NONCOMMERCIAL JOINT STOCK COMPANY

ALMATY UNIVERSITY OF POWER ENGINEERING AND TELECOMMUNICATIONS

Department of “Electric drive and automation”

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);

- module thyristor 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 actual the 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 independent excitation

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: U_я=const, i_B=const and R_дя=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;

- apply for a work permit 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 I_С=I_Н.

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

Table 1

n, rpm	1516	1495	1415	1350	1250
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 U_Я = const, i_B=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 permit the 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 I_C=I_N;

Experience data should be written in Table 2.

Table 2 Results of the experiment

Rдя=20 Ω
n, rpm	1516	1470	1360	1265	1102
Iя, А	0.35	0.4	0.53	0.64	0.94

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