7 Methods of implementation of laboratory work

7.1 To the point 6.1. Program and order of study of theoretical questions.

To study setting, features of structural, functional, circuit technology construction of the guided and out of control rectifying installations and processes of their functioning on materials of this laboratory work and recommended literature [2.1.2.5]. To study the features of circuit technology execution and functioning of laboratory model (см. of разд. 3). To get for a teacher control questions on the studied material and to prepare answers on them. To specify for a teacher a form and volume of their presentation in a report.

NOTE. Further implementation of laboratory work is shut out without permission of teacher. By an obligatory condition to admittance for implementation of work there is getting a clear idea of features of circuit technology execution of laboratory model (см. of разд. 3).

7.2 To the point 6.2. Research of the guided rectifiers - monophase однотактного at active (k = 1) and inductive(with the additional diode of VD1 and without him) character of loading and three-phase однотактного at active (k = 3) and inductive(with the additional diode of VD1 and without him) character of loading.

Providing of the required chart (см. рис. 3.2 and 3.3) of research (monophase and three-phase однотактных charts of the guided rectifiers with active and inductive character of loading) is carried out by means of switch of choice of research (см. рис. 3.1) chart.

For providing of the required parameters of elements of chart and modes of operations of the investigated rectifier the buttons of fast access of "G1" can be used, "ТV1", "СУ", "L1", "SW1", "SW2", "Rн" - (см. рис. 3.1).

7.2.1 To the point 6.2.1. Research of external (loading) descriptions of the guided rectifiers.

External description of Uн = f(Iн) is dependence of tension on loading from the current of Iн of loading, which passes through loading. In hired external descriptions of the guided однотактных rectifiers are investigated - monophase for active (k = 1) and inductive(with the additional diode of VD1 and without him) character of loading and three-phase for active (k = 3) and inductive (k = 4 - with the additional diode of VD1 and without him) character of loading.

Gradually increasing the current of Iн of loading by a change are adjustings of resistance of Rн from the mode of idling at Iн = 0 to the maximal value, to fix 5.7 his values in all turn-down of current of loading, evenly breaking up a range measuring. To measure here value Iн, Rн, Iа, Uа, Uн. To bring set values in a table. 7.1 (k), where k is a variant of chart of rectifier.

The methods of determination of external description following:

• by means of switch of choice of research (см. рис. 3.1) chart to choose the variant of chart of rectifier - "Monophase with R - loading" (k = 1), "Monophase with L -нагрузкой " (k = 2), "Three-phase with R - loading" (k = 3), "Three-phase with L - loading" (k = 4);

• to edit the parameters of source of G1 (phase tension of UА = UВ = UС = UG1 is Nome, working frequency of fc = fc nomas );

Table 7.1(k) are Results of researches

№ measur п/п	Experienced data					Calculation data
	Rl, Ohm	Il, A	Ul, B	Uа, B	Iа, A	ΔUl, B	ΔIl, A	rв, Ohm	S2, ВА	Pн, W	K2
1 2 …

• to edit the parameters of transformer of ТV1 : to set the necessary coefficient of transformation of n12 = n12 nomas and pure resistance of r2 = r2 nomas of secondary обмоток of transformer of ТV1 (ra = rb = rс = r2 Nome);

• to edit the parameters of throttle of L1 : to set the basic value of inductance of throttle of L1 = L 1ном;

• to edit the parameters of chart of management СУ : to set the basic value of adjusting (α = α Nome) corner α; to make sure, that the output signals of phase are included and (for monophase charts) and phases and, b, with (for three-phase charts);

• to disconnect loading, transferring the switch of SW1 in the broken a secret non-conducting state;

• to begin a design, pushing the button "Start";

• to take statements of voltmeters of PV1, PV2 accordingly tensions of U2 = Uа secondary puttee of transformer of ТV1 of phase and and Uн хх are tensions of idling on the output of rectifier. To bring a result in a table. 7.1(k);

• to connect resistance of Rн of loading, transferring the switch of SW1 in the reserved conducting state;

• changing resistance of Rн of loading (using the movable indicator of "Rн" - см. рис. 3.1) from a minimum (maximum) to the maximum(for example, Rн = 1, 2, 5, 10, 25, 50 and 100 Ohm), to take statements: voltmeters of PV1, PV2 - accordingly tension of Uа of phase and transformer of ТV1, Uн is tension in the chain of loading of rectifier; ammeters of PА1, PА2 - accordingly current of I2 = Iа, consumed from a phase and, and current of Iн in the chain of loading of rectifier. To bring a result in a table. 7.1(k);

• on results research to build external descriptions.

