The three-phase system of the phase voltage is asymmetric. Asymmetric priming
With symmetrical vanishing
U a = U in = U h = U BUT = U IN = U W = U f
Ia = iv = ic = I
The sum of the mittiev values of the streams of all three phases is geometric; the sum of the vectors of these streams equals zero (Fig. 4).
The strum at the zero dart at chotiriprovidnіy zіrtsі will be daily. Also, with a symmetrical approach, there is no need to use one connection.
Asymmetric vanity.
Vipadu has a non-symmetrical vanity Z a Z b Z h .
Non-symmetry can be a violation of heterogeneity and unevenness of ambition.
Non-symmetrical vanity, z'ednane "zirkoy", zvvychay podklyuchayut for chotiriprovidnoy scheme, tobto. with a zero dart, shards for the presence of a zero dart, which may be a small opir, asymmetrically, the ambition is not to produce a significant change phase voltage. It is possible to understand from some close proximity that the phase voltage is filled with the same, as for a symmetrical tension.
U a = U b = U c = U BUT = U IN = U W
.
The zero dart flows through the strum I o
A vector diagram with a non-symmetric phase bias (prevention is active, non-symmetry is created by uneven bias) with a zero drome is shown in Fig. five.
The presence of a zero droop with an asymmetric vanishing disrupts the normal operation of the installation.
The phases of the stream change and are restored such that the sum of them reaches zero. As a result of this, the symmetry of the phase voltages is observed: the phase with a smaller support appears under a reduced voltage, and with a large support - under a movement, against a normal one.
A vector diagram for the presence of a zero dart is shown in fig. 6.
Pobudov's diagrams start from the constant tricot of linear voltages.
Zero generator ( N) is considered to be the center of gravity of trikutnik, tk. phase voltage of the generator is symmetrical. Zero point of interest ( n) is defined as follows: from points BUT the size of the compass, equal to the scale of the magnitude of the variable phase stress of tension U but squirm. So zasіchki vykonuyutsya from the point IN compass design U in, from points W- by design U h. The point of the crossbar is zasіchok i є zero navantazhennia. Alternating the zero point with the phases of the generator (i.e. BUT, B, C), we will induce phase voltage U but , U in , U h. Fallow, according to the nature of the quest, conduct vectors and strums. On fig. Figure 6 shows a vector diagram of the non-uniform active drive.
Vіdrіzok Nn= U 0 - the voltage of the neutrals used can either be measured with a voltmeter or is secured by the formula
,
de 
- complex of the values of the phase voltage of the generator;
Y a , Y b , Y h- Complex conductivity of the phases of navantage.
When the voltage is displaced by the neutral phase, the voltage of the receiver can be protected by the formulas:
,
,
.
In the laboratory robot, one can see some fluctuations in asymmetric vanishing, shaving the skin and shortly flickering the phase of the priming.
At the time of the shaving of the phase BUT without zero voltage with equal active supports of the two other phases: 
,
;
;
Vector graphics are shown in fig. 7.
Phase short flicker BUT:
U a = 0, 
,
,
.
Vector graphics are shown in fig. 8.
The active tension of the triphasic strum in the case of asymmetric navantage of the phases is equal to the sum of active tensions of all phases.
Scallops with symmetrical phases and symmetrical voltage systems U a
=
U b
=
U h
=
U f ;
U AB
=
U ND
=
U SA
=
U L ;
cosφ a
= cosφ b
= cosφ c
=
cosφ f, then active tension triphasic struma is more expensive 
.
So with the z'ednanny "zirkoy"
;
, .
Laboratory robot 8
TRIPHASIA LANTSYUGA.
Z'EDNANNYA NAVANTAZHENNYA ZIRKOYA
Meta work: vivchit lance of a three-phase strum when z'ednanny priymacha zirkoy in symmetric and asymmetric modes. Designate the role of the neutral (zero) dart.
