According to their purpose, secondary connection diagrams can be: a basic, b complete, and c installation.
Having studied the symbols and prepared the necessary documentation, it is not difficult to understand the operation of any electrical installation.
Having studied the symbols and prepared the necessary documentation, it is not difficult to understand the operation of any electrical installation. How to Read Electrical Diagrams
GENERAL INFORMATION In addition to the main electrical installations, or primary connection diagrams, indicating the path of the circuit from the power source to the consumer, there are also secondary connection diagrams, in which, using conventional graphic images, elements of secondary devices are indicated, as well as connections between them and elements of the main equipment instrument transformers, switching equipment, etc.
First, let's look at the diode.
Let's pay attention to its schematic designation. For example, electrical machines may be depicted in a simplified or expanded manner. It is no secret that in a circuit any radio component, for example a microcircuit, can be connected by a huge number of conductors to other elements of the circuit.
There is no tension. During the installation and commissioning process, extensive circuits with secondary circuits have become widespread.
26. Working documentation for secondary circuits of electrical installations
SECONDARY CONNECTION DIAGRAMS
When the circuits are arranged horizontally in the diagram, the circuit designations are placed above the sections of the conductors. Straight lines are wires or tracks on a printed circuit board that connect circuit elements and along which electric current will flow.
The relay part looks somewhat more complicated, but if we look at it in parts and move sequentially, step by step, it is not difficult to understand the logic of its operation.
You may have already noticed that these resistors have a special position designation R4.
There are also numbers next to the letter designations.
Such a check is easily carried out using individual fuses for each connection or for a system of secondary connections of a complex device of protective devices [55] or, better yet, automatic circuit breakers with auxiliary contacts for signaling their operation. In alarm systems, along with light bulbs, acoustic devices are used - electric sirens, electric bells, electric horns and other similar devices.
In this regard, the question very often arises of how to learn to read electrical diagrams, where all components are displayed in the form of conventional graphic symbols. The base of the moving part is indicated as an unshaded dot; switches - their base corresponds to a dot, and for automatic switches the category of the release is drawn.
It is allowed to omit the letter index before the digital designation in cases where phase indication is not required, for example, a control circuit on alternating operating current. How to read a valve circuit diagram
About voltage circuits
Voltage circuits that come from voltage transformers are used to power:
- Measuring devices that indicate and record data - voltmeters, frequency meters, wattmeters.
- Energy meters, oscilloscopes, telemetering devices.
- Relay protective systems – remote, directional and others.
- Automated devices, emergency automation, power flows, blocking devices.
- Organs that control the presence of tension.
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They are also used to power rectifiers, which act as sources of direct operating current.
Learning to read electrical circuit diagrams
Electromagnetic relay coil.
Each group serves to designate the circuits of one CT. Conventional positional designations of elements and devices in electrical circuits of secondary connections are given in Appendices P1-P.
Their list includes primary and secondary circuits, alarm systems, protection, control and others. The 2-KM contactor is attracted and, through its contacts, supplies power to the 2-W electric motor through a thermal relay. Both single-letter and multi-letter codes are used to designate radioelements.
There are closed current paths that cover several branches at once and are called electrical circuit circuits. Their terminals can only be connected in a circuit.
Having studied the symbols and prepared the necessary documentation, it is not difficult to understand the operation of any electrical installation. Single-letter groups of radioelements A are various devices, for example, amplifiers B are converters of non-electrical quantities into electrical ones and vice versa. Conventional positional designations of elements and devices in electrical circuits of secondary connections are given in Appendices P1-P. The principles of reading circuit diagrams are important for those involved in electrical installation, repairing household appliances, and connecting electrical devices.
What is an electrical circuit
They are used in switching devices and contact connections, mainly in switches, contactors and relays. In this place there may be an intersection of tracks or a junction of wires. Even a regular iron consists of a heating element, temperature regulator, pilot light, fuse, wire and plug.
This is how they are indicated on the circuit diagram. Let's take a closer look at it.
The relay coil itself and its contacts do not have an electrical connection, but they are mechanically connected. The wiring diagrams show not only how, but also by what means the electrical connections will actually be made, the cross-section and type of control cables, clamp assemblies, and test blocks. Primary PChK-3 and secondary EVChS-24 hours, customization
PREFACE
Electrical installation work occupies an important place in the construction, commissioning and development of new capacities in the national economy. Installation of equipment and wires of secondary circuits is a labor-intensive process that requires electricians: the ability to quickly and correctly “read” secondary circuits; knowledge of the principle of operation and design of the instruments and apparatus used in them; knowledge and ability to use a wide range of materials, installation products, tools and devices; ability to properly organize and perform installation technology. Secondary electrical connection circuits include circuits and devices intended for control, signaling and blocking of switching equipment; measurements of electrical parameters in primary circuits; protection, automation and regulatory operating modes. Secondary circuits are divided according to their purpose into current and voltage, connected through measuring current and voltage transformers that convert the primary current and voltage to standard values (for example, up to 5A and 100 V), and operational with constant, rectified or alternating voltage, using operational current for influencing the on/off coils of oil switches (MB), circuit breakers, magnetic starters, to provide sound and light signals and to issue control commands from control or protection keys. Issues of installation and testing of devices of secondary circuits of electrical installations are reflected in this work on the basis of current technical standards and rules, taking into account the experience accumulated in electrical installation organizations. The peculiarity of the book is that it summarizes scattered materials and supplements them with new information necessary in electrical installation production on the transportation of cables, connecting circuits in semiconductor and telephone technology.
