The stress between the phases of a three-phase line is the formula. Vіdgoryannya zero. Single-phase slowdown in a three-phase line

You know you What is a gedanken experiment?
This is not a real practice, a potoybіchny dosvid, I will reveal what is really not known. Dumkov's experiments are similar to waking dreams. The stench is making monsters. On vіdmіnu od fіzichnogo eksperimentu, yaky Je dosvіdchenoyu perevіrkoyu gіpotez, "uyavny eksperiment" fokusichno pіdmіnyaє experiental perevіrku Bazhanov not perevіrenimi on praktitsі visnovkami, manіpulyuyuchi logіkopodіbnimi pobudovami scho really porushuyut itself logіku Shlyakhov vikoristannya nedovedenih posilok yak dovedenі. Otzhe, the main task of the applicants in "experimental experiments" is the deceit of the hearer and the reader with a way to replace the right physical experiment with yoga "lyalkoy" - fictitious mirkuvannyami pіd word word without the actual physical reverb.
The filling of physics with obvious, "explainable experiments" has led to the vindication of an absurd surrealistic, confused and confused picture of the world. The right reporter can add such "wrappers" in the form of right values.

Relativities and positivities confirm that the "dumkov experiment" is a fundamental tool for re-verifying theories (they also blame our minds) for non-superity. Whose stench is fooling people, shards, whether it be a re-verification, can be more independent than an independent type of re-verification object, dzherel. The applicant himself of the hypothesis cannot be re-verified in his statement, but the reason for his own statement is the existence of super-judgments visible to the applicant in the application.

Tse mi bachimo on the butt of SRT and OTO, which have turned into their own kind of religion, cherished by science a huge thought. Except for the number of facts that supersede them, you can’t fix Einstein’s formula: “If a fact doesn’t support a theory, change a fact” (In the other version, “A fact doesn’t support a theory? - Tim girsche for a fact”).

As much as possible, what a "experimental experiment" can claim - it is only for the internal non-superability of the hypothesis within the framework of the applicant's own, often not correct, logic. Vidpovidnist praktitsі tse do not change. This re-verification can only be done in a practical physical experiment.

An experiment on those experiments that win is not a rethinking of a thought, but a re-verification of a thought. A thought that is not superlative in one's own mind cannot be distorted by itself. Tse finished by Kurt Gödel.

The phrase about zero chuv, mabut, skin of us. Why is the taєmnichiy zero may tend to gradually burn out? In order to bring clarity to the mainstream, it is necessary to guess something in the middle school physics course.

For single-phase lanceug"zero" is just a name for a conductor who does not know about the high potential of any earth. Another conductor in a single-phase lance is called a "phase" and may be visible to the earth high potential variable voltage(Our edge bowl has a total of 220 V). The current trends until the emergence of a single-phase zero do not show.

Bіda at tsomu, scho tse electrical communications (i.e., lines of power transmission) are three-phase. Let's look at the "zirka" scheme, in which case the "zero wire" is understood.

Changes in the streams of the skin phase in three equal vanishings are put in phase exactly by one third and ideally compensate for one another, so the vanishing in such a scheme is called a three-phase zoseredzhennym vanishing. With such an ambition, the vector sum of the streams at the middle point is equal to zero. Zero wire, Connections to the middle point, practically not needed, because the strum does not flow through it. An insignificant strum appears only once, if the pressure on the skin phase in the same way is not the same and does not fully compensate for one another. In fact, a lot of views of three-phase choti-core cables can be found in the zero core of a double-width smaller overcut. There is no sense of staining a scarce copper on a conductor, as a stream is a little leaky. The current tendencies to extinction do not show a three-phase zero in case of a three-phase segregated vanishing.

Umov: R1 = R2 = R3
I = i 1 + i 2 + i 3 = 0

Miracles begin only if single-phase advancement is connected to three-phase lances. At first glance, that very vapadok, but there is one small vіdminnіst. Skin single-phase tension is a type of attachment, so single-phase tension is not the same. It is unreasonable to think that different single-phase dampers will be slower than the same stream. Single phase drive in triphasic lancers zavzhdi magayutsya as close as possible to . This means that when single-phase relaxations are connected to a three-phase line, they are so divided for tension in different phases, so that approximately the same tension fell on the skin phase. Ale povnoi zealousness is by no means within reach and understood why. Spozhivachі vpadkovo turn on and mimic their elektroobladnannya, by the same time constantly changing the attraction to their phase.

