The simplest and most widely used method that ensures the operation of a three-phase electric motor from a household network is to connect one of its windings through a phase-shifting capacitor. The article discusses in detail the issues of calculating engine power and capacitance of a capacitor for various switching schemes.

To calculate the motor power and capacitance of the capacitor, you need the following data: N - power in kilowatts, I - current in amperes, efficiency. This data is on the tag of each engine.

Usually, two currents are given on the tag - for the star and for the triangle. You need to take a current for the star. We will extract other data from them: Na = 1000 * N / (3 * Efficiency), W is the active power of the winding, Z = U / I, ohm is the impedance of the winding, U = 220 V is the voltage across the windings, R = Na / I2 , ohm is the active resistance of the winding. This resistance cannot be measured by a tester and you will not see it when disassembling the engine. In explicit form, it is not. It appears only when working ...

When mounting electrical cabinets, sometimes it is necessary to mount rather massive components on the mounting panel that cannot be fastened tightly, because they need to be removed from time to time for various reasons - for replacement, for maintenance, etc., for example, electricity meters (meters ), frequency drives, etc. Usually they are fixed with screws.

For this, it is necessary to provide threaded holes in the mounting panel so that when they are removed, the entire panel in the mounted cabinet must not be removed in order to get the fixing nuts from the back of the panel.

With their small diameters, a panel made of a thin sheet is enough to bulge and cut the M3, M4 thread into them, but for greater bearing capacity with the M5, M6 threads this way you can’t do, because you cannot make such a thread in a thin sheet of a panel. It is necessary to put threaded bushings in these places. At the next trip, the store in the fastener department, I came across threaded rivets ...

One of my friends turned to me with this request: they say, I want the fireplace to turn on in the garage on a call from a cell phone. He has a workshop there, and it’s cold in the mornings, so he wants to turn on the fireplace two or three hours before arrival. Everything is very simple: he turns on the fireplace by phone, and two hours later, if he does not come, the fireplace will simply turn itself off.

Talk that this is easier to do if you buy a programmable relay did not convince him. Apparently, he might not have appeared there on some days, but this was not amenable to any accounting when programming the relay. And he would spin the counter there while the fireplace was warming an empty room.

Nowadays, there are already many industrial devices that are controlled by the GSM (Global System for Mobile Communication) standard — a digital standard for mobile communications or a now familiar mobile phone. This is a burglar alarm, various control cabinets ...

Single-phase motors are electric machines of low power. In the magnetic circuit of single-phase motors there is a two-phase winding, consisting of the main and starting windings.

Two windings are needed in order to cause the rotation of the rotor of a single-phase motor. The most common motors of this type can be divided into two groups: single-phase motors with a starting winding and motors with a working capacitor.

For engines of the first type, the starting winding is switched on through the capacitor only at the time of starting and after the engine has developed a normal rotation speed, it is disconnected from the network. The engine continues to work with one working winding.The value of the capacitor is usually indicated on the nameplate of the motor and depends on its design. Single-phase AC induction motors with a working capacitor have an auxiliary winding ...

Practical ways of saving electricity in everyday life that do not require large investments and obtained experimentally!

Due to the constant increase in electricity tariffs, it becomes more and more relevant to limit the cost of its payment. There are many ways to do this. The most fashionable ways to save energy in everyday life are those related to new technologies, quite a lot has been written about them.

However, there are opportunities that do not require large expenditures and special knowledge; they will help you if you follow the elementary rules of energy consumption culture. Consider these features in detail. Savings in lighting public spaces Usually, when considering this issue, they suggest installing motion sensors and energy-saving lamps in stairwells and basements. In this case, the price of the question ...

There are several ways to power a light bulb with a small voltage from an electric circuit with a high voltage. The article discusses the options for connecting the bulb to a different voltage by selecting additional resistance from a high-resistance wire and using diodes in series in the “forward direction”.

Suppose we need a light bulb rated for 6 volts and a current of 0.5 amperes turned on from a 12 volt battery. The simplest of the switching circuits consists of a light bulb connected in series, an additional resistance Rdop and a voltage source Ua, a battery. It is necessary to select additional resistance in such a way that a voltage of 6 volts “drops” on a bulb with a current in the circuit I = 0.5 amperes. Resistance is made from any high-resistance wire ...

The figure shows a typical task. VVG cable 2 × 1.5mm2, consisting of two single-core conductors coated with insulation and placed in a black protective sheath. How to remove the sheath and insulation from the cable so that it is fast, safe, quality and reliable? Moreover, by quality I understand here the stability of the result.

Of course, when it is possible to remove the insulation from the cable on the table, and not in a tight socket, and you need to make a couple of connections, everything can be done slowly, measured, checking every step. And if you need to make an apartment in front of plaster in a couple of days?

I tried three options for removing the insulation from the cable and stopped, as usual, on the third: stripping with a clerical knife, stripping with a special knife of the installer, stripping with a special device ...

In every modern house - apartment, of course, there is an extensive electric network. Each room has one or two outlets. But, as on purpose, they are usually located in the wrong place. Or the number of electrical appliances that must be turned on exceeds the number of outlets. Or you must turn on a portable appliance, such as an electric heater.

These electrical appliances sometimes consume significant electrical power. Then portable extension sockets come to our aid. The cable for such a portable outlet is necessarily selected in double rubber insulation (the wires themselves are insulated and additionally placed in an external insulating sheath). Best when the wires in the cable are stranded, flexible. The diameter or cross-section of the wires must correspond to the permissible electrical load. What should be the cross-section of the cable wires? ...