Laboratory work № 6.Research of the direct current motor of parallel excitation




REPORT

On laboratory work №6

On the discipline “Electric machines”

Theme: “Research of the direct current motor of parallel excitation”

Specialty: 5B071800- Electrical Power Engineering

Done by: Shaimuradov E. Group: EPEe-15-10

Checked by: Abdullaev Z.M.

 

_________ ___________ “___” __________ 2017

(score) (signature)

 

Laboratory work № 6.Research of the direct current motor of parallel excitation

Objective of the work: view the ways of starting the motor of independent excitation, research mechanical, working and adjusting properties of the motor.

 

Program of work

 

1. Study the scheme for experimental research of DC motor of independent excitation (hereinafter, the DC motor of independent excitation), the composition and purpose of the modules used in the work.

2. Assemble the circuit for an experimental study of a DC motor of independent excitation. Carry out a test inclusion.

3. Take off the natural mechanical characteristic.

4. Take off the artificial mechanical characteristics with additions resistance in the armature circuit.

5. Take off the artificial mechanical characteristic the weakening magnetic flux.

6. Take the off workings characteristics of the DC motor of independent excitation.

7. Conduct experimental data processing, compile a report and to make a conclusion on work.

 

Explanations for work

 

In the laboratory work the following modules are used:

- Stand Power Module (SPM);

- power module (PM);

- modulethyristor converter (TC);

- power module (PM);

- module of additional resistance number 1 (MAR1);

- module of additional resistance number 2 (MAR2);

- Measuring module (MM).

 

Before conducting laboratory work, you must bring the modules to their original state: - the button "Network" of the thyristor converter module is brought to the lower position, switch SA6 - to the lower position. Thyristor converter must be switched to speed control mode (Appendix E);

- switch SA1 MDS1 set to the position "∞";

- Set the switches SA1, SA2 MDS2 to the "0" position.

 

 

The study machine DC is part of the electric machines, which includes the actualthe machine under investigation is a direct current M2, the loading machine - machine AC - M1 and pulse speed sensor M3.

The scheme for investigating the DC motor of independent excitation is shown in figure 1.

 

 

Figure 1 - Scheme for the investigation of a DC motor

of an independentexcitation

 

The anchor circuit of the DC motor through the additional resistance RP1 of the MDS2 module and the current and voltage sensors is connected to the output of the UTP of the thyristor converter.

The asynchronous motor is connected through the additional resistance (MDS1) directly to the network (MP). Control the DC motor parameters by using the thyristor converter module. The current of the stator IC is measured by means of the ammeter of the MI module.

 

1. Determining the direction of rotation of motors

 

Before carrying out experiments necessary to determine the direction of rotation of the motors:

- switch on the QF1 and QF2 automata of the MPS and MP modules, respectively;

- apply for a work permit TP (SA6) And, choosing the direction of rotation, set the potentiometer RP1 voltage 200V, remember the direction of rotation of the motor;

- switch the resistance from the stator circuit of the induction motor of a short circuit, start the motor, remember the direction of rotation. It must be opposite to the direction of rotation of the DC motor. If this is not the case, switch SA1 of module MDS1 to the position "∞", change the phase "A" and "B" on the power module and check the direction of rotation.

 

2. The natural mechanical characteristic of a DC motor of independent excitation

 

The natural mechanical characteristic of a DC motor of independent excitation it represents the dependence of the rate of load torque at a constant value of the voltage at the motor clamps and the absence of additional resistance in the anchor circuit: Uя=const, iB=const and Rдя=0.

 

The experiment is carried out in the following sequence:

- switch on the QF1 and QF2 automata of the MPS and MP modules, respectively;

- apply for f a work permit TP (SA6), and sets the direction of rotation, potentiometer RP1 set voltage 200V;

- applyforaworkpermit switch SA1 of the module MDS1 to enter resistance, the mostly, the motor is loaded until the armature current reaches 1.5A or the stator current reaches IС=IН.

The data of the experiment are listed in Table. 1.

 

Table 1

n, rpm          
Iя, А 0.37 0.41 0.54 0.64 0.91

 

After the experiment, set all the module switches to their original state.

 

3. The artificial mechanical characteristic of a DC motor of independent excitation when added the resistance into the armature circuit

 

The artificial mechanical characteristic of the independent excitation motor is the dependence of the velocity on the load moment with additional resistance in the anchor circuit: at UЯ = const, iB=const.

The experiment is carried out in the following sequence:

- switch on the QF1 and QF2 automata of the MPS and MP modules, respectively;

- switch SA1 of the module MDS2 set to a non-zero position, to make the first measurement;

- apply for a work permitthe operation of the thyristor converter (SA6) and, setting the direction of rotation, set the voltage of the potentiometer RP1 to 200V;

- to introduce resistance by the switch SA1 of the MDS1 module, thereby loading the DC motor until the armature current reaches 1.5A or the stator current reaches IC=IN;

Experience datashould be written in Table 2.

 

Table 2 Results of the experiment

Rдя=20 Ω
n, rpm          
Iя, А 0.35 0.4 0.53 0.64 0.94

 

According to table 2 to construct the characteristics of n=f(IЯ).