As a result of new compensation phase streams in the middle point, it is practically not observed, but the strum at the zero droit does not sound at its maximum value, which is more favorable to the largest strum in one of the phases. So the situation is unacceptable, but it’s overdone. All wiring is insured for her, that zero obviously it doesn’t happen, but if it does, it’s very rare.

Umov: R1 ≠ R2 ≠ R3
I \u003d i 1 + i 2 + i 3 ≠ 0
I max ≤ i n max

This situation developed until the 90s of the twentieth century. What changed at that hour? Wandered widely impulses dzherel eating. Such a dzherelo zhivlennya is practical in all modern on-the-go equipment (television viewers, computers, radio receivers, etc.). The entire strum of such a dzherel flows with a stretch of one third in a single period, i.e. the character of the strum’s stunting is even more striking in the light of the nature of the strum’s stimming with classic vanities. As a result in three-phase mesh blame additional impulses of the stream, which are not compensated in the middle point. Do not forget to add to the uncompensated strumi, caused by the presence of single-phase windings in a three-phase line. In such a situation, a strum often flows along the zero dart, or close or outweighs the largest strum of one phase. Tse і є um, pryatlivі for vіdgorannya zero.
Conductors in three-phase cables may have a slight overcut, which can be opened up to the maximum tension tension, also, null explorer may be the same perepirz, as if it were one of the phase conductors, and the strum through the new one today may flow more, lower through any phase conductor. To come out, that the zero explorer is working in the minds of adventurousness, and the mindfulness of his mind is growing.

Umov: R1 ≠ R2 ≠ R3
I \u003d i 1 + i 2 + i 3 ≠ 0
I max > i n max

So in the 90s of the last century, we unremembered for ourselves entered the era of "zero". On a daily basis, the situation is getting worse. It is necessary to insure the high possibility of “when the fire is zero” and if you need home electrical wiring.

Laboratory robot 8 THREE-PHASE LANTSYUGI. Z'DNANNIA NAVANTAGE ZIRKOM Meta robots: Vivchiti lanciug triphasic struma when z'ednanny priymacha with a star in symmetrical that asymmetric modes. Designate the role of the neutral (zero) dart. BASIC CONCEPTS electric lancers, They have sinusoidal EPCs of the same frequency, phase failures for 1/3 of the period and the creation of a sparkling electrical energy. The triphasic system was found in all details by the talented Russian engineer M.O. Dolivo-Dobrovolsky in 1891. A three-phase generator serves as the source of energy in a three-phase system. At the grooves of the first stator there are three electrically isolated ones, one type of one winding (phase winding or just phase) of the generator. Since the rotor is a two-pole generator, then the os-phase windings of the generator are rotated in space, visually one per coil 2p /3. When wrapping the rotor, the phase windings of the stator are induced sinusoidal phase EPC. Due to the symmetry of the generator design, the maximum Em and E EPC values ​​for all phases are the same. Z'ednannya phases (windings) of the generator can be zdіysnyuvatisya for the scheme "zirka" or "trikutnik". Fazi three-phase generator it is accepted to designate the first letters of the Latin alphabet: A, B, C. in the blackness of EPC maxima: first of phase A, then after 1/3T of phase і through 2/3T of phase C. Such a sequence of drawing is called a straight line. Mittevi EPC values three-phase windings equal generator: eA=Emsinw t eB=Emsin(w t-2/3p) eC=Emsin(w t-4/3p) (1) . Rice. 8.1 3 As can be seen from Fig. 8.1, the sum of the mitigated values ​​of the EPC at any time is equal to zero, then, the geometrical sum of the variable values ​​of the phase EPCs of the generator is also equal to zero: eA + eB + eC = 0 (2) EA + EB + EC = 0 See Fig. 8.1, the apparent complex value of the EPC of a three-phase generator through the same for all three phases chinne meaning E, then EA=E∙ej0 EB=E e-j2/3p (3) EC=E e2/3p . At the given hour three-phase systemє the main for the transfer and distribution of energy. The phases of the windings of a three-phase generator can be connected from three receivers using the “star” circuit. "Zirkoy" is called such a connection, at the end of the phases of the connection to one central point N, it is called neutral or zero, and before the cobs of phases A, B, C, the introduction of linear darts. At the "star" the phases of vanishing start with the zero point n and the cobs of phases a, b, c (Fig. 8.2).

