MEASUREMENTS AND TESTS DETERMINING THE CONDITION OF LIVE PARTS AND CONTACT CONNECTIONS OF ELECTRICAL EQUIPMENT
In addition to visual inspection, the condition of live parts and their contact connections is checked by measuring the direct current resistance of windings, individual contacts, and current-carrying sections at the points of their connections (busbars and busbars). In the presence of short-circuited turns, the measured DC resistance is, as a rule, less, and in the event of a break, unsatisfactory connection or broken contact connections, it exceeds the rated values or standardized values. The deviation of one of the measurements from the factory data is a sign that the defect is in the connection of the winding to the switch or in the soldering of the windings.
If the contacts of the switches are poorly adjusted, the DC transient resistance of the power contacts increases significantly compared to the standard values and the difference in resistance between phases increases significantly.
The condition of the grounding wires and the quality of their contact connections are determined by external inspection and based on the results of special measurements performed using grounding meters. The range of resistances that have to be measured is very large - from 10+5 (transition resistance of contacts) to 105 Ohms (resistance of relay windings, resistors). Consequently, the methods and instrumentation required to perform this work are varied.
The results of DC resistance measurements are not the only criterion for the condition of live parts. The quality of critical contact connections can be checked by special tests.
Checking connection diagrams includes primary (power) and secondary circuits (both internal and external) and requires special attention and a strict sequence of operations with a symbolic marking of the tested areas in the electrical installation circuit diagram. This test consists of an external inspection, continuity testing of circuits, determination of the polarities of winding terminals, measurement of insulation resistance and its testing, and monitoring of the operation of the circuit from a temporary voltage source.
During an external inspection, they check the compliance of the installation with the design, the condition of the contact connections, compliance with the distances between current-carrying parts and between current-carrying and grounded parts, marking and coloring of busbars, cables and their cores, wires, devices and equipment, observance of the necessary phase rotation, correct technological installation, etc. d.
Further verification is carried out by dialing, which is performed using various auxiliary devices. The most widely used elementary device is a probe consisting of a 3336 battery, a 3.5 V flashlight bulb, flexible copper insulated conductors and Crocodile clips (Fig. 23).
Fig 23 Probe circuit
Special devices (probes) UP-71 and PU-82 are produced, the semiconductor circuits of which allow you to test (ring) circuits having a resistance of up to 10 Ohms and 10 kOhms. These probes signal the presence of voltage on the circuit elements that are touched by the probes of the devices. In addition, the PU-82 device has a built-in light to illuminate the place where the probe is directed. Both devices are powered by 332 type cells.
To check external connections (power and control cables), telephone handsets, telephone headsets, intercoms (PU-82), portable radios (for example, “Cactus”) are used, with the help of which two people maintain constant communication with each other; The cable cores are wired with the devices and devices indicated above. Dialing with the help of telephone handsets of cable cores, the ends of which are located in different rooms, is shown in Fig. 24. The cable cores are disconnected from the terminal clamps. One wire from the handset is connected to “Ground” (the metal sheath of the cable), and with the other wire they “probe” all the cable cores one by one until they hear a signal in the handset, check the markings of the cable cores through which communication is established, and proceed to search for the next core cable.
The need to check the polarity of the terminals may arise when monitoring the connection of: current and voltage transformers (when meters, phase meters, power relays are connected to them), 
Fig. 24 Checking the marking of cable cores by “continuity”
1-6 marking of cable cores, MT - telephone handsets, HL - 2.5 V light bulb.
GB - battery 3336
electric motors with many leads (multi-speed motors)
The polarity of the terminals of a three-phase machine (motor, generator) is determined according to the diagram shown in Fig. 25, having previously established the terminals of each of the windings by dialing. Since the windings of a three-phase machine are shifted in space by 120 el. hail, in relation to each other, then when connecting the “-)-” battery to the beginning of the first winding and the “+” galvanometer alternately to the beginnings of the second and third windings of the battery, the galvanometer needle should deviate to the left at the moment the circuit is closed. 
Fig. 25 Scheme for checking the polarity of the windings of a three-phase electric motor
The insulation resistance of a fully assembled circuit with all connected devices (relays, coils and contacts of contactors and electromagnets, clamps, wires and cables) is measured relative to the “ground” (cable sheaths, panel housings, cabinets, panels). Using a megohmmeter, the insulation resistance of control, metering, protection, and alarm circuits is checked.