BASIC CONCEPTS
A three-phase system of alternating streams is a combination of three single-phase electric lances, which have sinusoidal EPCs of the same frequency, disruptions behind the phase for 1/3 of the period and the creation of a gale of electrical energy. The triphasic system was found in all details by the talented Russian engineer 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 the open space one by 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. The generator phases are strictly assigned and are changed in the hour of the EPC phases, that is, in the blackness of the EPC maxima: the first phase of the A phase, then after 1/3T of the phase і through 2/3T of the Z phase. Such a sequence of drawing is called a straight line.
Mittevi EPC values three-phase windings equal generator:
eA=Emsinwt eB=Emsin(wt-2/3p) eC=Emsin(wt-4/3p) (1)
Figure 8.1 shows the graphs of the math and the values of the phase EPCs and three vectors of similar values of the EPCs.
As can be seen from Fig. 8.1, the sum of the calculated values of the EPC at any time is equal to zero, then, the geometrical sum of the variable values of the phase EPC of the generator is also equal to zero:
EA+EB+EU=0
As shown in Fig. 8.1, depending on the complex value of the EPC of a three-phase generator through the same for all three phases, the same value of E, then
EA=E∙ej0
EB=E e-j2/3p (3)
EU=E e2/3p
For the adoption of a three-phase system, it is necessary to follow the same order as the phases of the priymacha, sound, for the scheme "star" or "trikutnik".
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, with a certain end of phases, 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).
See what's 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 wires equal to zero, it is possible to designate a stream of three phases of the generator:
I A= E A/ZA; I B= E B/ZB; I C= E C/ZC. (4)
Strumi I A, I b, I C
linear (IL). Strums that flow at the phases of the generator and the phases of the input are called phase streaks (If). For z'ednannya "zirkoy" linear streams rіvnі fazim, tobto
IL=I f (5)
Strum at the neutral dart according to the first law of Kirchhoff is more advanced:
I N= I A+ I B+ I C(6)
Acceptances with the same support of all three phases Za=Zb=Zc are called symmetrical. With symmetrical acceptance I A= I B= I C i strum at neutral dart IN=0
The voltage between the cob and the end of the phase of the generator (or the phase of the voltage) or the voltage between the linear and zero dart is called the phase voltage. For the generator, those lines of power transmission phase voltages (їx three) are assigned 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) behind another Kirchhoff law line voltage equal:
U AB= U A- U B
U BC= U B- U C(7)
U ca= U C- U A
Scabrous tsim spіvvіdshennyam, pobudёmnu vector diagram (Fig. 8.3a) voltage for symmetrical navntazhennia.
From Fig. 8.3a it can be seen that the "mirror" of the line voltages is the "mirror" of the phase voltages by 30 °. Sounds from Dnkb:
UBC/2UB=30° UBC=Ö3*UB, then Ul=Ö3*UФ (8)
When present neutral dart umova (8) vikonuetsya like when symmetrical, so i when asymmetrical adopter. In Fig.8.3b, a vector diagram of phase voltages and a topographic diagram of line voltages are shown.
Phase coefficients of tension equal:
cos φа = Ra / Za; cos φв=Rb/Zb; cos φс=Rc/Zc (9)
de φа, φв, φс kuti zsuvu phases between phase voltages and phase streams.
