NTC-01.01.1 “Electrical engineering and basic electronics”

The laboratory stand is designed for studying electrical engineering and basic electronics in universities and secondary technical educational institutions.

The stand consists of two parts:

• body with electrical equipment, electronic boards, front panel, power pack and table top;
• machine unit (spark), containing two electrical machines: asynchronous electrical motor with squirrel-caged rotor and direct current motor with separate excitation. Optical speed sensor is installed on machine unit.

The stand body contains:

• power unit +24 V 0,5 А, +5 V 0,5 А;
• resistive bridge board with additional controllable voltage source;
• stopwatch board with resolution 0,1 sec;
• transistor time relay board with time setting RC circuit;
• transistor amplifier board;
• motor rotational speed meter board with resolution 1 rpm;
• thyristor controllable rectifier and pulse-duration converter board;
• autotransformer 0,16 kW;
• measuring complex.

Controllers are:

• switches for laboratory autotransformer, which provides the possibility to adjust voltage 0…26 V with step 2V;
• switches for alternating resistor block, which provides the possibility to adjust resistance 0…10 kOhm with step 10 Ohm;
• tumbler switch for capacitors set, which provides the possibility to adjust capacity 0…63 μF with step 1 μF;
• driving potentiometer for one phase bridge thyristor controllabe rectifier;
• driving potentiometer for pulse-duration converter;
• driving switch for additional voltage source, which provides the possibility to adjust EMF 0…10 V with step 1 V;
• driving potentiometer for time relay;
• incremental encoder for measuring complex control (displayed signals profile choosing, start of recording of measured values to memory).

The power pack contains:

• reisitors PEV-100, providing loads in laboratory works studying three phase and one phase alternating current circuits;
• transformers OSM1-0,1, inductors, throttles;
• capacitors MBGO, performed as a capacitors set;
• power transformer OSM1-0,25.

Measurements are carried out with usage of digital measuring complex integrated into the stand and connected with a PC using USB-bus. There are ten digital measuring devices with grade of accuracy at least 1, among them:

• voltmeter 3 pcs.;
• ampermeter 6 pcs.;
• wattmeter 1 pc.

It’s possible to change digital devices indication profiles during laboratory work. The following parameters are set in indication profile:

• device limit of measurement;
• measured value characteristic (current type for ampermeters and voltmeters, components of power for wattmeters).

Software and methodical documentation supplemented to the stand:

• student testing program for laboratory work authorization. It tests both theoretical knowledge and knowledge regarding the laboratory work contents. As a result student gets mark;
• measuring complex software;
• methodical and technical documentation set intended for academic staff.

The use  software allows:

• to output up to 21 measuring channels on the same coordinate axes with individual vertical tuning of scale parameters for each of them and with common horizontal tuning of scale parameters for all channels;
• to make Lissajous curves for any two measuring channels;
• to carry out any channel spectrum analysis;
• to carry out any channel signal frequency measurement;
• to calculate active, reactive components of power, total power, power factor;
• to save data massive from buffer for further analysis;
• to export oscillograms to graphic formats;
• to set DAC parameters. DAC allows to form sinusoidal, triangular and rectangular signals.

