Mechanical CE certification standards

One, foreword

The latest version of the low voltage directive and illustrate how to meet the requirements of new instructions, will focus on include test report of CE with the requirements of technical documents, to help manufacturers LVD directive. This article briefly state the general requirements, instructions and then focus on the test requirements, and provide some examples, and illustrates how to comply with the issues related to LVD test.

Second, the scope of LVD

LVD function applies to all itself to use in ac 50 ~ 1000 v voltage range, 75 ~ 1500 v dc motor products, scope of application of this definition refers to the instruction, rather than instructions applicable restrictions (for example, in the use of ac 230 v in the computer, the dangers posed by dc 12 v circuit is also regulated by the LVD).

LVD is applicable to provide for the use of consumer and industrial products, if it is used in industry equipment, instruction also covers manufacturer itself USES products (such as test equipment).

3, CE with the requirements of technical documents

LVD CE system similar to EMC directive, all within the scope of the product must have CE mark, and must be signed by the manufacturer's representative or importer in line with the statement.

Simple declare yourself is not enough to make sure the product is safe (" safe "is defined as not cause casualties and financial personnel or livestock damage), for this reason, LVD statement requires the support of technical documents to prove.

Technical documents shall include:

1, the general description of the machine equipment

2, conceptual design and manufacturing drawings

3, understand the pattern of description and explanation

4, list all or part of the applicable standards, and the countermeasures adopted by the directives described to meet the security point of view

5, the design calculation results, the execution of inspection

6, the test report

Manufacturer must take all the necessary method to ensure the manufacturing process is in conformity with the technical documentation, the contents of the file should be clear evidence of the product on the design point of view, is safe, and can always meet in the process of manufacturing.

Establish safety design a better approach is to first said listed harmonic standards, and test report as evidence. Harmonic standards regularly published in EC Official gazette (Official Journal). Use has been recognised files (such as EN specifications) to prepare files can be determined the people considered the best in the field of its industrial information, not just their own experience. However, the announcement must consider the necessary safety norms, LVD and this specification may be beyond the reach of harmonic standard requirements. In general, if the product clearly within the scope of a EN standard specification, then this EN standard is sufficient.

In order to ensure the sustainability of conform to, manufacturing quality system should be relative to the corresponding parameters of safety evaluation. First of all, is what you have done to each sample before shipping offline test (including the grounding continuity, electrical insulating strength, insulation resistance), secondly, from the results of the tests is to be able to collect related to product safety of key components and materials (critical components and materials), such as fuse, isolation transformers, combustible plastics), according to the EN standard test can identify key components.

Four, security testing

Test, according to a recognised specification is in accordance with the instructions of the technical requirements of the key factors, testing by the manufacturer or manufacturers that have the ability to implement (that is, by a third party agencies perform test or as a consultant).

Choose or off-site testing in our factory, usually according to the conditions of the manufacturer and wishes, and sometimes the buyer's requirements. No matter how, in fact, the most important factor is the reliability of the final result, signing statements people should know that these test results is the basis of legitimate defence, but must be correct and can reproduce. If it is not corrected the results of the measurement instruments or inexperienced people, may not be able to meet these requirements.

For many people, for their part, for the product testing experience only from EMC directive, LVD directive test is a bit different, in a nutshell, EMC test is a case for defined method, the limiting value measurement, but some are LVD test data collection, to support a more subjective judgment, usually LVD test standard is very complicated, the requirements of the test results and conclusions is required, and the file is usually very thick.

Fifth, the principle of safety

For electric products, most of the LVD EN standard to follow the same basic safety principles. Test is to ensure the normal operation and error conditions of safe operation, these may contain the operator, the influence of the onlookers and service personnel, depends on environment and the specification limits, so that all can be predicted and reasonable operation mode, operation of the environmental conditions into consideration, it is worth noting that exposed to dangerous accident situation should cover, and suicide or careless behavior is not within the scope.