With symmetrical vanishing:
I a= I b= I c=If=UФ/ZФ (10)
cos φа= cos φв= cos φс=Rf/Zf
The jet at the neutral rod IN=0, so for the connection of 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
http://pandia.ru/text/78/082/images/image007_97.gif" height="22">.gif" width="229">.gif" height="135">
http://pandia.ru/text/78/082/images/image039_17.gif" width="13" height="18">.gif" width="115" height="191"> Ic Ib
http://pandia.ru/text/78/082/images/image046_12.gif" width="10" height="13"> Ua
Ia Uc = Uca Ub = Uab
http://pandia.ru/text/78/082/images/image050_10.gif" width="116" height="59"> Ic I b
http://pandia.ru/text/78/082/images/image052_10.gif" width="11" height="20"> Uc Ubc Ub
Rice. 8.5 Small 8.6
 |
http://pandia.ru/text/78/082/images/image058_10.gif" width="117" height="59"> n
http://pandia.ru/text/78/082/images/image061_9.gif" width="11" height="14"> Ic Ib
http://pandia.ru/text/78/082/images/image068_9.gif" width="228"> Uc n1 Ub Ubc
The tightness of the phase is active when the “star” is forced, for example, phase a, more:
The one is active reactive sweating priymachi v triphazny lancet with asymmetric navantage rіvnі:
http://pandia.ru/text/78/082/images/image070_9.gif" width="83" height="35">
In case of symmetrical tension of the skin, active and reactive tension in the primaries of the triphasic lancelet is likely to increase:
S \u003d Ö3 * UL * IL; P=Ö3*UL *IL *cosφФ; Q=Ö3*UL *IL *sinφФ
Abo S \u003d 3SF \u003d 3UФ * IF; P=3PF=3UФ *IF *cosφФ; Q=Ö3*UL *IL *sinφФ
EXPERIMENTAL METHOD.
At the robotic world electrical quantities go for help
attaching an unbiased 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. In Fig. 8.8 it is pointed principle diagram laboratory work.
To terminals A, B, C and N, a voltage of 36 volts of a three-phase step-down transformer is connected, connected behind the “sirka” / “sirka” circuit with a zero point with a voltage of 380/36 V.
Attachments A1..A7 and V phase strums that voltage. 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.
4. Do not stick around the lamps rozharyuvannya pіd hour and pіslja їх work.
5. Don't leave the right stand unattended.
ORDER VIKONNNYA ROBOTI
Fit that fit.
The stand is equipped with a QS package vimikach, Fig.8.8.
Purpose of accessories:
A4 - ammeter for measuring the strength of the struma at zero droit;
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;
1. Get familiar with the laboratory stand. Find out vimikach, tumblers of additional ideas.
2. Choose a scheme for targeting the star with a zero dart. Installation diagrams Dosvidu pointed at the stand. Show the chosen scheme for rechecking the applicants or the laboratory assistant.
3. Write down the technical data of the installed accessories. 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. Write down the data at the table. 8.1
Table 8.1
|
venture | Vimiryano | Calculated |
||||||||||||
Continue the adventure at the chotiripide lancet in asymmetric modes, robyvshi so dosledi:
those same have two phases;
shaving one of the phases.
Follow the three-way lancet, tobto without a neutral dart. For whom to turn automatic wimicach QF4 in lances of zero value and try the following:
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
behind the form, induced by the laboratory robot No. 10
currying.
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.
Record the results of vimiriv at the table. 8.2.
Table 8.2.
Vimirians value in alone | |||
Sunday electric circuits get through to GOST.
Pobudov vector and topographic diagrams are carried out at the scale.
POWER FOR SELF-TEST.
1. What is the meta robot and what is the order of vikonannya?
3. Write the formula for the connection of linear streams and voltages with their phase values for symmetrical stress with a "spark" being connected. How are the values cos φa, cos φb, cos φc, PF, PA, PB, PC, P, Q, S determined?
4. Telling about the order and the vector diagrams of the voltage and the stream for active navigation.
5. How to recognize a zero dart? In some ways, from a zero dart, does a strum flow and how does it manifest itself?
6. 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.
7. Why in zero wire no way to put a guard?
8. Draw a vector diagram of the voltage and streaks with an increase in the stress of one of the phases of the chotiripide lance.
9. Draw a vector diagram of the voltage and strums with an increase in the voltage in two phases of a chotyri-like lance.
10. Draw a vector diagram of the voltage and streaks when one of the linear darts is shaved off a chotyri-wire lance.
Literature
1. Kasatkina: assistant for universities / , M.V. Nemtsov. M: Viewing center "Academy, 20s.
Preparation for work | 1 academic year |
Vikonanny roboti | 1 academic year |
Processing of the results of the experiment and registration | 1 academic year |
Sound of laboratory work | 1 academic year |
Laboratory robot 9
TRIPHASIA LANTSYUGA.