After this, the insulation is tested with increased power frequency voltage. The test voltage for the secondary circuits of protection, control, signaling and measurement circuits with all connected devices (circuit breakers, magnetic starters, contactors, relays, devices, etc.) is 1 kV, the duration of its application is 1 min. The source for it can be a special apparatus for testing secondary circuits with increased voltage. In the absence of the necessary equipment, testing with increased power frequency voltage is carried out with a 2500 V megohmmeter for 1 min.
After performing the above operations, you can apply operating voltage to the circuit from a temporary source to check the interaction of all its elements, but first you need to check and configure all the devices included in this circuit.
With this article I begin to cover one of the most interesting topics - the topic of computers, they also say circuit modeling of circuits of various electronic devices.
In general, the term modeling of electronic circuits has many synonyms, including emulation of electronic circuits, simulation of electronic circuits, etc. I will stick to the term “computer modeling” or modeling circuits on a computer, it doesn’t matter.
So, let's go.
Today, there are many computer programs that are intended primarily for the development of various electronic devices, and in such programs there is one of the important functions - emulation of electrical circuits.
I will list only the most famous of them:
LTSpice and many other programs.
Today I want to introduce you to a program from National Instruments - this is a Multisim circuit emulator.
The free Multisim program with a limit of 50 elements in the circuit can be downloaded from the manufacturer’s website at https://lumen.ni.com/nicif/confirmation.xhtml, where you can also find a version for educational institutions on the website, which is more expanded than the previous one , but also has its limitations https://lumen.ni.com/nicif/us/academicevalmultisim/content.xhtml
Let's start by studying the program interface.
The main functional panels of the program are shown in the following figure.
The component panel is of particular interest. Using the component panel, you can access the component database. When you click on any of the selected circuit component icons, a window opens Component selection. In the left part of the window you can select the required component.
The entire component database is divided into sections (passive elements, diodes, transistors, microcircuits, etc.), and sections into families (for example, for diodes, these are the diodes themselves, zener diodes, LEDs, thyristors, etc.). I hope the idea is clear.
Also in the component selection window you can see the designation of the selected component, a description of its function, and select the type of housing.
Simulation of circuits in the Multisim program.
Now let's move on to practice. Let's put together a simple circuit in Multisim and make it work!
I downloaded from the Internet a multivibrator circuit with two transistors, where LEDs are used as a load.
We can use measuring instruments, for example a virtual oscilloscope, and look at the signals at various points in the circuit.
We are convinced that the circuit works, this is where I end my acquaintance with the Multisim program. If you are interested in the topic of circuit modeling, write your questions in the comments, I will answer with pleasure.
And finally, by tradition, I present to you a detailed video on modeling circuits in the Multisim program.
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Proteus Professional is a circuit modeling system based on models of electronic components adopted in PSpice. A distinctive feature of the Proteus Professional package is the ability to simulate the operation of programmable devices: microcontrollers, microprocessors, DSPs, etc. Additionally, the Proteus Professional package includes a PCB design system. Proteus Professional can simulate the operation of the following microcontrollers: 8051, ARM7, AVR, Motorola, PIC, Basic Stamp.
Electronic Lab v2.2 (Three Phase Chains) Program for calculating three-phase electrical circuits
Electronic Lab (Three phase chains) - A program for calculating three-phase electrical circuits using the symbolic method, has a convenient, intuitive interface. Calculates a three-phase electrical circuit, both with normal and emergency operating modes: when connecting the load with a star - a phase short circuit (short circuit), a line wire break; when connecting the load with a triangle, there is a break in the load phase, a break in the line wire. Electronic Lab (Three phase chains) -
CadSoft Eagle 5.6.0
Cadsoft EAGLE is an excellent all-in-one tool for the full cycle of PCB development, starting with the creation of a circuit diagram and ending with the creation of a printed circuit board and its routing. The Pro version of the program allows you to develop printed circuit boards up to 1600x1600 mm in size (16 layers) with a resolution of up to 1/10000 mm. To do this, the program implements three modules: Schematic Module, Layout Editor, Autorouter. In addition, the program has a fairly large library, which contains a large number of standard and fairly common components, for example microcontrollers, that is, now there is no need to draw an image of the desired component on the circuit diagram and create a footprint for the printed circuit board.
D-Navigator v 0.0.106 program for selecting accessories for a cell phone.