• For inductive character of loading of rectifier (k = 2) to execute researches for two variants: for monophase однотактного with the additional diode of VD1 (thus the switch of SW2 it is necessary to transfer in the reserved conducting state) and without the diode of VD1 (SW2 is transferred in the broken a secret state) and for a three-phase однотактного rectifier (k = 4 with the additional diode of VD4 and without him).

7.2.2 To the point 6.2.2. Determination of output resistances of the guided rectifiers.

Output resistance of rectifier is determined on the basis of the got results of measuring п. 7.2.1 (see a table. 7.1(k)) on a formula

r_в = U_н / I_н ;

U_н = U_{н max} – U_н; (7.1)

I_н = I_{н max} – I_н,

where Uн max, Iн max - see maximal values accordingly of tension and current of loading to the table. 7.1(k).

7.2.3 To the point 6.2.3. Determination of the percent lowering of output tensions of the guided rectifiers.

Percent lowering of Uн% of output tension of rectifier in transition from idling with tension of Uн хх to the nominal loading with output tension of Uн of nomas determined in a kind

. (7.2)

7.2.4 Determination of coefficients of the use on power of secondary обмоток of transformer of ТV1 of the guided rectifiers.

The coefficient of the use on power of secondary обмоток of transformer of ТV1 in the chart of the guided rectifier is determined in a kind

K2 = Pн / S2;

Pн = IнUн; S2 = 3UaIa, (7.3)

where Pн is an active-power in the chain of loading of rectifier;

S2 is overall power of secondary обмоток of transformer of ТV1.

7.2.5 To the point 6.2.5. Research of regulation descriptions.

Regulation description is dependence of output tension of Uн on the corner ( of adjusting :

Uн /Uн Nome = φ (α), (7.4)

where Uн of nomas is tension in the chain of loading at α = 0.

At the removal of descriptions the nominal current of Iн of nomas of loading at ( = 0 is set by a teacher. For the removal of regulation descriptions it is necessary to execute following:

• by means of switch of choice of research (see a fig. 3.1) chart to choose a necessary chart (at inductive character of loading regulation descriptions are taken off for two variants - with the additional diode of VD1 and without him);

• одключить loading of Rн, transferring the switch of SW1 in the reserved conducting state;

• to set an adjusting corner α equal 0 (extreme left position of movable indicator of control СУ unit);

• to begin a design, pushing the button "Start";

• changing resistance of Rн of loading, to set the basic value of current of Iн of loading (Iн = Iн Nome);

• changing an adjusting corner, for example with a step 20º, to take off регу-лировочную description. To bring a result in a table. 7.2 (k);

• in one system of co-ordinates to draw regulation descriptions for active and inductive character of loading;

• to define the maximal corner α of the max adjusting for every type of loading;

• to expect and fill calculation part of table 7.2 (k) Uн / Uн max, using these experimental tables. 7.2 (k), and U0, U0/U0 max:

for a monophase chart (k = 1)

;

;

for a three-phase (k = 3)

,

Table 7.2 (k) are Results of researches

, , hail	0	20	40	60	80	100	120	140
Experimental part
Uн
Calculation part
Uн / Uн max
U0
U0 / U0 max

7.2.6 To the point 6.2.6. Research of processes of functioning of the guided rectifiers.

For research of processes of functioning of the guided charts of straightening it is necessary to choose (см. рис. 3.1) the required chart (monophase, three-phase with active or inductive character of loading).

Research of pulsations is in the output chains of block of straightening of БВ and loading of the guided rectifier

For measuring of parameters of variables of constituents on the output of block of straightening of БВ of frequency of f_вu and scope U_в~of tension of u₀(t) and scope I_в~ of current of i₀(t) it is necessary to connect an oscillograph to the control points: in first case to “P₀, U” is tension of u₀(t) on the output of block of straightening of БВ (see a table. 3.3), and in the second - to “P₀, I” (current of i₀(t) on the output of block of straightening of БВ - see a table. 3.3).

For measuring of parameters of variables of constituents in the chain of loading of rectifier of frequency of f_нu and scope U_н~of tension of u_н(t) and scope I_н~ of current i_н(t) it is necessary to connect an oscillograph to the control points: in first case - to “R_н, U” is tension of the u_н(t) loading of R_н of rectifier (see a table. 3.3), and in second case of “R_н, I” is a current of i_н(t) in the chain of loading of R_н of rectifier.