1. The study of operation modes and calculation methods of direct current linear circuits with one power supply source. Subject of inquiry: resistive bridge. In practice the experimental verification of Ohm’s and Kirchhoff’s laws and the equivalent generator concept is carried out. 
2. The study of operation modes and calculation methods of direct current linear circuits with two power supply sources. Subject of inquiry: resistive bridge with the controllable voltage source 0..10V plugged into one leg. In practice the experimental verification of Ohm’s and Kirchhoff’s laws and loop current method is carried out.
3. The study of operation modes and calculation methods of direct current non-linear circuits. Subject of inquiry: stabistor, parametric voltage stabilizer. The external loading chacteristics of stabilizer and current-voltage characteristics of stabistor are determined in this laboratory work.
4. The determination of parameters and study of operation modes of alternating current electrical circuit with series connection of inductor, resistor and capacitor. Subject of inquiry: electrical circuit containing series connected inductor (Imax=0,8 А, Lnom=0,25 H), capacitors set (1…63 μF) and active resistance (PEV-50 Rnom=47 Ohm). Chacteristics of inductor substitution circuit are determined in this laboratory work, resonance phenomena are investigated.
5. The study of alternating current power line model under changing load power factor. Subject of inquiry: power line model with active inductive load. In this work calculation of compensating capacitor and the experiment with reactive power compensation are carried out.
6. Determination of parameters and study of three-phase circuit in wye operation mode. Subject of inquiry: three-phase alternating current circuit with wye connection. In this work symmetric (with active load 11 Ohm resistance and 200 W power in all phases), uniform (with active, active inductive and active capacitive load with total resistance 250 Ohm in different phases) and non-uniform load (created from uniform when active load resistance is being reduced by changing capacitive load 1…63 μF) with or without zero wire.
7. Determination of parameters and study of three-phase circuit in delta operating mode. Subject of inquiry: three-phase alternating current circuit with delta connection. The same loads as in laboratory work 6 are investigated.
8. The study of non-sinusoidal periodic current linear circuits containing inductor and capacitor. Subject of inquiry: circuit with bridge thyristor controllable rectifier as a power source. Harmonic analysis of current and voltage in circuit with controllable active inductive loaded rectifier is carried out in this work.
9. Determination of inductor substitution circuit parameters with closed magnetic flux and air gap. Subject of inquiry: inductor with closed magnetic flux and gap. Inductor substitution circuit parameters, current-voltage characteristics are determined in this work.
10. Determination of parameters and main characteristics of one-phase transformer. Subject of inquiry: one-ohase transformer OSM-0,1 220/110 V. In this work parameters of transformer substitution circuit are determined, different operation modes are investigated.
11. The study of asynchronous three-phase motor with squirrel-cage rotor. Subject of inquiry: asynchronous motor with squirrel-cage rotor AIR56A4UZ (Pnom=120 W, nnom=1350 rpm). Mechanical and electromechanical characteristics of motor are determined. As a mechanical load a direct current motor with separate excitation in a dynamic braking mode is used.
12. Determination of parameters and main characteristics of direct current motor with separate excitation. Subject of inquiry: direct current motor with separate excitation ser. PL062UHL4 (Pnom=90 W, nnom=1500 rpm). Mechanical and electromechanical (natural and artificial – rheostatic) characteristics of motor are determined. As a mechanical load an asynchronous motor in a dynamic braking mode is used.
13. Determination of parameters and main characteristics of direct current generator with separate excitation. Subject of inquiry: direct current motor with separate excitation ser. PL062UHL4 (Pnom=90 W, nnom=1500 rpm) used as a direct current generator with separate excitation. External load and adjustment characteristics of generator are determined in this work. Generator excitation current is adjusted with usage of controllable rectifier, load is created by a pulse-duration converter. 
14. The study of capacitor charging process from constant voltage source at resistor limited current. Subject of inquiry: capacitor charge process from constant voltage source at resistor limited current. It’s possible to adjust the current-limiting resistor value. 
15. The study of a three-phase squirrel-cage induction motor control circuit. Subject of inquiry: asynchronous motor typical start circuit with different stator winding connection types (wye, delta, switching from wye to delta)
16. One stage transistor amplifier. Subject of inquiry: one stage transistor amplifier. In this work influence of transistor operating point’s shift on output signal form is investigated, gain factors with and without bypassing condenser in emitter circuit are determined.
17. The study of two stage amplifiers with direct connection. Subject of inquiry: two stage amplifier with direct connection. Common emitter and collector amplifiers input/output inner resistance ratio estimation is carried out. 
18. The study of parameters of transistor time relay with time setting RC circuit. Subject of inquiry: transistor time relay with time setting RC circuit. Time relay time characteristics are determined in this work, time delay ratio error is estimated.
19. The study of sinusoidal vibrations generator. Subject of inquiry: sinusoidal vibrations generator with phase shifting RC-circuit. Vibration excitation conditions, influence of transistor shift on generator operation steadiness and on output signal form are investigated. 
20. The study of pulse width converter (PWM) operation. Subject of inquiry: pulse width converter. Dependence of output voltage on driving voltage is determined in this work.
21. The study of Schmitt trigger operation and integral digital counters. Subject of inquiry: Schmitt trigger and binary 4-bit counter. Hysteresis with Schmitt trigger switching is investigated, binary counter state table is created.

• training laboratory equipment;
• software;
• machine unit;
• passport;
• set of jumpers.