Z'EDNANNYA NAVANTAZHENNYA TRIKUTNIKOM
Meta robotic: win the lance of a triphasic struma when using a tricot in symmetric and asymmetric modes.
BASIC CONCEPTS.
The last of the phases in trikutnik is called the same way, when the cob of one phase is connected with the end of the other phase, the ear of the other phase is behind the end of the third phase, the ear of the third phase is connected with the end of the first phase. Linear darts are brought to the high points of the cobs and ends. Two ways of graphical representation of the chain behind the trikutnik scheme are shown in fig. 9.1a and 9.1b.
http://pandia.ru/text/78/082/images/image076_8.gif" width="486" height="229 src=">
It can be seen from the diagram that if the supports of the linear rods are equal to 0, then the phase voltage is equal to the voltage of the generator, then UФ = UL. The phase of the voltage with a tricot is 1.73 times greater, the lower phase of the voltage with a circle.
Let's take the mentally positive direct lines of the linear voltage (Fig. 9.1) to give the mentally positive straight lines; strumi at the phases equal:
Iab=U ab/ Z ab; I bc= U bc/ Z bc; I ac= U ac/ Z ac (1)
For knots a, b, c (Fig. 1) linear streams according to the first Kirchhoff law are equal:
I A= I ab- I ca;
I B= I bc-Iab; (2)
I C= I ca- I bc;
For symmetrical aiming Z ab= Z bc= Z ca phase jets I ab= I bc= I ac may still cut to phase voltages.
In Fig.9.3, the vector diagrams of the voltage and the streams are induced with a symmetrical bias, connected by a tricot (phase bias is active - inductive).
http://pandia.ru/text/78/082/images/image080_7.gif" height="17 src=">
From the diagrams, one can see that with a symmetrical vanishing, there is one thing between phases and linear streams:
Rozrahunok strumiv lead for one phase:
IФ=UФ/ZФ and IЛ=Ö3*IF
In the case of an asymmetric bias, for example, an increase in the bias in the phase ab (Zab
When the support of the “bc” phase is increased to inconsistency, which shows the shaving of the phase line, the strum at nіy Ibc=0 and equal (2) will be recorded at the sight:
I A= I ab- I ca;
I B=- I ab; (3)
I C= I ca;
The vector diagram of this trend is given in Fig. 9.5
At the time of shaving one of the linear darts (for example, darts A), the lancet becomes single-phase with two parallel needles, which are under the pressure U b.c.
so yak Z ab= Z bc= Z ca, then I ca= I ab=0.5 I bc; I b= I bc+ I ab; I c=- I b.
The vector diagram for the shaving of the linear phase is given in Fig. 9.6
http://pandia.ru/text/78/082/images/image089_5.gif" width="87" height="13 src="> Ibc
http://pandia.ru/text/78/082/images/image093_5.gif" width="85" height="35">
In case of symmetrical tension, that reactive tension of the primaries of the triphasic lancelet is active:
P=3Pf=3Uf*If*cosφФ
Q=3Qf=3Uf*If*sinφФ
P=Ö3UL* IL*cos φФ
Q=Ö3UL*IL*sin φФ
Exterior tightness of the triphasic lancet with symmetrical thrust:
S=3SF or S=Ö3*UL*IL
Exterior tightness of the triphasic lancet in case of asymmetric tension:
EXPERIMENTAL METHOD.
Description of the work to the stand to marvel at the spread of the front work (No. 8)
Shaving of the phase zdіysnyuєtsya vіd'єnannym priymach at point a, b or c. Vimiryuvannya prugi pass through the voltmeter V.
VIMOGI SECURITY PRACTI.
Marvel at the latest division of laboratory work (No. 8)
ORDER OF VIKONNNYA ROBOTI.
Fit that fit:
The description of the robot and the stand is given at the front laboratory robot (No. 8).