Fig.8.2 See what is coming points N-n called neutral or null. See what's coming points A-a, V-in and S-s, they are called linear. Having accepted the support of all dross equal to zero, it is possible to designate the three phases of the acceptance of the generator: IA=EA/ZA; IB=EB/ZB; IC=EC/ZC. (4) Strumi IA, IB, IC, which flow along the linear darts, are called 4 linear (IL). Strumi, which flow in the phases of the generator and in the phases of the input are called phase struma(IF). For z'ednannya "zirkoy" linear streams equal phases, then IЛ=Iф (5) The strum at the neutral dart according to the first Kirchhoff law is more advanced: IN=IA+IB+IC (6) Acceptances with the same support of all three phases Za=Zb=Zc are called symmetrical. With a symmetrical approach IA=IB=IC i strum at the neutral dart IN=0 zero dart called the phase voltage. For generator and transmission lines phase voltage(їх three) are designated as follows: UA, UB, UC or Uf. The voltage phases of the drive are indicated as follows: Ua, Ub, Uc. The voltages between the two cobs of the generator phases (or the two cobs of the phases of the generator) or between the two line wires are called line wires and are used for the generator and the power lines: UAB, UBC, UCA, or Ul, for the voltage Uab, Ubc, Uca. Looking through the contours abn, bcn, can (Fig. 8.2) following another Kirchhoff law, the linear stresses are equal: UAB = UA - UBC = UB - UC (7) UCA = UC - UA ) a) stresses for symmetrical tension.

From Fig. 8.3a it can be seen that the “star” line voltages viperedzhaє "zirku" phase voltages by 30 °. Stars D nkb: UBC/2UB=30° UBC=Ö 3*UB, then. Ul=Ö 3*UФ (8) For availability neutral dart umova (8) vikonuetsya like when symmetrical, so i when asymmetrical adopter. In Fig.8.3b vectordiagram phase voltages and topographic diagram of linear voltages. Phase coefficients of tension coefficient equal: cos φа = Ra/Za; cos φв=Rb/Zb; cos φс=Rc/Zc (9) At more symmetrical: Ia=Ib=Ic=If=UF/Zf (10) cos φa= cos φv= cos φc=Rf/Zf Strum at the neutral wire IN=0, to that for connecting three-phase symmetrical installations (heating furnaces, dryers, electric motors and other symmetrical installations) a three-wire lance is installed. For osvіtlyuvalnogo navantazhennya nayavnіst neyavnіst drotu obov'yazkovo, oskolki mayzhe zavrіgaєsya zberіgaєsya asymmetries. At the neutral rod in the chotiriprovidnіy osvіtlyuvalnіy merezhі it is fenced in the installation of guards or vimikaciv, the shards when the neutral phase of the rod is turned on, the voltages can become irritable. In some phases, the voltage will be greater than the nominal, in others - less than the nominal. In both vipadkas, it’s possible to get out of the way. At whom the lansyug of zahisnoe zeroing is broken. The vector diagram of the voltage and strums with symmetrical active-inductive stress is shown in Fig. 8.4 Fig.8.4 With an asymmetric approach, for example: Za¹ Zb¹ Zc the sp_v_dnoshenie IL=IF is saved, and the sp_v_dnoshena Ul=Ö 3*UФ is destroyed. Fig. 8.5 shows a vector diagram with an increase in the drive for phase "a", then for Za For reactive tension, the sign + is for the inductive nature of the tension, the sign is for the eminent nature of the tension. The reactive tension of the triphasic lancer in the case of asymmetric tension is more: S = In case of symmetrical tension of the surface, that reactive tension in the primaries of the triphasic lancer is probably more favorable: S = Ö 3*UL*IL; P=Ö 3*UL *IL *cosφФ; Q=Ö 3*UL *IL *sinφФ Abo S=3SF = 3UФ*IF; P=3PF=3UФ *IF *cosφФ; Q=Ö 3*UL *IL *sinφФ EXPERIMENTAL TECHNIQUE. For robots, the calculation of electrical quantities is carried out for additional accessories without an intermediate assessment. Ammeters are installed on the stands to turn on the skin phase. For vimiryuvannya strum at the zero dart on the stands installed okremi prilad. Figure 8.8 shows the principle scheme of laboratory work. To terminals A, B, C and N, a voltage of 36 V of a three-phase step-down transformer is connected, connected behind the "spark" / "spark" circuit with a zero point with a voltage of 380/36 V. strum and tension. As a source of a three-phase lance, serve as a heating lamp with Unom = 36, Рnom = 40 W, switched on by toggle switches SA1-SA3. The change of heat is regulated by the number of turning on the heating lamps at the skin phase. Shaving the phase is activated by turning off the SA4 toggle switch. A short zamikannya is carried out by a path with a wire on the cob and the end of one phase only in a three-wire lance. Triphasic stake ceremony is carried out according to the scheme of the stand.

