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How serious is fainting?

Causes of fainting

Let's repeat it again. Fainting is the most familiar mechanism of blackout. Fainting is the result of rapid dilation of blood vessels or weakening of the left ventricular function of the heart. Fainting can also occur in completely healthy people. They can be affected by stress, fear, mental or physical trauma, severe pain, and so on. In such cases, the human body reflexively tries to protect itself from reality, which is very difficult to experience “in reality.”

Fainting caused by pathological conditions

As you already know, any disease requires timely treatment. This also applies to fainting conditions. It is necessary and possible to fight them. Treatment of fainting involves treatment of the underlying disease, if any, and relief of the fainting condition itself. If a person is young and is bothered by vasodepressor syncope, most often he does not require special treatment. It is quite enough to relieve the patient from the fear of fainting and explain to him the very essence of the existing disease. Some patients in such cases are prescribed beta blockers such as bellataminal, ephedrine or disopyramide, which stop excessive activity of the vagus nerve, or reuptake inhibitors such as serotonin or fluoxetine, which act on the central mechanisms.

Remember, despite the fact that fainting is the most familiar mechanism of blackout and at first glance has virtually no effect negative impact on general state person in the future, it is necessary to fight with him. There is no point in letting the existing problem take its course. This will only worsen your general condition. Get treatment and let “fainting pass you by”!

Device protective shutdown(RCD) is an electrical low-voltage device that serves to automatic shutdown protected area electrical circuit in the event of a differential current exceeding the permissible value for this device. You can also come across such an abbreviation as VDT - this is a differential current switch, that is, actually the same thing. In this article, we will look at the readers about the device, purpose and operating principle of an RCD used in electrical engineering.

Purpose

First, let's look at the purpose of the residual current device (in the photo below you can see its appearance). occurs in the event of a violation of the integrity of the cable insulation of one of the electrical wiring lines or in the event of damage to structural elements in a household electrical appliance. A leak can lead to either an operating household electrical appliance, as well as electric shock during operation of a damaged electrical appliance or faulty electrical wiring.

In the event of an unwanted leakage, the RCD in a fraction of a second disconnects the damaged section of electrical wiring or a damaged electrical appliance, which protects people from electric shock and prevents the occurrence of a fire.

The question is very often asked about... The difference between the first one is that this protective device, in addition to protection against electrical leakage (RCD function), additionally has protection against and short circuit, that is, performs the functions circuit breaker. The residual current device does not have overcurrent protection, so in addition to it, circuit breakers are installed in electrical networks to implement protection.

Device and principle of operation

Let's look at the design of the residual current device and how it works. The main structural elements of the RCD are a differential transformer that measures the leakage current, a trigger element that influences the shutdown mechanism and the power contact release mechanism itself.

The operating principle of the RCD in single-phase network next. The differential transformer of a single-phase protection device has three windings, one of which is connected to the neutral conductor, the second to the phase conductor, and the third is used to fix the difference current. The first and second windings are connected in such a way that the currents in them are opposite in direction. In the normal operating mode of the electrical network, they are equal and induce magnetic fluxes in the magnetic circuit of the transformer, which are directed counter to each other. The total magnetic flux in this case is zero and, accordingly, there is no current in the third winding.

In the event of damage to an electrical appliance and the appearance of phase voltage on its body, when touching the metal body of the equipment, a person will be exposed to leakage of electricity that will flow through his body to the ground or to other conductive elements that have a different potential. In this case, the currents in the two windings of the differential transformer RCD will be different, and accordingly, magnetic fluxes of different magnitudes will be induced in the magnetic circuit. In turn, the resulting magnetic flux will be different from zero and will induce in the third a certain value of current - the so-called differential one. If it reaches the triggering threshold, the device will work. We described the main ones in a separate article.

More information about how the RCD works and what it consists of is described in the video lessons:

Do you want to know how a residual current device works in a three-phase network? The operating principle is similar to a single-phase device. The same differential transformer, but it already compares not one, but three phases and the neutral wire. That is, in a three-phase protective device (3P+N) there are five windings - three windings of phase conductors, a winding neutral conductor and a secondary winding, through which the presence of a leak is detected.