The experimental values of frequencies of f_вu and f_нu of the investigated processes are determined on oscillograms accordingly u0(t) and uн(t). For this purpose it is necessary to measure duration of period of Т of the looked after curve on the mask of oscillograph, using the values of size of n multiplier "Time/Division" of the same name switch of oscillograph. The measureable temporal interval of Т is determined by work of two sizes of Т = n : lengths of measureable time domain on the screen for horizontals in divisions and values of size of n time on a division in this position of switch "Time/Division". In this case

.

At measuring of parameters of variables making (f_вu, U_в~, I_в~, f_нu, U_н~, I_н~) an oscillograph used in the mode of the closed entrance (a switch of permanent constituent of ПС is a power-off is a fig. В. 13) of strengthener of the vertical strengthening.

The methods of research of filter properties of the smoothed filters suppose implementation of next steps (to bring the results of measuring in a table. 7.3(k)) :

• by means of switch of choice of research (см. рис. 3.1) chart to choose the variant of chart of rectifier - "Single-phase with R - loading" (k = 1), " Single-phase with L -нагрузкой " (k = 2), "Three-phase with R - loading" (k = 3), "Three-phase with L - loading" (k = 4);

• to edit the parameters of source of G1 (phase tension of UА = UВ = UС = UG1 is Nome, working frequency of fc = fc nomas);

• to edit the parameters of transformer of ТV1 : to set the necessary coefficient of transformation of n12 = n12 nomas and pure resistance of r2 = r2 nomas of secondary winding of transformer of ТV1 of phase of a (ra), phases of b (rb), phases with(ra = rb = rс = r2 Nome);

• to edit the parameters of throttle of L1 : to set the basic value of inductance of throttle of L1 = L1nom;

• to edit the parameters of chart of management СУ : to set the basic value of adjusting ( = _ном) angle ; for monophase charts to make sure, that the output signals of management of phase (for monophase charts) and phases а, b, с (for three-phase charts);

• to begin a design, pushing the button "Start" (см. рис. 3.1);

• to set resistance of Rн = Rном in the chain of loading of rectifier, using the movable indicator of "Rн" (см. рис. 3.1), a providing value of current of Iн = Iн is Nome;

• to take statements of voltmeter of PV2 and ammeter of PА2. To bring the results of measuring of Uн and Iн of nomas in a table. 7.3 (k);

• to measure the scope U_в~ and frequency of fвu pulsation of tension on the output of block of straightening of БВ on the oscillogram of tension of u0(control point of Р0, U in accordance with a table. 3.3);

• to measure the scope I_в~ of pulsation of current on the output of block of straightening of БВ on the oscillogram of i0(Р0, I);

• to measure the scope U_н~and frequency of fнu pulsation of tension in the chain of loading of rectifier on the oscillogram of tension of uн(control point of Rн, U in accordance with a table. 3.3);

• to measure the scope I_н~of pulsation of current in the chain of loading of rectifier on the oscillogram of iн(Rн, I is a table. 3.3);

• to execute the analogical measuring at the currents of Iн of loading, 0,75Iн nomas, 0,5Iн nomas and 0,25Iн nomas, using the movable indicator of "Rн" - см. рис. 3.5 (to bring the results of researches in a table. 7.3 (k));

• to execute (only for the three-phase charts of k = 3 and k = 4) the analogical measuring at Iн of nomas in default of one of signals of management of uy(ωt) on the output of control СУ unit;

• researches on this methods to execute for four variants of k charts of rectifiers (k = 1, 2, 3, 4);

• for the variants of k = 2 and k = 4 to execute the analogical measuring at the different values of inductance of throttle of L1 with the additional diode of VD1 and without him - to bring the results of researches in a table. 7.4(k).

Drawing on the results of experiment (table. 7.3(k), 7.4(k)), to expect and fill calculation part of tables 7.3(k), 7.4(k) taking into account next correlations.

The results of experiment allow to define the rationed frequencies

Coefficients of pulsations on the output of block of straightening of БВ (current of Kпв and tensions of KпвU) in the chain of loading (current of Kпн and tensions of KпнU ) of rectifier :

The coefficients of smoothing out on the current of Si and tension of SU are determined taking into account the coefficients of pulsation :

Results of calculations , K_пв, K_пн, K_пвU, K_пнU, S_i, S_U to reflect in calculation part of tables 7.3(k) and 7.4(k).