Fig.8.8 VIMOGY SECURITY PRACTI. Turn on the stand at the merezh only with the permission of the vikladach. Under an hour of work, the stand should not be touched by a clamp. Do not work on the daily repair work on the stand, about the inadequacy of the additional work of the vikladachs. Do not stick around lamps rozharyuvannya pіd hour and pіslja їх works. Do not flood the right stand without seeing it. ORDER VIKONNNYA ROBOTI Attach that attachment. The stand is equipped with a QS package vimic, Fig.8.8. Purpose of accessories: A4 – ammeter for vimir or strum in zero wire; A5, A6, A7 – amperemetry for vimir or strumu in phases a, b, c; V - voltmeter for measuring the line and phase voltages of the lance; Familiarize yourself with the laboratory stand. Find out vimikach, tumblers of additional ideas. Choose a scheme for setting up a target with a star with a zero dart. Mounting schemes are brought to the stand. Show the chosen scheme for rechecking the applicants or the laboratory assistant. Write down the technical data of the fittings that need to be fixed. Open the stand and install symmetrical phase shifting. The SA1, SA2, SA3 toggle switches are only partially switched on, the SA4 toggle switch at the external station can be switched on. For indications of ammeters at the phases, change at the equanimity of the strum in the phases, as well as at the presence of the strum in the zero droit. Change the phase and line voltages. Follow the advancement in a four-way lance in asymmetric modes, after doing the following: increase (change) the advancement in one of the phases (for example, “a”); those same have two phases; shaving one of the phases. Follow the three-way lancet, tobto without a neutral dart. To select the automatic switch QF4 for a zero-point lance, try the following: symmetrical orientation (just like point 3); increase (change) the advancement in one of the phases (for example, “a”); those same have two phases; short-circuiting of one of the phases. Vіdpovіdno up to these tables. 8.1 for all the results, use the vector diagrams of the stream and voltage. Zrobіt vysnovki schodo roboti for the form, induced by the laboratory robot №10 of the assistant. EXPERIMENTAL RESULTS. The robots carry out direct, one-time measurements, the accuracy of which is assessed by the accuracy class of the simulation (UФ, UL, UNn, IF, IL, IN). The result can be expressed by two numbers, for example: I=4.00 ± 0.05 A, de 4.00 A is the value of the simulated value, 0.05 A is the absolute error of the virus. To assess the accuracy of the minimum values ​​of UNn, INn, follow the formula of the perceptible error: d = K(XN/x) ; de K - class accuracy of the attachment; ХN – normative value of the variable value (upper scale of the fitting); x is the value of the modified quantity. Weekly electrical circuits must be carried out in accordance with GOST. Pobudov vector and topographic diagrams are carried out at the scale. POWER FOR SELF-TEST. What kind of meta robot and what kind of order її vikonannya? Draw a scheme for connecting all accessories. Indicate recognition of all accessories. Write the formulas for the connection of linear streams and voltage with their phase values ​​for symmetrical stress with a "star" being connected. How are the values ​​cos φa, cos φb, cos φc, PF, PA, PB, PC, P, Q, S determined? Let's talk about the order and vector diagrams of voltage and flow for active navigation. Yake recognition of a zero dart? In some ways, from a zero dart, does a strum flow and how does it manifest itself? Draw a scheme for setting up the “star” and turn on the fittings for adjusting the phase and linear jets, the jet at the neutral jet. Why not put a guard in the zero wire? Draw a vector diagram of the voltage and strums with an increase in the pressure of one of the phases of a chotiri-wire lance. Draw a vector diagram of the voltage and streaks with an increase in the voltage in two phases of a chotiripide lance. Draw a vector diagram of the voltage and strum when shaving one of the line wires at the chotyri wire lance. Literature Kasatkina A.S. Electrical engineering: assistant for universities / O.S. Kasatkina, M.V. Nemtsov. M: Vidavnichesky center "Academy", 2005. 542 p.

Three-phase tension and three-phase voltage increase star or tricoutnik. Z'ednannya with a star is shown in fig. 18.1.

