The training system is the transformation of NTC-07.02 “Electric drive automatic control”.
The main feature of the training system is the use of built-in microprocessor measuring system (MPMS), which allows to control measured values in steady and transition modes, to improve the measurement accuracy and number of controlled parameters, to provide PC connection, to simplify and automate the measurement and calculation processes.
Structurally, the training system consists of the case with installed electrical equipment, relay unit, electrical plates, front panel and countertop of integrated desktop.
The case consists of:
- power unit +5 V (current 1 А), +15 V (current 1 А), -15 V (current 1 А), +18 V (current 0,1 А), +110 V (current 1 А), +24 V (current 2 А);
- electrical relay circuit board (3 time relays,1 current relay);
- stopwatch circuit board with resolution 0,1 sec;
- control unit circuit board, thyristor voltage regulator;
- rectifier circuit board;
- relay unit;
- measurement complex MPSO (digital oscilloscope);
The front panel has electrical schematics of investigated objects. All scheme, displayed on the panel, are divided into groups according to the theme of conducted experiments.
The panel includes: switch sockets, digital stopwatch indicator, switch instruments – DC/AC ammeters, voltmeter, speed measurement, DC motor SL-221, AC motor UAM-052, tachogenerator, switch gear apparatus, controls, providing to measure elements parameters during laboratory experiment.
Functionally, the front panel is divided on six units:
1.Control schematics of DC electric motor.
The unit allows to investigate DC motor start in time function, in reactance voltage function, in current function, braking in time function, in reactance function, plugging.
2. Control schematics of asynchronous electric motor.
The unit allows to investigate the start, reverse, plugging, dynamic braking of asynchronous motor with squirrel-cage rotor. The current regulator of dynamic braking is located inside the unit.
3. Thyristor converter and closed control system DCM unit.
Thyristor regulator provides smooth measurement of output voltage from 0 to 80 V. Closed control system has back current and speed couplings.
4. Electric machine unit with following installed equipment:
DC electric motor, asynchronous motor with squirrel-cage rotor and tachogenerator. The electric cars shafts are connected with each other by rubber belt.
5. Regulators and stopwatch unit.
Time controllers, current relay, comparator actuation level relay, current level regulator of dynamic braking, adjustable starting resistors in the armature motor circuit are located in the unit. Digital stopwatch indicator and its controllers are located in the unit.
6. Measurement equipment and power supply unit. Power switch, LED switch power indication in each phase, line fuses are located inside the unit. Digital indicators measure direct and alternating current and voltage, frequency and rotation direction with accuracy class 1.
To conduct laboratory experiment it’s necessary to collect the circuit of investigated object, using jumpers, which allow to show the circuit in visual form.
The measurements are conducted by digital measurement complex, built-in the training system and connected to PC via USB bus.
It’s possible to conduct laboratory experiments, using manual mode and dialogue mode with PC. During laboratory experiments, MPSO allows to save the received data with discreteness 0,2 sec (maximum 50 values of each measured value) to construct the graphics of transition processes with high accuracy.
Simultaneously with PC, MPSO operates in the mode of multichannel digital storage oscilloscope with the possibility to process the received data with disconnected training system.
In this case the laboratory experiments are conducted in PC dialogue mode: familiarization with the technique, knowledge control, test circuit assembly, experiments on the training system, data processing and registration on the PC.
The training system is supplied with:
- a software to test and pass students before the experiment. Both theoretical knowledge and knowledge of the contents of the laboratory experiment are checked. As a result of testing the student receives the mark;
- measurement system software;
- a set of methodical and technical documentation for teaching staff.
The use of MPMS with PC allows to:
- display in one coordinate axis up to 21 measuring channels, with individual vertical scale adjustment for each channel and a horizontal horizontal scale common to all channels;
- build Lissajous figures for any two measuring channels;
- analyze the spectrum of any of the used measuring channels;
- measure the signal frequency on any of the channels used;
- calculate the active, reactive components of power, apparent power, power factor;
- save an array of data from the buffer for subsequent analysi
- export waveforms to graphic formats;
- set the DAC parameters. DAC allows you to generate signals of sinusoidal, triangular and rectangular shapes.