 

 

Figure 2

 

4. Artificial mechanical characteristic of the motor of a constant independent excitation with magnetic flux attenuation

 

Artificial mechanical characteristic of an independent engine
excitementsis the dependence of the velocity on the moment of loadingat a constant value of the voltage at the motor clamps and introduction of additional resistancein the excitation winding circuit: UH=const, iB=const.

The experiment is carried out in the following sequence:

- switch on the QF1 and QF2 automata of the MPS and MP modules, respectively;

- apply for the operation of the TP (SA6) and, setting the direction of rotation, set the voltage of the potentiometer RP1 to 200V;

- switch SA2 of the module MDS2 set to a nonzero position, make the first measurement;

- Switch SA1 of the module MDS1 to enter resistance, thethus, loading of the DC motor as long as the armature current reaches 1.5AMDS1, thereby loading the DFT until the armature current reaches 1.5A or the stator current reaches IC=IN.

The data of the experiment are listed in table. 3.

 

Table 3 Results of the experiment

RдB=220
n, rpm            
Iя, А 0.3 0.33 0.35 0.5 0.63 0.95

 

After the experiment, set all the module switches to their original state.

According to Table 3, we construct the characteristics n = f (IЯ).

 

 

Figure 3

 

 

5. Performance characteristics of DC motor of independent excitation

Workers characteristics motors are the dependence of the rotational speed,
electromagnetic moment, armature current and efficiency of useful power on the motor shaft at constant value of the voltage at motor clamps n or ω; M, Iя, ŋ=f(P2) with Uя=Uян=const, iB=const. The experience is in the following sequence: 6. Performance characteristics motor directly current independent excitation workers characteristics motors are the dependence of the rotational speed, electromagnetic moment, armature current and efficiency of useful power
on the motor shaft at constant value of the voltage at motor clamps n or ω; M, Iя, ŋ=f(P2) with Uя=Uян=const, iB=const.

The experience is in the following sequence:

- turn onautomata QF1, QF2;

- to file a permiton the work of the TP (SA6) and,settingdirection ofrotation,potentiometer RP1set the voltage UЯ=0,75·UЯН;

- switch SA1module MDS1introduce resistance,thereby loading the DС motor, until the armature current will not reach or stator current will not reach IС=IН=1,3А.
- as you increase load potentiometer RP1 of the TP module support the weekend converter voltage at the level given.
Record the experience data in Table 5.
Table 5 Results of the experiment

Experimental data Calculation data
Uя IЯ n iв Ря М М0 М2 Р2
V А rpm 1/с А W W W   Nm А Nm Нm W %
  0.3   141.7 0.22   39.69 93.69 0.15 0.045 0.183 0.027 0.018 25.51 27.2
  0.4   141.3 0.217 71.2 38.6 109.8 0.148 0.059 0.181 0.0268 0.0322 45.5 41.4
  0.5   127.5 0.195   31.18 111.18 0.135 0.067 0.175 0.0236 0.044 56.1 50.4
  0.7   121.5 0.193 110.6 30.54 141.14 0.13 0.091 0.174 0.0226 0.068 82.62 58.5

 

After the experience set all module switches into the initial state.
Calculation data.
Power, supplied to the motor armature, W

 

РЯ = UЯ·IЯ.

 

Electrical losses in the excitation circuit, W

 

 

whererВ - resistance of the excitation winding (Appendix B); iВ is the excitation current of a DC motor, A

 

 

Power supplied to the DC motor, W

Р1Я+ .

 

Electromagnetic moment, N*mМ = СМ*IЯ,

 

where CM is adopteddepending onfrom angularrotation speed (AppendixB).The moment of idlingengine,proportionalmechanical losses andlosses insteel, N*m,

 

 

М0М·IЯ0,

 

whereIЯ0 - is adopted depending on the angular frequency of rotation (Appendix B).

 

Useful moment on the shaft of the DC motor, N*m

 

М2=М-М0.

 

Useful power on the motor shaft, W

Р2=ωМ2.

 

Efficiency,%

 

 

 

Figure 4— Working characteristics

 

 

Conclusion

 

Control questions

1. How to change the direction of rotation of the DCM?

2. Why does the DCM(Direct current motor) increase the armature current with increasing load on its shaft?

3. Why, with a decrease in the excitation current, the rotational speed of the DCM is increasing?

4. How should the armature current change with decreasing excitation current and constant resistance moment on the motor shaft?

5. How will the appearance of the mechanical characteristics of the engine change if an additional resistance RДЯ is introduced into the armature circuit?

 

Listofreferences

1 Копылов И.П. Электрические машины.-М.: Высшая школа, Логос, 2000. -607 с.

2 Брускин Д.Э., Зорохович А.Е., Хвостов В.С. Электрические машины. Ч. 1,2. -М.: Высшая школа, 1987.

3 Копылов И.П. Электрические машины.-М.: Энергоатомиздат, 1986.-360 с.

4 Вольдек А.И. Электрические машины.-Л.: Энергия, 1978.-832 с.

5 Костенко М.П., Пиотровский Л.М. Электрические машины. Ч.2 Машины переменного тока.- Л.: Энергия, 1973. - 412 с.

 



Поделиться:




Поиск по сайту

©2015-2024 poisk-ru.ru
Все права принадлежать их авторам. Данный сайт не претендует на авторства, а предоставляет бесплатное использование.
Дата создания страницы: 2018-01-08 Нарушение авторских прав и Нарушение персональных данных


Поиск по сайту: