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The choice of devices for protecting medium voltage electrical networks. Calculation and selection of protection devices. Rules for the use of protective equipment used in electrical installations

Type approval is carried out in order to ensure the uniformity of measurements. All measuring instruments used in the field of state regulation of ensuring the uniformity of measurements are subject to mandatory approval. At approval of the type of measuring instruments, accuracy indicators are established, as well as the interval and methodology for verifying measuring instruments of this type. The decision on type approval is made by ROSSTANDART (Federal Agency for Technical Regulation and Metrology) based on positive test results for type approval purposes.

The procedure for testing measuring instruments and standard samples is regulated by:

Lab 009 offers testing for type approval purposes measuring instruments and is a structural subdivision of FSUE VNIIMS, which allows using all the possibilities of the institute: the archives of the Federal Information Fund, the database of regulatory documents.

The laboratory offers a client-oriented approach: the implementation of the entire range of work on type approval, efficiency, short deadlines for passing documents. All resulting documents meet the requirements of MI 3290-2010 and regulatory documents of Rostekhregulirovanie.

We carry out tests in order to approve the type of measuring instruments, including medical ones,:

  • testing of complexes of measuring bioanalytical
  • testing devices for polymerase chain reaction, including real-time, DNA amplifiers, PCR analyzers
  • tests of genomic analyzers
  • testing of probe and electron transmission microscopes in biological research
  • tests of mass spectrometers for determining the molecular weights of peptides and proteins
  • testing of biochemical analyzers
  • cycler testing
  • sequencer tests

Testing services for the purpose of type approval of measuring instruments consist in the preparation, conduct and execution of test results in accordance with the requirements of MI 3290-2010. Based on the test results, Rosstandart makes a decision on issuing a certificate of approval of the type of measuring instruments and entering the measuring instruments into the Federal Register of measuring instruments.

Testing work for purposes approval of the type of measuring instruments include:

  • Metrological examination of technical documentation for the device, registration of an application for testing;
  • Development of draft documents for testing;
  • Type descriptions, test programs, verification methods;
  • Organization and conduct of tests;
  • Registration of test results - test reports and test report, approval of the test program, corrected descriptions of the type and verification methodology;
  • Support of documents at the stage of metrological examination of the department of scientific and methodological foundations of the Federal State Unitary Enterprise "VNIIMS";
  • Accompanying documents to Rosstandart;
  • Inclusion by Rosstandart of a measuring instrument in the State Register of Measuring Instruments (Federal Information Fund for Ensuring the Uniformity of Measurements).

Validity period of the certificate of approval of the MI type in mass production is five years, in the case of type approval of a single SI, the certificate is indefinite.

In serial production, the period of validity of the type approval certificate can be extended without testing for another 5 years (provided that the MI design has not been changed and there have been no claims from citizens to this MI over the previous 5 years).

DOCUMENTS REQUIRED FOR MI TESTING FOR THE PURPOSE OF TYPE APPROVAL

The presence of factory calibration protocols or acceptance tests can significantly reduce the time and cost of work!

Approval of the type of measuring instruments (SI) is one of the key services provided by Alira. The organization has for the purpose of type approval, which implies that the specialists involved in this area have all the necessary theoretical knowledge and practical skills required for a full-fledged testing of measuring instruments and the formation of an informed decision, including approval of the MI type.

Testing of measuring instruments: key features

The legislative framework Russian Federation implies the regulation of the compliance of the accuracy of measuring instruments used for industrial and scientific purposes with generally accepted standards in this direction. All new equipment undergoes an appropriate check, known as “testing of measuring instruments for the purpose of type approval”, and in case of a positive result, it is entered into a special State Register, which is confirmed by a legally approved certificate (metrological certificate).
Testing of measuring instruments includes a cycle of work to determine the metrological and technical parameters of these devices.

Particular attention is paid to indicators such as:

  • actual indicators of accuracy in comparison with the reference ones;
  • relative deviations in measurements when they are repeated;
  • intervals and methods of verification of the considered types of measuring instruments.

The above procedure can only be carried out by organizations that have state accreditation and appropriate permission to conduct this type of activity. Among such structures is the company "Alira", professionally providing these services for many years. You can get acquainted with the scope of accreditation of our company.

Approval of the type of measuring instruments: main theses

The MI type approval by Alira is carried out in strict accordance with all the provisions of the technical documentation governing all issues in this field of activity. The accuracy and basic functionality of measuring instruments should not be affected by external influences.

Passing tests and approving the type of measuring instruments allows the owners of the tested equipment to be issued an appropriate certificate (metrological certificate), which is proof of the suitability of the instruments for further operation in laboratory and field conditions.

Speaking of general requirements to the aforementioned devices, the following indicators should be highlighted:

  • fire and electrical safety;
  • resistance to temperature and humidity changes;
  • the presence of protection against external mechanical damage;
  • waterproof, dustproof and more.

Remember that in the territory of the Russian Federation it is allowed to use only approved measuring instruments. And if you need a quick passage of this procedure, please contact the metrological service of our company.

To provide services, please contact us by phone.