The key factor to product safety is:

1, the appropriate isolation system and insulating barrier, to protect to prevent the risk of electric shock

2, try to reduce the risk of fire, use low flammable components and fireproof material, to protect against the danger of fire

3, the appropriate regulation, in order to protect to prevent dangerous machinery

4, through regulation and enclosure to protect prevent leaked radioactive equipment and the same dangerous (such as X-ray, microwave)

5, through enclosure, chemical or gas seal, in order to protect the prevent dangerous chemicals

6, through barriers and protective components, in order to protect the protection from exposure to risk energy (high current)

Sixth, the normal operating state

Products at design time, often use a combination of some components to produce new features, these components are connected in an enclosure, to form the final product, to ensure that the finished products under normal operation safety, components and materials safety approval rating and any existing files, must be taken. Previously tested or approved to justify in the test report, as the content of the technical documentation or reference.

All the documents required in the new enclosed environment subject, if possible, increase the temperature of the surrounding, for example, the test should cover the temperature measurement and the leakage flow rate test, must additional considerations that materials used in components and electrical isolation or fire protection, may also need to do environmental testing (such as vibration or waterproof (IP) tests). The details of the specific test project, can be found in the applicable product standards.

Seven or more recognized component selection

Many components that are EN standards recognized, however, as far as possible to the manufacturer for approval certificate, test report or certificate copy, if you use the non-eu recognized certificate authentication system, must be sure that is associated with IEC reference standards, to determine compliance with the necessary safety requirements. For example, UL and CSA requirements may be different with the IEC or EN.

Eighth, not the normal operating state

Most product safety standards to allow any single component failure, in this case, the device should be able to continue by security operations, or through a protective components (e.g., fuses, PTC or hot work cut-out) action and can safely failure (safe - failure), due to the improper protection component selection contains the danger of fire and electric shock caused by (due to thermal insulation safety recession).

Protection components need to be able to correctly action, and in the worst mistake case also can protect the equipment, it is important to note that some product standards require protection module is installed inside the equipment, if allowed to use in the external protection, the types and characteristics of component did must be specified.

To protect the transformer secondary circuit fuse is a very good example of protective components, if not properly check the time characteristic of the fuse (for example: a recognised fuse may allow 1.5 or 2 times rated current through, it took 30 minutes to action), in a dangerous condition, transformer burn is common in the fuse before action.

Further on thermal protection, for example, is as follows: in the equipment of the functioning of the motor, carefully choose the thermal cut-out, in order to prevent in the condition of normal use of the peak, unnecessary tripping, and also can in error state (such as: deadlock gear/drive or load) to provide security protection.

Nine, space parameters

The structure of the equipment must be associated with the arrangement of enclosure body components, testing, and to determine the measurement of the space of the adjacent to did not reduce the safety of components (for example, if component should not be to move period, will create the safety barrier arranged).

For users, accessibility assessment of the danger area is another important factor, the product standard specifies a test needle bar and, in order to achieve this purpose, carefully check the ventilation could size is necessary, because these holes are inadvertently come into contact with dangerous moving parts or electrical parts.

Safety switch or safety monitoring is the third example space security parameters, pay special attention to all kinds of the interlock device and their operating system, the designers more often use software logic circuit protection, but many product standards are not decided that this approach can provide comprehensive security, in the same way, the monitoring system must be firmly in place, and in a variety of use cases to be expected all are effective, the use of the interlock or monitoring protection can be equipment users and service staff know.

Ten, to establish a set of test methods in the future

The first step is to select the relevant test standards, to the aforementioned factors, makes a preliminary inspection of product, the main purpose is to establish normal and abnormal operating mode, scope of components within the environment of the basic conditions and structure.

This way method enables you to build a complete test plan, and the priorities of the test. To define the structure and component of EMC requirements, and identify any problems occur during the process of testing the potential conflict, is a good point.

Remember that many of the complexity of the product range, start as early as possible the checker is worth it, if you choose a third party agencies perform tests, so must keep test records, to ensure the schedule meet, finally to determine the conclusion of test plan, can be used in your manufacturing quality systems.

In conformity with the LVD test is not a simple process, product standards have been developed for many years, and a wide range of vendors can fully understand, now phase, whether manufacturers have achieved or LVD directive has yet to recognize, in order to ensure the safety of the product, should be worth the investment of time to make sure the products can accord with the requirement of LVD directive.