Purpose of accessories:
A1, A2, A3 - ammeters for measuring line streamers;
A4, A5, A6 - ammeters for testing phase streams;
V - voltmeter for measuring the phase and line voltage;
1. Familiarize yourself with the laboratory bench, find out the vimikach tumbler, the toggle switches - the inclusion of additives
2. Choose a scheme for setting up a profit from a tricutnik. The assembly diagram is shown on the stand. Show the scheme of re-verification of the applicant to the laboratory assistant.
3. Write down the technical data of the installed accessories.
4. Increase the stand and install symmetrical phases. Toggle switches SA1, SA2, SA3, after the introduction of the switch, may be on or off. Toggle switch SA4 at the exit station can be switched on.
For the indications of ammeters, switch to the equanimity of the streams at the phases and linear droths. Data vimiryuvan strumiv and the voltage of u 9.1. In the column “Navantage mode” enter the mode of the navvantage (symmetrical or non-symmetrical).
5. Follow the same steps for non-symmetrical vanishing:
Increased vanishing in one of the phases
Increased vanishing in two phases
Shaving the phase dart
Shaving the line dart
Table 9.1
|
venture | Vimiryano | Calculated |
||||||||||
EXPERIMENTAL RESULTS.
In the robotic processing of the results of the experiment, it is carried out in two stages up to the second division of the frontal work. To build up the visnovkas according to the form, induced in the laboratory robot No. 10 of this ceramics.
POWER FOR SELF-TEST.
1. What are the goals of the robot and the order of vikonannya? Please explain for the scheme of laboratory work.
2. Draw a diagram for connecting all accessories. Indicate recognition of all accessories.
3. Write the formula for the connection of linear streams and voltages with their phase values for symmetrical and asymmetrical voltages for symmetrical and asymmetric voltages for tricutniks. How are the phases of tightness, tightness of the entire triphasic lancet determined?
4. What is the order of the vector diagrams of voltages and streams for active stress?
5. Draw a vector diagram of the voltage and strums with the increase in stress in one of the phases.
6. Draw a vector diagram of the voltage and strums with the increase in voltage in two phases.
7. Draw a vector diagram of the voltage and streaks when the phase dart is cut.
8. How many times do the phases and linear streams and voltages change when the symmetrical tension changes from the “star” to the “trikutnik”? Vіdpovіd explain on the butt of the data, otrimanih at the end of the adventure, put into the "star" of the front laboratory work.
9. How many times does tightness change when switching schemes of vanishing from “star” to “trikutnik”? Please explain on the butt of data taken from the front laboratory robot
symmetrical vanity.
10. Induce the vector diagram of the strum and the voltage when shaving the line dart.
Literature
1., Nemtsov. Navch. for universities. - M: Vishcha. school, 2000. - 542 p.
Hour, introduction to the laboratory work.
Preparation for work | 1 academic year |
Vikonanny roboti | 1 academic year |
Processing of the results of the experiment designing a star | 1 academic year |
Sound of laboratory work | 1 academic year |
Laboratory robot №10
VIVCHENNYA TRIPHASE LANTSYUG WHEN Z'EDNANNI PHASES OF THE RECEIVER ZIRKOI AND TRIKUTNIK
Meta roboti: vivchity lanceug triphasic struma when the phases are connected, the first one is followed by the “star” scheme, then by the “trikutnik” scheme in symmetrical and asymmetric modes.
Basic understanding.
Marvel at the results of the division of laboratory experiments No. 8 and No. 9.
Experimental methodology.
Laboratory work is carried out on the stand, a description of which is placed on the side of the 9th helper. For vikonannya work at the head of the group of vikladach form a couple of brigades (2.4 or 6). With which unpaired team, the team will hit the back of the robot No. 8, and the guys - No. 9. Then the brigades exchange missions, and already at the chosen stands they win the work in the same way: unpaired No. 9, men - No. 8. The order of setting the doslids in laboratory robots No. 10 is the same as in laboratory robots No. 8 and No. 9, but after the short scheme. There are 3 three-phase lancets: 1. Chotiriprovidny lancet at the beginning of the phases of star attraction; 2. Tri-conductive lancet when the phases of star attraction are connected. 3. Three-way lancet when the phases of navantage are connected to the tricot. For the skin lancet, there are 2 modes of vanishing: a) symmetrical; b) asymmetrical (for example, an increase in vanishing in one of the phases). In this rank, 6 doslidiv are victorious. Vymogi bezpeka pratsі so themselves, like in vіdpovіdny razdіlі laboratory work №8.