With this program you can find out the accessories that fit your phone, as well as see new products. The program updates the database automatically (Online) via the Internet, you will always be aware of the latest news! The program has a convenient Russian menu with icons, a flexible settings menu, and a definition system. Download - D-Navigator v 0.0.106 program for selecting accessories for a cell phone. D-Navigator v 0.0.106 program for selecting accessories for a cell phone. An example of selecting compatible accessories for Nokia 6230i.
Electronics Workbench Multisim is one of the world's most popular electronic circuit design programs, characterized by a combination of professional capabilities and simplicity, extensibility of functions from a simple desktop system to a networked enterprise system. This explains the widespread use of this wonderful program both for educational purposes and for the industrial production of complex electronic devices. The archive contains the Professionals version, Russian models of op-amps, transistors, microcircuits.
Electronics Workbench Multisim v8.2.12.SP1 free download.
Features of Electronics Workbench Multisim v8.2.12 Electronics Workbench Multisim v8.2.12.SP1 - electronic laboratory on your computer at your fingertips! Electronics Workbench Multisim v8.2.12 circuit modeling system is designed for modeling and analysis of electrical circuits. Electronics Workbench allows you to simulate highly complex analog, digital, and digital-to-analog circuits. The libraries available in the program include a large set of widely used electronic components.
Electronic reference book on bipolar transistors Tranzistors v 1.2
Electronic reference book on bipolar transistors with Russian letter indices (2089 pcs.) and their foreign analogues. Pin layout drawings; sorting by different parameters; saving in a file and printing the parameters of the selected device; the ability to edit and add new transistors to the directory. Each time the program is launched, a backup copy of the database file is created, which will be used if the main database file is lost or damaged. Compression (defragmentation) of a database file, the size of which may unjustifiably grow after work related to writing/deleting data.
Cadsoft EAGLE 4.11 is a program for the development of printed circuit boards and circuits.
Cadsoft EAGLE is a comprehensive tool for PCB design, from creating a circuit diagram to creating a printed circuit board and routing it. The Pro version allows you to develop printed circuit boards up to 1600x1600 mm in size (16 layers) with a resolution of up to 1/10000 mm. To do this, the program implements three modules: Schematic Module, Layout Editor, Autorouter. In addition, the EAGLE program has a fairly large library containing many standard and fairly common electronic components, such as microcontrollers, so you will not need to draw an image of the component on the circuit yourself and create a footprint for the printed circuit board.
Libraries for Splan and Sprint-Layot
Download >>>>> Library for Splan_5.0 Download >>>>> Library for Splan_4.0 and Splan_4.0_plus Download >>>>> Library for Splan_3.0 Download >>>>> Library for Sprint-Layot
sPlan 6.0.0.2 Full (rus) - drawing diagrams. Tool for drawing electronic and electrical circuits.
A simple and convenient tool for drawing electronic and electrical circuits, sPlan 6.0.02, has been updated. The program makes it easy to transfer symbols from a library of elements to a diagram and link them to a coordinate grid. sPlan has many drawing and editing tools that make diagram development convenient and efficient, such as auto-numbering of elements, compiling lists of elements, and others. sPlan contains so many convenient and varied functions that their use is limited only by your desires and needs, you can create a wide variety of drawings and diagrams!
Navigate discs at the speed of thought. Explorer Lista
Sometimes you can look at ordinary and familiar things from a different angle and get completely unexpected results. Windows Explorer is already in its second decade. It would seem that there could be something new in it? It turns out that in a couple of minutes you can make Explorer much more convenient and faster. The object of our attention today will be the Explorer Lista program, developed for Windows XP/2000/2003. You can download it here. After installation and launch, a navigation bar appears in Explorer.
Electronic circuit simulator in Russian is an ordinary SPICE simulator called TINA-TI with an easy-to-understand graphical shell. This program works without any limit on the number of devices used and easily handles comprehensive work. Perfectly suited for simulating the behavioral response of a variety of analog circuits, as well as switching power supplies. Using TINA-TI, you can easily design a circuit of any degree of complexity, connect previously created fragments, examine and recognize the quality indicators of the circuit.
All presented elements available electronic circuit simulator in Russian TINA-TI, are dispersed into six types: passive components, switching switches, semiconductor devices, measuring devices, miniature models of devices of increased complexity. Additionally, this software includes many representative samples.
Electronic circuit simulator compiled in Russian, so with its help you can easily master drawing and adjusting circuit diagrams. The process of creating a circuit in itself is not complicated, and after this operation is completed, the simulation stage begins. The program can perform the following types of research: evaluation of direct and alternating current. This analysis includes calculation of key stresses, plotting the final result, determining intermediate parameters and testing temperature.
