage of the converter is different from the level of the input DC voltage, the load is switched on via the transformer.
Typical applications for DC traffic include long cable lines, especially underwater cables with a long cable can not be used because of high capacity. This is mainly the supply of electricity from remote sources, often located hundreds of thousands of kilometers from the points of consumption. Similarly, it is the connection of loads very far from transmission networks.
With increasing pressure on the use of renewable resources, large farms or parks, both solar and wind farms, are being built. Wind power stations are often located on the sea, where weather conditions are better. Dedicated transmission is proposed as a suitable and, in some cases, the only option for efficient and reliable transmission of generated electricity to points of consumption.
Convert DC to AC and reverse conversion.
Conversion of direct current to alternating (inverting) can be carried out by means of electric gates, the conductivity of which can be controlled. Thyristors are used for this purpose. As it was shown, the rectifier with phase control and a network-driven inverter (inverter, whose frequency of frequency corresponds to the network frequency and P0 Rin) work in the same way and any of these modes can be implemented in the same circuit. When operating as a rectifier, the device transfers energy to a DC load. When it works as an inverter, a constant voltage source is needed to create a current in the device and transmit power to the AC side, the inverter mode occurs at a 90 h - 180 e. A network-driven (non-autonomous) inverter is used for rheostat tests of diesel locomotives with energy recovery. Such attitudes about every year are becoming more widespread.
What is the reason for this attitude? They were personal and real technical reasons. For these people there was a special habit, and understanding and calculating DC circuits was easier. It is easier to imagine that sources have a positive and final signal that the current flows without interrupting the conductor and is easily recorded in accordance with Ohm's law. The use of Ohm's law does not require a high degree of mathematical knowledge, with four basic practices stacked. Confusion arises in the first stage when determining the AC current.
Conversion of a direct current into an alternating current is made by a capacitor, the capacity of which periodically varies (for example,
The motion of charged particles (electrons and ions), which is directed or ordered, is called an electric current. The electric current can be alternating current and constant.
The current voltage constantly changes its value between its maximum negative and positive values. However, the use of the current flow retained real technical reasons. First, there was a failure for the streaming. The biggest problem was the lack of an easily executable and well-controlled electric motor. Because of the lack of creeping current, it was thought that it could not be saved. DC power can be stored in batteries. Batteries also increased their performance in the event of a dynamo failure.
An electric current with constant properties and direction is called a constant current. A constant current is necessary for the operation of all electrical appliances. All electrical equipment, powered by a battery, also consumes direct current. The battery and battery are sources of direct current, with the help of a converter it can be turned into an alternating current. DC and AC, what are their differences?
The issue of this issue was not the storage of electricity, but in conjunction with power plants. The ultraviolet current can be transported over long distances, so that, if necessary, power stations can help. The network connects hundreds of plants with continental ranges. His role was not only in technical, but also in economic competition. The old, established companies in the 1980s had large-scale electrification.
It is clear that they used their system. "New" companies struggled with the problem of market share. In Budapest, in the 50th century, the stream of direct current was represented by the great "joy" of the inhabitants, who could not use ordinary radio and television equipment and prayers. With the help of the Gants factory, they were forced to fight for the flow of streams. This was the first in Germany system! The spread of the creep flow is better than the absence of a good motor. Although Gantz produced a synchronous and commutator motor, they were more complex and expensive than DC motors, and performance was also unsatisfactory.
When the value changes according to the sinusoidal law, then such an electric current is called variable. It is characterized by frequency and voltage, it is single-phase and three-phase.
Everyone knows that the voltage supplied by the outlet is 220 volts, but it is not constant, but the maximum voltage can reach over 300 volts.
Electrical engineering was waiting for a new, simple, reliable and inexpensive electric motor. The inventors of the phantom system were - indifferently - Galileo Ferraris and Nikola Tesla. Three-stage power transmission and an asynchronous motor suitable for industry were exhibited at the Frankfurt International Electrotechnical Exhibition in the Special Year of the engine. The engine radiated a simple design and reliability. In a so-called asynchronous motor with an anchor, the cutter is not a switch, it is not necessary, the anchor is not in the correct sense of the wound, but the metal key.
Accordingly, the constant has the direction of motion of electrons that does not change during time, and the magnitude of the voltage, and the voltage of the alternating current is constantly changing. The difference between AC and DC is in the magnitude of the voltage.
An important characteristic of an electric current is the frequency
It is measured by Hertzs, representing the ratio of the number of repetitions to the time interval for which they are committed. Russia applies the frequency of 50 Hz.
Since then it is the cheapest and reliable electric motor. Electric generators generate a direct current. In DC circuits, the current value and current are constantly changing, and the description of such circuits is much more complicated than the circuits in which the current flows through the direct current. Therefore, in this article we give only basic information and the most important relationships.
The impedance and phase shift of the current and voltage in a particular circuit can be very complicated - it depends on the characteristics of the connected elements and the frequency of the current. Cold current power Output power - in addition to direct current - depends not only on voltages and currents, but also on the phase shift between them. For the power of the current of the vine it is applied: A great one is called an error. That's why.
In practice, the frequency of 50 Hz means that the flow of electrons oscillates, and its direction changes 50 times per second.
In all electrical outlets, an alternating current flows. The use of AC, rather than DC, is associated with the possibility of transmitting electricity over long distances without significant losses. This, in fact, distinguishes the direct current and also the variable one. The electrical substation is supplied with a voltage of 220,000 volts or more, then in a transformer substation located close to residential buildings, it is converted from 10,000 to 380 volts and sent to the consumer.
The design of electric motors is important for the maximum possible phase shift. While in a single-phase current generator the induction voltage is induced by only one, the three-phase current generator has three blades whose axes ostensibly oscillate by 120 °. Therefore, three volumes are always shifted by one third of the period. Mathematically, you can prove that at each moment all three volumes are zero. Individual conversions can have six wires from a three-phase generator, but in practice the connection is connected in one of two ways.
Electric motors working on alternating current are much simpler in design and more durable.
Variable in a permanent transform with the help of rectifiers. First connect the diode bridge to make it unidirectional. Then, it is necessary to connect a capacitor or a smoothing filter to correct the dip between the peaks of the sinusoid.
The electric current is diverted by three conductors, between which two is a 400 V power supply connected to the star-the triggers of all three elements are connected to one grounded node, the conductor connected to the node is zero conductivity.
- Enabling the triangle: - the end of the button is always linked to the beginning of the next line.
- The so-called phase conductors are connected to the end of the plug.
The direct current and also the variable are transformed in an instant, but with the reverse change of things are much worse. That is, the variable in the constant is more difficult to transform. For this, it is required to use an inverter, a rather complex and expensive device. Typically, such a conversion is rarely required, for example, if you want to include electrical appliances in the vehicle's on-board network.
Such solutions also contribute to the need for high power, noise immunity and transients. The following article describes industrial applications that can be implemented using a distributed architecture.
Power converters for railway applications
This signal is then distributed over the wires through the vast areas of crossovers, switches and Signals that make up the transport infrastructure and are considered the main power source for communications, monitoring and control systems. Its output is galvanically isolated from the input, which reduces the interference caused by the extended 12 V installation, which affects the reliability of the entire system.