Order of vikonannya roboti:
1. Get familiar with the laboratory stand. Know the wire rope, toggle switches for switching on the auxiliary switches (heating lamps) SA1 .... SA3, how to turn on the switch, switch
phase SA4, which may include inclusions. Ammeter A1, A2, A3,
are indicated for the elimination of linear strums during the closing phases of the priming tricot. A4 ammeter - for vimiryuvannya strum in the zero dart of a chotiripid lancet. Ammeters A5, A6, A7 - for the simulation of phase streams, as when the phases of the current are connected, for the "star" scheme, so for the "trikutnik" scheme. For vimiryuvannya phase and line voltages on the circuit є voltmeter 50 volts. To vimiryuvannya voltage between the neutrals of the generator and voltage on the stand є voltmeter 15 volts.
2.Choose the scheme of proof. Unpaired brigades choose the scheme, for which phase the priymacha follows the “zirka” scheme, and the guys follow the “trikutnik” scheme. Mounting diagrams for guidance on the stands.
3. Unpaired brigades tick the robot in this order:
A. dosledzhuetsya 4-wire lansyug for the "zirka" scheme
Dosvid 1: more symmetrical ambition. In Table 1 of laboratory work No. 8, the indications of ammeters and measurements of linear and phase voltages are recorded.
Behind the results of the vimiryuvannya strumіv i naprug fight vysnovok, the form of which is induced in the end of the division.
Dosvid 2. Asymmetric interest. Then after the order, one of the toggle switches SA1 ....
B. Doslіdzhuєtsya 3-wire lansyug when the phases of priymach are connected to the “star”
Dosvid 3. More symmetrical. For this, turn off the toggle switch, which will turn on the automatic switch QF4, turning on the null wire itself. Write down the indication by attaching the table, and in the windows, write down the results of the guard.
Dosvid 4. Non-symmetrical vanity. The same toggle switch is turned on, which has 2. At the table, the indications of all accessories are recorded, and the results of the warnings are recorded in the windows.
Dosvid 5. Symmetric focus. Tumbler SA1. . ……..SA3 off, SA4 toggle switch on.
Turning on the stringing vimikach SA, record the readings of the ammeters and voltmeters in the table. 9.1.
After whom is recorded technical characteristics all zastosovuvanih priladіv.
Reading brigades carry out follow-ups in this order: Dosvid 5; Dosvid 6; Dosvid 1; Dosvid 2; Dosvid 3; Dosvid 4.
It is necessary to conduct a tax audit before the end of the data and write down the results of the tax audit to the table next to the “calculated” column.
For all the results, use the vector diagrams of the voltage and the stream at the scale on a millimeter paper or a paper in a cage.
Whiskers shodo roboti.
1. Z'ednanny phases of the catch at the "star".
BUT.3-phase, 4-wire lance (with zero drotom).
Dosvid 1. With a symmetrical navantage of a 3-phase, 4-wire lancet, when the phases of the receiver are connected to the “star”, we have installed:
voltages on the phases of the priymach __________ beside yourself, the lamps burn with ___________ bright
(equal or not equal) (equal or different)
line voltages ____________ phase at _________ times,
(more, less) (number)
what is considered in the theoretical. on the________%
Dosvid 2. With asymmetric navantage in a 3-phase, 4-wire lancet, with the connection of phases, the following was taken away from the “star”:
Stresses on the phases of the primach ______________________________________________
(changed chi nі, equal chi not equal among themselves)
Lamps burn _____________________________ yaskravistyu
(With the same or different jaskravist)
Line voltages _______________________ phase at _______ times
(more, less) (number)
In this way, the presence of the 4th droid ensures the safety of ________________ phase voltages
and allow you to include up to such a measure ___________________________________________
(a) symmetrical, b) non-symmetrical, c) that symmetrical. that is unbalanced. vanity)
B. 3-phase, 3-wire lance. Z'ednanny phases of the catch at the "star".
phase voltages on the voltage ______ lamps burn out of ____________ light
(changed chi nі) (same chi different)
Zero wire with symmetrical vanishing
(obov'visky or neobov'viscous)
With asymmetric navantage in a 3-phase, 3-wire lance, with the connection of phases at the “star”.