Next comes the study of intermediate processes and noise distortions. Depending on the category of research, the curriculum forms the final result in the form of graphics or tables. Before starting the simulation, TINA-TI checks the circuit for errors or errors. When any deviations are detected, all the defects will be shown in a separate window in the form of a list. If you click on an inscription with an error not recognized by the simulator, the part or part of the drawing will be indicated by markers.
Additionally, TINA-TI can measure and test various signals. To implement this type of research, there are virtual devices for this: a digital multimeter, an oscilloscope, a signal tester, a source of periodic signals and a recording device. All simulation devices available in the program correspond as closely as possible to the use of actual measuring devices. They can be virtually connected in any part of the circuit under study. All information data received by conventional devices is stored in the computer memory.
Drawing on paper is not a pleasure for everyone - it takes a long time, it is not always beautiful, it is difficult to correctly calculate the dimensions right away, and it is inconvenient to make adjustments. All these problems can be easily solved by a program for drawing diagrams. Most modern software products contain a library with a set of basic elements. From them, as from a constructor, the required configuration is assembled. Edits and corrections are made quickly, and you can save different versions.
There are quite a few programs for drawing electrical diagrams that you can use for free. Some of these are demo versions with limited functionality, some are full-fledged products. To design a wiring diagram for an apartment or house, these functions are sufficient, but for professional use a product with more extensive functionality may be required. Paid options are more suitable for these purposes.
Like any software product, a program for drawing diagrams is evaluated by ease of use. The interface should be simple, convenient, and functional. Then even a person without special computer skills can easily figure it out. But, nevertheless, the main factor is the sufficiency of functions for creating circuits of varying complexity. After all, you can adapt to even an inconvenient interface, but it’s more difficult to make up for the absence of some parts.
A simple program for drawing diagrams VISIO
Many of us are familiar with Microsoft office products and Visio is one of the products. This graphic editor has an interface familiar to Microsoft products. Extensive libraries contain all the necessary components; you can create schematic and wiring diagrams. Working in VIZIO is easy: in the library (window on the left) we find the desired section, look for the required element in it, drag it to the work field, and put it in place. The dimensions of the elements are standardized and fit together without problems.
Vision program for drawing diagrams - clear interface
What’s nice is that you can create diagrams to scale, which will make it easier to calculate the required length of wires and cables. What’s also good is that it doesn’t require much space on your computer’s hard drive; even not very powerful machines can handle this program for drawing diagrams. It’s also nice to have a large number of video lessons. So there will be no problems with mastering it.
Clear ProfiCAD
If you need a simple program for designing electrical wiring, pay attention to ProfiCAD. This product does not require downloading libraries like most others. The database contains about 700 built-in elements, which are enough to develop a power supply diagram for an apartment or private house. The available elements are also sufficient to create not too complex electrical circuit diagrams. If some element is missing, you can add it.
The main disadvantage of the program for drawing ProfiCAD diagrams is the lack of a Russian version. But even if you are not strong in English, it’s worth a try - it’s very simple. In a couple of hours you will master everything.
The principle of operation is simple: in the field on the left we find the desired element, drag it to the desired place in the diagram, and rotate it to the required position. Let's move on to the next element. After completing the work, you can receive a specification indicating the number of wires and a list of elements, and save the results in one of four formats.
Compass Electric
A program with more serious functionality is called Compass Electric. This is part of the Compass 3D software. In it you can not only draw a circuit diagram, but also block diagrams and much more. At the output you can get specifications, purchasing sheets, connection tables.
To get started, you need to download and install not only the program, but also the library with the element base. The program, explanations, help - everything is Russified. So there will be no problems with the language.
When working, select the desired section of the library, graphic images appear in a pop-up window. In it, select the necessary elements, drag them onto the working field, installing them in the right place. As the diagram is formed, data about the elements falls into the specification, where the name, type and value of all elements are recorded.
The numbering of elements can be done automatically, or manually. The method is selected in the settings menu. You can change it during operation.
QElectroTech
Another program for drawing circuits is QElectroTech. The interface resembles Microsoft products and is easy to work with. There is no need to download a library for this program; the element base is “built-in”. If something is missing there, you can add your own elements.
The finished diagram can be saved in the get format (for further work with it in the program) or as an image (jpg, png, svg, bmp formats). After saving, you can change the dimensions of the drawing, add a grid, a frame.
