How to connect a three-phase engine from a pylon. Starting an asynchronous dvigun to switch from the star to the trikutnik

Start short-circuited electric motor s chime s stars in tricoutnik zastosovuyut descent of the starting strum. The starting strum at start-up can outweigh the working strum of the electric motor by 5-7 times. In engines with great pressure, the starting strum is large, which can cause the burnout of other guards, turning on the automatic switch and bring it to a significant decrease in voltage. Changing the voltage reduces the fuse of the lamps, changes the torque of the electric motors, can also turn on the contactors and magnetic starters. For that, it’s good for someone to change the launch strum. It can be reached by means of dekilkom, but the stink as a result is reduced to a decrease in voltage in the stator of the electric motor during the start-up period. For the first stator lance, for the start-up period, introduce a rheostat, a choke, an autotransformer, or switch the winding from the star to a tricutnik.

Curation scheme.

Connecting the operational voltage through the contact of the relay to the hour K1 and contact K2 in the coil of the contactor K3.
Switching on contactor K3, opening contact K3 in the contactor coil coil K2 (blocking the warning switch), contact K3 is closing, contactor coil coil contactor K1 mixed with the pneumatic clock relay.
Switching on the contactor K1, closing the contact K1 of the coil of the contactor K1 coil (self-sustaining), one hour the pneumatic time relay is switched on, as soon as it opens its contact K1 of the coil of the contactor K3 coil, as well as closing its contact K1 of the coil of the contactor K2.
Switching off contactor K3, contact K3 closes in the coil of contactor K2.
Switching on contactor K2, opening contact K2 at the coil of contactor K3 (blocking the intercom).

Eating scheme.

On the cob of windings U1, V1 and W1 through power contacts magnetic launcher K1 is served three phase voltage. When the magnetic starter K3 is used for additional contacts K3, there is a flicker, connecting the ends of the windings U2, V2 and W2 between the windings of the motor with a spark.
After a certain hour, the time relay starts, summing up with the starter K1, turning on the starter K3 and switching on K2 at the same time, the power contacts K2 are switched on and the voltage is supplied to the ends of the windings of the electric motor U2, V2 and W2. In this rank, the electric motor is turned on for the trikutnik circuit.

Advance.

1. Switching from star to trikutnik is permissible only for engines with easy start-up mode, splintering when it is turned into star, the starting moment is approximately two times smaller for the moment, which is like a buv bi with a direct start. So, this way of lowering the starting jet does not have to be attached, and it is necessary to reduce the starting jet and reach a great starting moment at once, take an electric motor with a phase rotor, and introduce a starting rheostat into the rotor lung.

2. Only electric motors can be switched from zirka into a tricoutnik, as they are used for work when plugged into a tricoutnik, so that windings can be washed, rozrakhovanі on line voltage merezhі.

Starting asynchronous motors using the least expansion method - I'm switching from star to trikutnik.

The way to switch from a star to a tricoutnik is to be found in motors, like insurance for work when the windings are wound by a tricoutnik. This method works in three stages. The engine is started on the cob when the windings are turned on with a star, at which stage the engine is opened. Let's switch to a working scheme for setting up a tricot, moreover, when switching, it is necessary to protect a couple of nuances. In the first place, it is necessary to correctly open the hour of the twirl, so that if the contacts are closed in advance, then the electric arc will not go out, and you can also winknut short chirp. If it’s too early, it’s possible to bring the engine to waste, and as a result, to increase the throw of the struma. With a zagal, it is necessary to clearly set aside the hour of perekykannya. At the third stage, if the stator winding is already connected by a tricotor, the engine will switch to the robotic mode.

The sense of this is that, when the windings of the stator are zirkoy, the voltage phase in them is reduced by 1.73 times. At the same time, the number of times changes and phase strum what flows in the stator windings. When the stator windings are connected with a tricotnik, the phase voltage is higher than the linear one, and the phase stream is 1.73 times less than the linear one. Come out, z'ednuyuchi windings with a star, mi changing the linear stream of the morning.

So as not to get lost in the numbers, let's look at the butt.

Permissible working scheme the windings of the asynchronous motor are tricooled, and the line voltage is 380 V. The opir of the stator winding is Z = 20 Ohm. By connecting the windings at the time of starting with a star, we change the voltage and the jet at the phases.

The strum at the phases is closer to the linear strum and older

After the acceleration of the dvigun, we switch from the star to the tricout and take other values ​​of the voltage and strum.

How to bachite a linear strum with a tricutnik more than 3 times line strum with the star.

What way to launch asynchronous motor zastosovuetsya in quiet vibrations, if there is little pressure, or if the engine is idling. This is due to the fact that when the phase voltage is changed by a factor of 1.73, according to the formula for the starting torque, as it is given lower, the moment changes by a factor of three, and this is not enough to improve the start-up from the stress on the shaft.

De m - number of phases, U - phase voltage of the stator winding, f - frequency of the live stream, r1, r2, x1, x2-parameters of the substitution circuit asynchronous motor- Number of pairs of poles.

The main ways of connecting three-phase electric motors are zirka chi trikutnik. Tse okremі vpadki, if three-phase desire connect via automatic wimicach. The most common way to win is the universal connection of the dviguna - “star-tricutnik”. With this, a three-phase electric motor can be connected to the main electrical wiring.

Ways of connection: zirka and trikutnik

The connection of the dvigun in two ways, that is, with a star and a tricout, is connected to simple jumpers, installed on the wells of the terminals between the windings of the windings.

The contacts of the motor windings are connected to the contacts of the terminal box. Tsya is an electrical connection, at its own core, with the windings of the engine and the phases of life. At the terminal box, special jumpers are installed, which allow switching from the “trikutnik” position to the “star” position. The supply of life is stored in a tricutnik, yakі utvorenі by the windings of an electric motor. When connected with a “star”, the jumper is inserted in such a position that all three windings are connected at one point.

At the "trikutnik", navpaki, the skin winding is tied with another double winding. Oskіlki navantazhennya in all windings є equal, in the case of demand for neutral dart. IN modern minds The connection circuits are often wicked in order to switch from the “star” mode to the tricouter. With this, the starting mode of the electric motor is significantly assisted. However, the connection of the contactor itself does not change the general scheme, it is just that between the electric motor and the automatic machine there is an additional power attachment, which is included in the contactor's sprat.

Switching from different positions

If the electric motor moves from the “tricutnik” position to the “star” position, there will be a decrease in the tightness of the third. As if mimicking at the right turn, the stiffness of the dvigun, on the other hand, increases sharply. If you keep in mind that the electric motor is not intended for work in these minds, then you can just burn out.

The connection of the dvigun - the "spark-tricutnik" is zastosovuetsya in order to change the starting strum, which is more important for the working strum of the dvigun. In electric motors of great pressure, the value of the starting struma of the floor is great, which can cause serious consequences and lead to a drop in voltage. Under the hour of the starting process, the frequency of the wrapping of the electric motor increases and changes the stream. The next winding is switched to the tricout mode.