Voltage phase on the voltage ___________________ lamp brightness _________________
(same or different) (same or different)
Asymmetric installation in 3-phase, 3-wire lance turn on __________________
(possible, not possible)
2. Z'ednannya phases of priymach to trikutnik.
When the phases of the priming are connected, the following is established for the "trikutnik" scheme:
Voltage phases ______________ at the same mode for the “star” scheme
(increased, changed)
the lamps burn ______________ brilliance and ___________________ at the povіvnіnі zі scheme "zіrka"
(with the same or different) (with a red or weak)
Linear streams of __________ phase at ______ times, which are considered theoretical by ____%
(more or less)
Stresses on the phases of prevantage ____________________________________________
(changed, increased, did not change)
The lamps burn _z _____________________ brightly
(same, different)
In this rank, behind the "trikutnik" scheme, you can turn on
Nancy.
(a) symmetrical, b) non-symmetrical, c) both symmetrical and non-symmetrical)
A summary of the results of the experiment div. vidpovidny razdil lab. Rob. No. 8.
Food for self-verification divas. at vіdpovіdnih razdіlakh lab. work No. 8 and No. 9.
Literature:
The same as in laboratory robot No. 8.
An hour of introduction to the laboratory work
Preparation for work | 2 academic years |
Vikonanny roboti | 2 academic years |
Operational results | 2 academic years |
Z'ednannya phases of the generator and priymacha trikutnik
At the end of the life of a tricutnik (Fig. 3.12), the end X of one phase is connected with the ear of the other phase, the end of Y of the other phase is with the ear of the third phase, the end of the third phase Z is with the ear of the first phase A. Ear A, B i From the phases, three darts are connected for help to the primaries.
Z'ednannya phases dzherela closures trikutnik is possible with a symmetrical EPC system, so
A + B + C = 0.
Yakshcho zadnannya windings trikutnik incorrectly vikonano, tobto. at one point, connect the ends or the cob of two phases, the total EPC in the circuit of the tricutnik winds up at zero and a great stream flows through the windings. Tse emergency mode for life is unacceptable.
The voltage between the end and the cob of the phase when connected with a tricot is the same as the voltage between the line wires. Therefore, when connected with a tricot, the line voltage is equal to the phase voltage.
As an unreliable support for line wires, the line voltage of the lifeline can be compared to the line voltage of the life line: U ab = U AB, U bc = U BC, U ca = U CA. In phases Z ab , Z bc , Z ca , the phase streams ab , bc і İ ca flow through. The positive direction of the phase voltage Ú ab , Ú bc and Ú ca is driven by the positive direction of the phase jets. Smart positive direction of the linear streams A, B and C was taken as a life expectancy before priming.
On the vіdmіnu vіd z'єdnannya zіrkoy vіdnіnі strikutnikom, phase strumi not equal liniynym. Strumi at the phases of the match are assigned to the formulas
İ ab = Ú ab / Z ab; İ bc = Ú bc / Z bc; İ ca = Ú ca / Z ca.
Linear streams can be assigned to the phase ones, aligning with the first Kirchhoff law for knots a, b and c (Fig. 3.12)
The left and right parts of the equal system, (3.20), are taken
İ A + İ B + İ C = 0,
tobto. the sum of complexes of linear streams is equal to zero, both for symmetric, and for non-symmetric vanishing.
With symmetrical vanishing
Z ab= Z bc = Z ca= Z e jφ ,
tobto. Z ab = Z bc = Z ca = Z, φ ab = φ bc = φ ca = φ.
