The way the cable is laid always depends on such factors: the type of electrical wiring (hidden / open), the category of the room (domestic, industrial, and so on) and the material from which the building is built, that is, its combustibility.

In residential premises, most often, hidden wiring is preferred. Most people who are far from electrical work imagine it this way: a groove (in a professional language - a shtroba) on a wall or ceiling in which cables are wired, reaching for outlets, boxes and switches. Actually, this option of hidden wiring is the most common.

But what to do if the wall bearing and gating can weaken its structure? Or another option: a wooden house. In addition, it’s not very convenient to shatter a tree, because it’s also not clear how to cover it later. And, even by hiding the cable in a wooden wall, we grossly violate the fire safety rules ...

Electrical current and hazardous voltage cannot be heard (except for humming high-voltage lines and electrical installations). Live parts under voltage do not differ in appearance.

It is impossible to recognize them both by smell and by elevated temperature in normal operating modes, they do not differ. But we turn on the vacuum cleaner in a silent and quiet outlet, click the switch - and the energy seems to be taken out of nowhere, by itself, materializing in the form of noise and compression inside a household appliance.

So, we will consider one, the most valuable law of electrical engineering, which is useful to know. And try to do it in the most popular form possible.

The most important law of electrical engineering is, of course, Ohm's law. Even people unrelated to electrical engineering know about its existence. But meanwhile, the question “Do you know Ohm’s law?” in technical universities is a trap ...

This is not uncommon. With great difficulty, we hang a carpet on the wall, but we are not happy with the result for long: for some reason, the lamp in the room stops burning. Or we drill a hole in the wall to hang a shelf, but sparks fly out from under the drill, a crack sounds, and the apartment plunges into an ominous darkness and silence.

The cause of unhappiness is usually simple to disgrace - we were out of luck, and we damaged the cable hidden electrical wiring. In the case of the carpet, most likely, a phase or zero core was interrupted. And when they prepared the holes for the shelf, they damaged the insulation of both cores and made a short circuit (the drill can, of course, be thrown away right away).

To resolve the situation, the damage to the line must, of course, be found. In the case of the shelf, this will not be any difficulty - where they fought at the time of the short circuit, there is a damaged area ...

Currently, wind energy is undergoing a rebirth. The thing is that before the energy produced by windmills was more expensive than it was sold to the population and enterprises from the Unified Energy System of the Soviet Union. In the West and in the rest of the world there was something similar. And all because the wind systems were ineffective.

Now much has changed: durable and cheap plastics and other materials have appeared that are more suitable for large windmills; there are new types of permanent magnet generators, and other developments that allow more efficient conversion of wind into electricity; new electronic and electrical systems for controlling windmill systems have appeared without the constant participation of humans; fuel has become more expensive: oil, gas, coal, fuel oil.And it became expensive to use: they need to be cleaned after combustion, disposed of so that it does not enter the atmosphere, land and water bodies ...

The choice of sockets for stoves and washing machines. The selection is made according to some basic operating parameters. Here they are:

1. The number of phases required to power the electrical receiver, that is, its "phase". In any case, a three-phase connection requires a socket with five connectors: L1, L2, L3, N and PE. A single-phase power supply is enough for a socket with three connectors: L, N and PE. Three-phase in our case can only be a stove, and even then only if it is possible to connect to a three-phase network.

2. The rated current load on the outlet. The passport of any device usually indicates electrical power, and data on the current drawn from the network may not be available. But electric power is never indicated on the body of electrical outlets - there is only information about the maximum permissible current ...

One of the first inverter circuits for powering a three-phase motor was published in Radio magazine No. 11 of 1999. Scheme developer M. Mukhin at that time was a student of grade 10 and was engaged in a radio circle.

The converter was intended to power the miniature three-phase motor DID-5TA, which was used in the machine for drilling printed circuit boards. It should be noted that the operating frequency of this engine is 400Hz, and the supply voltage is 27V. In addition, the midpoint of the motor (when connecting the windings with a “star”) was brought out, which made it possible to extremely simplify the circuit: it took only three output signals, and each phase required only one output key. As can be seen from the diagram, the converter consists of three parts: a three-phase pulse generator-shaper: a three-phase pulse generator-shaper on microcircuits ...

In industrial environments, three-phase asynchronous motors are most commonly used. The simplicity of their design, reliability and low cost - these are the decisive factors that allow you to use them in many machines, units and mechanisms. In most cases, engines operate on an on-off basis.

In almost all metal-cutting machines, the spindle speed is controlled by a mechanical gearbox. Moreover, it is not necessary to control the engine speed to change or maintain any technological parameter in the norm. As such a parameter, for example, one can consider the pressure at the outlet of a conventional water pump used in plumbing systems. Each of us is familiar with this parameter - just open the washbasin tap in the morning. About twenty years ago, the task of regulating pressure ...

They will not need to be brought in frosts at night in the heat. They will be much cheaper than ordinary ones, because plastic is cheaper than non-ferrous metals. Their service life will exceed the life of the machine itself. They will be charged from electric motors, from energy recovery during braking, from stationary energy sources.

These are inertioids, or flywheels. They store energy and then give them to consumers as needed. With a large flywheel and internal combustion engine is not needed. Energy can also be stored at refueling stations, powering one or more flywheels with powerful electric motors. They are in a sealed airless space, and are suspended on powerful magnets. They are called super-flywheels, since they store energy thousands of times more than ordinary flywheels. They were invented 50 years ago by the Russian scientist N. Gulia, but they were not used en masse.Only a few artisanal developments ...