On results researches to build working descriptions of Kпв, Kпн, KпвU, KпнU, Si, SU = f (Iн, С1, L1).

Research of electric processes of the guided rectifier

By means of oscillograph of model to look after the oscillograms of напря-жений and currents in accordance with the accepted denotations (see a table. 3.3) :

• tension of ua(t) of secondary puttee of transformer of ТV1 of phase and;

• current of ia(t) of secondary puttee of transformer of ТV1 of phase and;

• tension of u0(t) and current of i0(t) on the output of block of straightening of БВ (control point of Р0);

• tension of uн(t) on resistance of Rн of loading;

• tension of uya(t) on the output of control СУ of phase unit and and т. of д. (in accordance with a table. 3.3).

Table 7.3(k) are Results of researches

№

Experimental part

Calculation data

Iн And

Uн B

fвu Hertzs

∆Uв~ In

Iв~ And

fнu Hertzs

Uн~ In

Iн~ And

Kпв

KпвU

Kпн

KпнU

Si

SU

1 2 …

Diagrams need to be represented in one scale on a horizontal.

7.3 To the point 6.3. Research of out of control rectifiers (guided rectifiers at α = 0) - monophase at active(k = 1) and inductive(with the additional diode of VD1 and without him) character of loading and three-phase at active (k = 3) and inductive(with the additional diode of VD1 and without him) character of loading.

Table 7.4(k) are Results of researches

№ п/п

Experimental part

Calculation data

L1 мГн

Iн A

Uн B

fвu Hertzs

Uв~ In

∆Iв~ And

fнu Hertzs

∆Uн~ In

∆Iн~ And

Kпв

KпвU

Kпн

KпнU

Si

SU

1 2 …

Providing of the required chart of research, variant of k (k = 1, 2, 3,4) rectifier carried out by means of switch of choice of research (fig. 3.1) chart.

For providing of the required parameters of elements of chart and modes of operations of the investigated rectifier the buttons of fast access of “G1”, “ТV1”, “СУ”, “L1”, “SW1”, “SW2”, “R_н” (fig. 3.1).

Electric processes in elements and chains of однотактных charts out of control and guided at α = 0 rectifiers are identical. Therefore for research of out of control rectifiers - and monophase однотактного, and three-phase однотактного in the investigated charts (k = 1, 2, 3, 4) - it is necessary to set an adjusting α = corner 0. For this purpose it is possible to use the movable indicator of "СУ" : to bring the cursor of mouse to the movable indicator, to push the left button and, not releasing her, to move in the extreme left position.

7.3.1 To the point 6.3.1. Research of external (loading) descriptions of out of control rectifiers.

Research of external descriptions of out of control rectifiers is produced in accordance with п. 7.2.1 at the same parameters of elements charts which the of the same name guided rectifiers were investigated at.

7.3.2 To the point 6.3.2. Determination of output resistances of out of control rectifiers.

Output resistances of out of control rectifiers are determined on the basis of the got results of table 7.1(k) on correlations (7.1).

7.3.3 To the point 6.3.3 Determination of the percent lowering of output tensions of rectifiers.

Percent lowering U_н% of output tension of rectifier in transition from idling with tension of U_{н хх} to the nominal loading with output tension of U_{н ном} of nomas determined in accordance with correlation (7.2).

7.3.4 To the point 6.3.4. Determination of coefficients of the use on power of secondary обмоток of transformer of ТV1 of out of control rectifiers.

The coefficient of the use on power of secondary обмоток of transformer of ТV1 in the chart of the investigated out of control rectifier is determined in accordance with correlation (7.3).

7.3.5 To the point 6.3.5. Research of processes of functioning of out of control rectifiers.

Research of processes of functioning of out of control rectifiers is produced in accordance with a point 7.2.6 at the same parameters of elements charts which the of the same name charts of the guided rectifiers were investigated at.

7.4 To the point 6.4. Conclusions on results researches of charts of straightening.

Using data of experiments of 6.2 and 6.3, to expect, build and execute an analysis:

• regulation descriptions of the investigated charts of the guided rectifiers;

• external descriptions of the investigated charts of the guided and out of control rectifiers;

On the got results of research of the guided and out of control charts of straightening it is necessary to formulate conclusions. In these conclusions it is necessary to reflect the features of processes of functioning of every chart, results of the compared analysis of charts of straightening on basic indexes, got experimentally.