The point of connection of all phases of the dzherel voltage is called neutral(otherwise zero) the dot dzherel that is indicated N. The start point of all phases of the advancement is called the neutral (or zero) point of the advancement and is assigned n.

The wire that brings the neutral points of the dzherel and the vanishing is called neutral(otherwise zero). Vіn takes care of the independent work of the phases of the lancer. So, as in one phase, there will be a change in the mode of work, two other phases of the “do not remember”.

Strum at the neutral wire will sound less, lower at the line wires, so the neutral wire is often thinner for the line wires. With symmetrical vanishing the strum at the neutral rod is equal to zero, then in such a situation (for example, when three-phase engines or furnaces are connected) neutral wire vzagali do not vicorist.

The neutral conductor is often grounded and grounded from it by the electrical installation housings (zahisne grounding).

The voltages are called phase voltages, because tse voltages of the phases are dzherel and navantage. The voltages are called linear, because tse voltage between the linear rods. Strumi є one-hour phase and linear, because tse one-hour stream of phases dzherela and navantazhennya, as well as streams in linear drots.

Let's look at the level that describes the camp of the analyzed lancer. Vіdpovidno to the 2nd law of Kirchhoff:

The link between the phase and line tension can be shown on the vector diagram (Fig. 18.2). From the first little one, you can see the relationship between the fluctuating values ​​of the phase and line voltages:

.

On three-phase vector diagrams, often put letters that match the points of the ate scheme. lancers, for example, A, B, C, N(Fig. 18.2). The number of letters needs to be understood as a designated point of the complex plane, which gives the electric potentials the Lantzug points A, B, C, N, which change according to the sinusoidal law..

Our vapad j N= 0, j A = u A j B = u B, j C = u C equal to that reaffirming the eligibility u AB= j A-j B. The stress arrow on the vector diagram is straight to the point IN to the point BUT, that scho vyhodit yak r_nitsya vektorіv ta .

Zvernemo respect for those who are viable to the same eve u AB= j A-j B arrow tієї w voltage u AB on the scheme, the lance for the designation is straightened out as a point BUT to the point IN.Tsya vіdminnіst go to that , what the arrows on the diagram indicate directly the calculation of the voltage and the stream, and the arrows on the vector diagrams show the images of the sinusoids on the complex plane.

Vіdpovidno to the 1st law of Kirchhoff , Tobto strum at the neutral drotі dorivnyuє sum strum at the linear darts. Tsey sv'yazok strum_v indications on the vector diagrams fig. 18.3-18.8.

Vіdpovіdno to іvnyan phases navantazhennya (for Ohm's law):

Such a connection of voltage and strum for the fluctuations of various pressures is shown in fig. 18.3 -18.8.

Vector diagrams of strums look at the examples of some specific types of advancement.

In the simplest form of symmetrical resistive voltage (so that if all three phases of voltage are the same resistors, as in the case of laboratory work No. 1, Fig. 18.3), the vector diagram of the streams and phase voltages looks like this, as shown in Fig. 18.4. Strum and voltage of the skin element of the tension shift in phase, which is why the vectors are straightened into one beat. The chinnі meanings of all three strums are the same, so the vectors and strums may have the same value. The sum of the phase strums is equal to zero, so the strum of the neutral drone is also equal to zero and there are no indications on the diagram.

For an asymmetric resistive bias (if all three phases of bias are resistors, but with a different support, Fig. 18.5), the vector diagram is shown in Fig. 18.6. Resistive drive is also called active. The vector that depicts the strum at the neutral dart, the other sum of vectors that represent the phase of the streak.

For asymmetric voltage, what is added up with a resistor at the phase a, active-semitic element in the phase b that of the active-inductive element at the phase c(Fig. 18.7), the diagram is shown in fig. 18.8. Main vіdminnіst vіd fig. 18.6 Pogaє at the phases of the phase jets according to the phase voltages.

Types of triphasic lancet tendencies are either active or active-inductive. At dosvidi No. 2 of laboratory work No. 3, a resistor and a capacitor are connected in parallel with active-switching voltages.

The active tension of the triphasic tension is higher than the sum of the tensions of the phases: . The tension of the phases can be measured by increasing the wattmeter according to the scheme of fig. 18.9. Leather wattmeter of inclusions on the phase voltage and phase jet of a dual-phase input. In case of a symmetrical voltage, it is possible to reduce the tension of more than one phase and multiply it by three (when the neutral voltage is present, the voltage winding is connected to the neutral point of the voltage).