Structurally, the stand consists of three parts:
- case in which a part of the electrical equipment, electronic boards, front panel and countertop of the integrated desktop are installed;
- a machine assembly, which includes one independent electric motor of direct current, one asynchronous electric motor with a squirrel-cage rotor, an optical speed sensor with determination of the direction of rotation, a flywheel to create an inertial moment;
- induction motor with a phase rotor.
The stand provides the supply, control and distribution of primary energy resources for various types of enterprise load. In laboratory conditions, the electric power system reproduces a decrease in the input power supply from the power transmission line through the power supply line to the internal production network. The load unit consists of an electric machine unit (DC motor-AD) with a frequency inverter and a pulse-width converter, an adjustable active inductive load, a lighting unit and a thyristor rectifier with an active inductive load. Reactive power compensation in the system is carried out by a synchronous machine and a capacitor store. The stand is equipped with a PC-based measuring and computing complex. The energy system of the enterprise reproduced by the laboratory complex is controlled and monitored using a PC with software and methodological support.
The following equipment is located inside:
- Frequency converter designed to form a three-phase AC network of adjustable frequency and voltage supply of an induction motor. The converter is based on the MB90F562 microcontroller (Fujitsu) and the PS11033 (Mitsubishi) power intelligent module. The controller serves for calculating the input (setting voltage, frequency and current of dynamic braking) and output (current, voltage) signals of the converter, organizing data exchange with a PC, and outputting measured values to the front panel of the stand.
- Power circuits of a three-phase bridge rectifier, a three-phase bridge inverter with IGBT transistors, as well as driver and protection circuits from short circuits, insufficient driver supply voltage, incorrect supply of control signals. The frequency converter allows you to explore the asynchronous electric motor in all four quadrants of the mechanical characteristic, as well as realize dynamic braking of the motor with an adjustable current.
- A pulse-width converter designed to power the armature circuit and the excitation winding of a DC motor, as well as power the rotor circuit of a three-phase asynchronous motor with a phase rotor in the synchronous motor and generator mode. A pulse-width converter is implemented on the power element base of the frequency converter. Two of its shoulders are used to obtain a reversible symmetric NIP (power supply of the DC motor anchor), and the remaining arm is used as a non-reversible NIP for the rotor of a three-phase asynchronous motor. Power supply of the excitation winding DC motor is implemented on a separate MOSFET from International Rectifier.
- The control system is based on the AT Mega163 (Atmel) microcontroller and implements calculations of the input (voltage, frequency and dynamic braking current) and output (currents of the armature, excitation, rotor) signals, the organization of data exchange with a PC, the output of measured values ??to the front panel of the stand.
The pulse-width converter of the DC armature circuit of the DC motor is supplemented by the closed-loop operation mode (current or speed regulation), as well as the generator operating mode.
- Power starters of the relay subsystem.
- Overvoltage reset resistors on smart modules.
On the lower shelves you can find:
- load resistors;
- compensating capacities;
- load inductance;
- power starters of the relay subsystem.
The training system is supplied with:
- student testing software for admission to laboratory work. In the testing process, both theoretical knowledge and knowledge of the contents of the laboratory work performed are checked. As a result of testing, the student receives an assessment of knowledge;
- measuring complex software;
- a set of methodological and technical documentation intended for the teaching staff.
The software allows to:
- control the operation of the stand with the display of all parameters on the PC screen;
- repeat the basic theoretical provisions investigated in laboratory work;
- check students’ knowledge before doing laboratory work (theoretical questions, correct assembly of the circuit, knowledge of the hardware, step-by-step control of understanding the choice of the experimental design and measuring instruments for the implementation of specific educational goals);
- perform laboratory work of various difficulty levels;
- carry out real-time mathematical calculations on measured electrical quantities and their graphical display;
- save received data.