In addition to the above structural elements, a mandatory element of the residual current device is a testing mechanism, which is a resistor connected via the “TEST” button to one of the windings of the differential transformer. When you press this button, the resistor is connected to the winding, which creates a difference current and, accordingly, it appears at the output of the secondary third winding and, in fact, simulates the presence of a leak. Triggering of the residual current device indicates that it is in good condition.

Below is the symbol of the RCD in the diagram:

Application area

The residual current device is used to protect against current leakage in single-phase and three-phase electrical wiring for various purposes. In a home, an RCD must be installed to protect the most dangerous household electrical appliances from the point of view of electrical safety. Those electrical appliances, during the operation of which there is contact with metal parts of the housing either directly or through water or other objects. First of all, this is an electric oven, washing machine, water heater, dishwasher, etc.

Feature toggle- development technique software products, which provides support for connecting additional functionality to a running application. This allows you to use continuous integration, keeping the application running and hiding functionality that is under development.

The basic idea is that in the source code there is a block with additional functionality (often not fully implemented) and a conditional statement that determines whether this functionality is enabled or not.

Add, enable or disable functionality

To add, enable or disable functionality, there is a special FeaturesPage located at:

[Application URL]/0/Nui/ViewModule.aspx#BaseSchemaModuleV2/FeaturesPage

For example:

Http://mybpmonline.com/0/Nui/ViewModule.aspx#BaseSchemaModuleV2/FeaturesPage

To add a new disabled functionality, specify its code, name and short description, and then click the [Add functionality] () button (Fig. 1).

Rice. 1. - Interface for adding new functionality

To enable or disable functionality, use the appropriate attribute (Fig. 2, 1). To apply the changes, click the [Save changes] () button (Figure 2, 2).

Rice. 2. - Turn on/off functionality

Storing functionality information in a database

The list of functionality available for enabling/disabling is stored in a table Feature application database. By default the table is empty. Main table fields Feature are given in table 1.

Table 1. - Main fields of the table Feature

Information about the functionality status (enabled/disabled) is contained in the field FeatureState tables AdminUnitFeatureState(Fig.3) . Table AdminUnitFeatureState links tables Feature And SysAdminUnit which defines users and user groups of the system. Main table fields AdminUnitFeatureState are given in table 2.

Table 2. - Main table fields AdminUnitFeatureState

Rice. 3. - Table relationship diagram

Defining new functionality in program code

To implement additional functionality into the source code, it must be defined in a block conditional operator, which checks the connection state of the FeatureState functionality.

Client-side JavaScript

// Method that defines additional functionality. someMethod: function() ( // Checking functionality connection. if (Terrasoft.Features.getIsEnabled( "functionality code")) { ... } // Method implementation. ... }

To improve ease of use, the composition basic circuit presentation models BaseSchemaViewModel method introduced getIsFeatureEnabled. Therefore the method Terrasoft.Features.getIsEnabled can be replaced by this.getIsFeatureEnabled("feature code").

After connecting new functionality, in order for it to appear in the client code and be loaded by the browser on the client side, you need to refresh the page.

Server side C#

For use Feature toggle in diagrams source code on server side in class Terrasoft.Configuration.FeatureUtilities a set of extension methods of the class was implemented UserConnection . The list of extension methods is given in Table 3. The same class declares a list of functionality states FeatureState.

Table 2. - Main methods of the class DataManager

Conditional template for defining additional functionality in program code:

… // A namespace that defines the ability to switch // additional functionality. using Terrasoft.Configuration; ... // Method in which additional functionality will be defined. public void AnyMethod() ( // Check if functionality is enabled. if (UserConnection.GetIsFeatureEnabled( "functionality code")) { // Implementation of additional functionality. } // Method implementation. ... }

Setting the feature state value is done by calling the SetFeatureState method:

UserConnection.SetFeatureState( "functionality code",FeatureState);