Approval of the type of measuring instruments– technologically difficult process, the implementation of which requires certain skills and a deep understanding of the specifics of such an event from the employees of the metrological center. An equally important role is played by the availability of modern laboratory equipment, with the help of which testing of measuring instruments will be carried out for the purpose of type approval.

Testing of measuring instruments for type approval regulated by state standards and controlled by metrological services. The main goal of such an event is to ensure the uniformity of measurements throughout the Russian Federation, as well as control over the stages of production of measuring instruments and the compliance of manufactured products with established technical and operational standards.

Today, there are many methods for testing SI. The choice of the appropriate one depends on several factors, the main ones being the dimensions and design features of the measuring instruments, as well as their intended purpose. In order to issue a Certificate of Approval of the Type of Measuring Instruments, it is necessary to perform a number of actions, the general purpose of which is to prove the compliance of the technical documentation and the actual characteristics of the tested samples with the requirements normative documentation regulating the process of production and operation of a particular type of product.

The presence of impeccable results during all stages of the test allows you to make a decision on the approval of the type of measuring instruments and issue an accompanying Certificate in Moscow or another locality of the Russian Federation. It is noteworthy that the process can be carried out only in one of the representative offices of accredited metrological centers, whose employees are entitled to provide such a service as testing measuring instruments in order to approve their type. The period of validity of the document is set on an individual basis and comes into force from the moment of its issuance.

Testing of measuring instruments for the purpose of type approval

This process consists of many steps, such as:

  • study of technical documentation for SI, execution and acceptance into work of an application for conducting relevant tests;
  • creation and gradual completion of specialized documentation in the course of the implementation of the above process;
  • preparation of equipment, approval of the test program;
  • direct testing in specialized laboratories using professional equipment and with the involvement of highly qualified personnel of the appropriate profile;
  • documenting test results, support of documents, their entry into the state register.

The implementation of all these procedures allows you to draw up and issue a document on approval of the MI type to the direct customer.

To test measuring instruments for type approval in Moscow, you can contact the specialized metrological center "Autoprogress-M". You only need to call us or leave a request.

Electrical appliances and wiring must be protected from possible emergency situations by protective devices, this is a short circuit, connecting an increased load, overvoltage. The main functions of protecting people and electrical wiring in a residential building are performed by VA(automatic switches), RCD (), VD(differential switches), SPD, RPN ().

Automatic switch (VA)

The calculation and selection of protection devices is the basis for designing the power supply of a private house. Their main function is to protect against overcurrent short circuits ( KZ) and when the increased load is switched on. From short circuit provided electromagnetic release, from increased power intended thermal release.

When a consumer chooses VA, he must know that each electrical appliance there is starting current. This is electricity, which is more than the nominal (working) by a certain amount. This value can exceed 3, 5 or 7 times the rated current of the appliance. The inrush current transit time is a few milliseconds. But even this time is enough for the electromagnetic release to work and the VA to turn off the electrical network. For this reason, circuit breakers are divided into several types depending on the magnitude of the starting currents.

  • Type AT– (from 3 – 5) In, where In is the rated (working) current of the electrical device.
  • Type With– (5 – 10) In
  • Type D– (10 – 20) In

For example, you need to install VA for induction motor. For some types, the starting current is 6 In, so we choose VA, and its type is B, and so on.

When choosing machines by type, that is, by starting current, it is necessary to take into account some nuances. So ABB machines are classified according to IEC 60947 - 2 ( international standard), where the class To(8 - 14) In, a class Z(2 – 4) In.

The principle of operation of the thermal and electromagnetic release

Fig.1

Housing VA ( 1 ) are made of a dielectric material, like the handle ( 2 ), which serves to enable it. Retainer ( 3 ) is designed for mounting on a DIN rail with an ordinary screwdriver (you bend it and install or remove the VA). Bimetallic plate (6) is the main element of VA for protection against increased load. Its essence is that it is made of a special alloy and has special physical and technical characteristics, and when a current passes through it, which is greater than the working (rated) current, it bends. As a result of this bending, it acts on the element ( 7 ) and VA disconnects the electrical network. These are actions thermal release.

If over currents (short circuits) appear in the electrical network, then they pass through the solenoid ( 9 ), it draws in the core and the VA is turned off. These are actions electromagnetic release.

The main postulates when choosing VA for a household consumer

  • When a consumer buys a circuit breaker in a store, first of all he must know the long-term permissible current of the cable that he will protect.
  • When choosing protection devices (VA) according to the thermal release, it is necessary to take into account the non-shutdown current 1.13 In. Even if the load exceeds the rated current by 1.11 times, the thermal release will not work, and if this current is applied to the wire for a long time, this can lead to undesirable consequences.
  • Coefficient 1.45 relative to the rated current takes into account when the circuit breaker trips. For VA, this time is about 1 hour, but it depends on many factors, the external environment, the manufacturer, the number of machines that are located. During this time, the cable insulation may melt. Consider this factor when choosing VA according to the rated current relative to the continuously admissible current of the outgoing cable.

According to the number of poles, VAs are divided into one, two, three and four poles. They also choose VA according to the degree of protection, the number of contacts, the type of installation, the presence of current limitation, and so on.

Rated currents circuit breakers are located on outdoor panel. Main line for household VA 6.3, 10, 16, 20, 25, 32, 40, 63 A there are more.