Since the linear (stink of the phase) voltages U AB, U BC, U CA are symmetrical, then the phase jets are symmetrical system
İ ab = Ú ab / Z ab; İ bc = Ú bc / Z bc; İ ca = Ú ca / Z ca.
The absolute values of them increase, and the destruction in phase is equal to 120°.
Linear streams
İ A = İ ab-İ ca; İ B = İ bc - İ ab; İ C = İ ca - İ bc;
they also establish a symmetrical system of streams (Fig. 3.13, 3.14).
On the vector diagram (Fig. 3.14), the phase jets show the phase voltage on the coil φ (note that the phases are inductive, so φ > 0°). It is accepted here that the voltage U AB is zero phase. From the diagrams it is clear that there could be a linear strum larger than a phase one at a time. Linear strum A is in phase with the phase strum ab at the corner of 30 °, at the same corner it is B in Bc, C in İ ca .
In this way, with the tricot, the value of the linear struma, which is greater, with the symmetrical tension, is many times greater dignified phase strumuta U L = U F; I L \u003d I F.
In case of equal phase advancement, the development of a three-phase lancet lancet with a tricot can be brought up to a development of one phase.
Phase voltage U Ф \u003d U L. Phase stream I Ф \u003d U Ф / Z Ф, linear stream I L \u003d I Ф, cut zsuvu in phase φ \u003d arctg (X Ф / R Ф).
In a steep slope with asymmetric vanishing Z ab ≠ Z bc ≠ Z ca. Sound out blaming when eating food three-phase mesh single-phase receivers. For example, for the purpose, fig. 3.15, the phases of strumi, kuti zsuvu phases and phasic tension will be different in the wild phase.
Vector diagram for vipadku, if phase ab є more active, In the bc phase it is active-inductive, and in the ca phase it is actively-dismissive induced in fig. 3.16 topographic diagram - in fig. 3.17.
Pobudov’s vectors
İ A = İ ab-İ ca; İ B = İ bc - İ ab; İ C = İ ca - İ bc.
In this way, in case of non-symmetric orientation symmetry of the phase streams ab , b , ca is destroyed, then the linear streams A , B , C can be assigned only as a rozrachunk for the vision-guided lines (3.20) or as a graphical way vector diagrams(Fig. 3.16, 3.17).
An important feature of the phases priming with a tricot is those that, when changing the support of one of the phases, the operating mode of the other phases is left unchanged, because the linear voltage of the generator is constant. Change only the stream of this phase and the line stream at the wires of the line, connected with the phase cycle. To this reason, the scheme of the tricoutnik is widely used for the inclusion of a non-symmetrical vanity.
When expanding for asymmetric navantage, the values of the phase streams ab , bc , ca and the disruption of the phases ab , bc , ca are assigned to the cob. Then we appoint linear streams for additional help (3.20) complex form or for additional vector diagrams (Fig. 3.16, 3.17).
64 electric lansyug behind the schemes "zirka" and "trikutnik"
In electrical and electronic outbuildings, the elements of the lancer follow the brukivka (Fig. 1.12). Supports R 12 , R 13 , R 24 , R 34 are included in the shoulders of the bridge, diagonal 1-4 of the inclusions of the core of life from EPC E, another diagonal 3-4 is called the bridge diagonal.
 Rice. 1.12 |  Rice. 1.13 |
To replace the "zirka" scheme with an equivalent tricot, it is necessary to loosen the tricot support:
; 
; 
.
After carrying out the conversion (Fig. 1.13), it is possible to calculate the value of the equivalent support of the bridge circuit (Fig. 1.12)
.
With different connection schemes for three-phase extensions zahisnogo inclusion one-hour protection of single-phase triphasic sleepers. Zero and grounding tires for this circuit will be connected. With this type of connection, a lichilnik of electric energy is installed between the outhouse of the water connection and the automatic input switch.
65 Emergency modes triphasic lanceug
when z'ednanny navantazhennya on zіrku
Emergency modes that are to be blamed for short hums at the venture
or in lines and shaving wires. Let's call on some typical emergency