Replacement
The coil can only be replaced with a similar one in cases where there are no plans to improve the ignition system. Be sure to pre-clean each contact and connection in it, check to see if there are any traces of corrosion on it, and check how reliable the connections are. The thing is that corrosion processes lead to an increase in resistance in the electrical conductor, instability of the connection, and breakage. All this significantly reduces the service life of the coil. To reduce the likelihood of breakdowns in conditions of high humidity, use dielectric spark plug grease on the coil contacts.
When a problem appears in the engine, the coil serves under the most severe conditions. The malfunction provokes high secondary resistance. So, the spark plugs may wear out or there may be too large a gap between the electrodes.
If the mileage is long enough, then simultaneously with the new coil, new spark plugs are installed.
Danger
If you don't apply what you've learned and leave the coil malfunctioning, it will one day damage the entire PCM. The thing is that a lower resistance of the primary circuit leads to an increase in current in the coil. Therefore, the chances that the PCM unit will break increase.
The secondary voltage may also decrease and spark formation may weaken, starting the engine will be accompanied by many difficulties, and misfires will occur again and again.
The increased resistance of the secondary winding provokes a weakening of sparks in the cylinders and strong self-induction in the primary circuit.
Principle of operation
The coil has 2 windings wound on a metal core. The primary with hundreds of turns and 2 external contacts of the coil are connected to each other. Its positive terminal is connected to the battery, and the negative terminal is connected to the ignition module and body ground.
The secondary circuit contains thousands of turns; it is connected with the positive pole to the primary, and the negative pole to the terminal in the center of the coil.
The number of turns in other circuits fits into the proportion of 80:1. As the proportion increases, the output coil voltage also increases. The highest power coils have the largest proportion of turns.
When the primary winding is shorted to ground, an electric current is released. So, through the emerging magnetic field, the coil is charged.
Next, the ignition modules open the primary circuit. Then the field suddenly disappears. A lot of energy remains in the coil and it transmits current to the secondary circuit. The voltage can increase by more than a hundred times. At this moment a spark “runs through”.
Warning
Under no circumstances should you disconnect the high-voltage wires from the spark plugs or coils to check for sparks. The risk of injury from electric current is extremely high. In addition, there is a chance that the secondary voltage will severely damage the device. Therefore, if the need arises, spark plug testers, as well as a probe, are used in this procedure.
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If there is a problem in the coil, then measure the resistance in both windings using an ohmmeter. When deviations from normal values are detected, the coil is replaced. It is also checked using an ohmmeter with 10 MΩ of input resistance.
To test it, connect the measurement wires to the contacts in the primary circuit. Most often, the resistance ranges from 0.4 to 2 ohms. If a zero level is detected, then this is a sure sign that a short circuit has occurred in the coil. If the resistance is high, the circuit is broken.
Secondary resistance is measured between the positive terminals and the high voltage terminals. Modern devices most often have a resistance of 6000-8000 Ohms, but sometimes 15000 Ohms are also found.
In another type of coil, the primary contact may be located in the connectors or hidden.
Malfunctions
Ignition coils are reliable, durable devices. But sometimes they also malfunction. Thus, among the reasons for the appearance of defects are overheating and vibration. This leads to damage to the windings, loss of insulation, resulting in a short circuit and interruption of the circuit. The biggest danger for them is overloads, which are caused by damage to spark plugs or high-voltage wires.
When spark plugs become damaged, they develop too high a resistance. The voltage in the coil can increase until breakdowns occur in the insulation.
The insulation can be damaged due to the voltage reaching 35,000 V. When this value is reached, the voltage decreases, a misfire occurs under load, and the coil will not provide enough voltage to run the engine.
When a battery is connected to its positive contact, and a short to ground does not create a spark, this is a sure sign that the coil has completely failed and must now be replaced.
About the term
Technical literature often expresses the concept of “secondary power transmission circuits” differently. So, it also has synonyms. Often the same phenomenon is called secondary switching circuits. However, many experts consider such a replacement unsuccessful. The thing is that the secondary commutation circuit rather refers to the processes of switching electrical circuits, because the term “switching” is the name of an action.
It is important to distinguish between a number of other concepts. Electrical energy is transmitted through primary circuits. Secondary circuits are most often used with auxiliary power supplies. Their voltage is 220 V or 110 V, and the use of combined power supplies is often noted.
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The concept of “secondary power transmission circuits” can include several of their varieties:
- with direct current;
- with alternating current;
- in current transformers;
- in voltage transformers.
It also includes several tires with different purposes. To distinguish secondary power transmission circuits from their different sections, a number of special designations are used.
They are numbered taking into account the polarity of the circuits. Thus, areas of secondary power transmission circuits with positive polarity are designated by odd numbers. If the polarity is negative, even ones are used.
If we are talking about a secondary electrical circuit with alternating current, then they are designated by numbers in order, without dividing by parity. Sometimes, along with numerical designations, letters are also used.