QElectroTech - free editor for creating electrical circuits
This program has some disadvantages. The first is that inscriptions can only be made in one font, that is, if you need a drawing in accordance with GOST, you will have to somehow figure out how to change the font. Secondly, the sizes of frames and stamps are specified in pixels, which is very inconvenient. Overall, if you need a diagramming program for home use, this is a great option. If compliance with GOST requirements is required, look for another one.
Electronic circuit simulation program 123D Circuits
If you don't know how to draw a diagram on a computer, take a closer look at this product. 123D Circuits is an online service that allows you to create a not very complex circuit with the ability to create printed circuit boards. There is also a built-in simulator that simulates the operation of a finished circuit. The function of ordering a batch of finished boards is available (for a fee).
Before you start, you need to register and create your profile. After which you can start working. Several users can work on one project using shared libraries. In the free version of the program, you can create an unlimited number of schemes, but they will be publicly available. In the amateur rate ($12), five circuits can be personal, and a 5% discount on board production is also offered. The professional plan ($25) gives you an unlimited number of personal circuits and the same discount on board orders.
The circuit can be drawn from existing components (there are not very many of them, but it is possible to add your own) or imported from the Eagle program. Unlike other programs, the 123D Circuits library does not contain schematic symbols of elements, but mini copies of them. Interface with two side fields. On the right, the library section with the element base is displayed, on the left - part of the settings and a list of used elements. After completing the work, the program itself generates a schematic diagram and also suggests the location of elements on the board (can be edited).
Everything seems to be good, but 123D Circuits has serious shortcomings. First, the results of simulated work are often very different from real readings. Secondly, the functionality is small; it will not be possible to create a truly complex circuit. Conclusion: this program is mainly suitable for students and beginner radio amateurs.
Paid programs for drawing electrical circuits
There are many paid graphic editors for creating diagrams, but not all of them are needed for “home” use or for work that is not directly related to design. Paying a lot of money for unnecessary features is not the smartest decision. In this section we will collect those products that have received a lot of good reviews.
DipTrace - for PCB development
For experienced radio amateurs or those whose work involves designing radio products, the DipTrace program will be useful. It was developed in Russia, therefore it is entirely in Russian.
It has a very useful function - it can develop a printed circuit board using a ready-made circuit, and it can be seen not only in two-dimensional, but also in a three-dimensional image with the location of all the elements. It is possible to edit the position of elements on the board, develop and adjust the device body. That is, it can be used both for designing wiring in an apartment or house, and for developing some devices.
In addition to the program for drawing diagrams, you will also need to download a library with an element base. The peculiarity is that this can be done using a special application - Schematic DT.
The interface of the program for drawing circuits and creating printed circuit boards DipTrace is convenient. The process of creating a diagram is standard - we drag the necessary elements from the library onto the field, rotate them in the required direction and install them in place. The element that is currently being worked on is highlighted, which makes the work more comfortable.
As the diagram is created, the program automatically checks the correctness and admissibility of connections, matching dimensions, compliance with gaps and distances. That is, all edits and adjustments are made immediately, at the creation stage. The created circuit can be run on the built-in simulator, but it is not the most complex, so it is possible to test the product on any external simulators. It is possible to import a diagram for use in other applications or accept (export) an already created one for further development. So DipTrase diagram drawing software is a really good choice.
If you need a printed circuit board, we find the corresponding function in the menu; if not, the diagram can be saved (it can be adjusted) and/or printed. DipTrace diagram drawing software is paid (there are different plans), but there is a free 30-day version.
SPlan
Perhaps the most popular program for drawing diagrams is SPlan. It has a well-designed interface, extensive, well-structured libraries. It is possible to add your own elements if they are not in the library. As a result, it’s easy to work with; you can master the program in a few hours (if you have experience working with similar software).
The disadvantage is that there is no official Russified version, but you can find it partially translated by craftsmen (the help is still in English). There are also portable versions (SPlan Portable) that do not require installation.
One of the “lightest” versions is SPlan Portable
After downloading and installing the program, you need to configure it. This takes a few minutes, and the settings are saved on subsequent launches. Creating diagrams is standard - find the desired element in the window to the left of the work field, drag it into place. Numbering of elements can be done automatically or manually (selected in the settings). What’s nice is that you can easily change the scale by scrolling the mouse wheel.
There is a paid (40 euros) and a free version. The free version disables saving (bad) and printing (you can get around it by taking screenshots). In general, according to numerous reviews, it is a worthwhile product that is easy to work with.
