Iec 60068-2-2-2007.Pdf

IEC 60068 2 2 Edition 5 0 2007 07 INTERNATIONAL STANDARD NORME INTERNATIONALE Environmental testing – Part 2 2 Tests – Test B Dry heat Essais d’environnement – Partie 2 2 Essais – Essai B Chaleur sèch[.]

General

The temperature chamber(s) shall be constructed and verified in accordance with specifications IEC 60068-3-5 and IEC 60068-3-7

Further guidance for the dry heat and cold tests can be found in IEC 60068-3-1, and general guidance in IEC 60068-1

A specimen is classified as heat-dissipating when its hottest surface point, measured under free air conditions with low air velocity, exceeds the ambient temperature by more than 5 K after achieving temperature stability.

4.8 of IEC 60068-1) When the relevant specification calls for a storage or transportation test or does not specify an applied load during the test, the Dry Heat Test Bb will apply.

Ascertaining high or low air velocity in the test chamber

Under standard atmospheric conditions for testing (refer to IEC 60068-1) with an air velocity of less than 0.2 m/s, the specimen must be powered on or electrically loaded according to the specified high temperature for the test.

Once the specimen has achieved temperature stability, the temperature at several representative points on or around the specimen must be measured with an appropriate monitoring device The temperature increase at each point should then be recorded.

Once the chamber air flow is activated and temperature stability is reached, the temperatures at representative points are measured again If these temperatures differ by more than 5 K (or a specified value) from those recorded without air flow, this discrepancy will be documented in the test report, indicating that the test chamber exhibits high velocity circulation Subsequently, the specimen is turned off, and all loading conditions are removed.

LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU.

Application of tests with sudden change of temperature versus tests with

In Tests Bb, Bd, and Be, the specimen is placed in a test chamber initially set to laboratory temperature The chamber's temperature is then gradually increased to avoid any harmful effects on the test specimen caused by the temperature change.

Testing of heat-dissipating specimens

Tests Bd and Be outline methods for evaluating heat-dissipating specimens under conditions of low air velocity circulation This approach enables the formation of localized hot spots within the specimen, mirroring the conditions found in actual installed applications.

Temperature monitoring

Air temperature in the chamber must be measured using sensors positioned far enough from the specimen to minimize the impact of heat dissipation It is essential to implement appropriate measures to prevent heat radiation from influencing these temperature readings For further details, refer to IEC 60068-3-5.

Packaging

For storage and transportation tests, equipment may be tested with its packaging in place

In steady state tests, the equipment will stabilize at the chamber's temperature, and packaging should be removed unless specified otherwise or if heating elements are included in the package.

Diagrammatic representations

To facilitate the choice of test method, a diagrammatic representation of the various procedures is given in Figure 1

Figure 1 – Block diagram Tests B: Dry Heat

General

Tests Bb, Bd, and Be are similar Differences are noted in Subclauses 5.2.2, 5.3.2 and 5.4.2

The tests maintain consistency from Clause 6 onward, stipulating that the temperature change within the chamber must not exceed 1 K per minute, averaged over a maximum duration of 5 minutes Additionally, the relevant specification will outline the operational parameters of the specimen being tested.

Care shall be taken that any cooling devices of the specimen are in accordance with the prescription in the relevant specification.

Test Bb: Dry heat for non heat-dissipating specimens with gradual change of temperature

Object

This procedure is for non heat-dissipating specimens which are subjected to an elevated temperature for a time long enough for the specimen to achieve temperature stability

General description

The specimen is introduced into the chamber, which is at the temperature of the laboratory

The temperature is adjusted according to the specified severity level, and once stability is achieved, the test specimen is subjected to these conditions for the required duration For operational specimens, power is applied, and functional tests are conducted as needed Additional stabilization may be required before exposing the specimen to high-temperature conditions for the specified time.

Specimens under test are normally in non-operating conditions

High air velocity circulation is normally used for this test.

Test Bd: Dry heat for heat-dissipating specimens with gradual change of

Object

This procedure is for heat dissipating specimens which are subjected to an elevated temperature for a time long enough for the specimen to achieve temperature stability.

General description

A test may be conducted to verify whether the test facility meets the criteria for a low air velocity chamber The specimen is placed inside the chamber, initially set to the laboratory temperature, before being adjusted to the specified severity temperature outlined in the relevant standards.

Low air velocity circulation is normally used for this test.

Energising the specimen

The specimen shall then be switched on or electrically loaded and checked to ascertain whether it is capable of functioning in accordance with the relevant specification

The specimen shall remain in the operating condition in accordance with the duty cycle and at the loading condition (if applicable) as prescribed by the relevant specification

Once the test specimen achieves temperature stability, it is subjected to the specified conditions for the duration outlined in the relevant standards, typically utilizing low air velocity circulation during the test.

Test Be: Dry heat for heat-dissipating specimens with gradual change of

Object

This procedure outlines the testing of heat-dissipating specimens exposed to elevated temperatures for a sufficient duration to reach thermal stability, while ensuring they remain powered during the entire testing period.

General description

A test may be conducted to verify if the facility meets the standards for a low air velocity chamber The specimen is placed in the chamber at laboratory temperature, then powered on or electrically loaded to ensure it operates according to the specified requirements.

The specimen shall remain in the operating condition in accordance with the duty cycle and at the loading condition (if applicable) as prescribed by the relevant specification

The temperature is then adjusted to the temperature appropriate to the degree of severity as specified in the relevant specification

After temperature stability of the test specimen has been reached, the specimen is exposed to these conditions for the specified duration

The relevant specification shall define the functioning of the specimen under test

Low air velocity circulation is normally used for this test

Confirmation of performance

IEC 60068-3-5 provides guidance for the confirmation of performance of temperature test chambers IEC 60068-3-1 provides general guidance for the performance of tests A and B

The chamber shall be large enough compared with the size and amount of heat-dissipation of the test sample.

Working space

The dimensions of the test sample shall be such that it is entirely within the working space of the test chamber

The air temperature delivered to the test specimen must remain within ± 2 K of the specified test severity temperature during steady state conditions Additionally, the air temperature in the working space should be measured as outlined in Subclause 4.5.

In cases where the chamber size prevents maintaining specified tolerances, adjustments may be made to ±3 K up to 100 °C, ±5 K from 100 °C to 200 °C, and ±10 K from 200 °C to 315 °C It is essential to document the tolerance applied in the test report, and users must also indicate the tolerance achieved for temperatures exceeding 315 °C.

Thermal radiation

To minimize the specimen's heat transfer through thermal radiation, it is essential to shield any heating or cooling elements from the specimen Additionally, maintaining uniform temperature across the chamber surfaces, in line with the conditioning air, is crucial.

Mounting

The specifications must detail the thermal conduction and other essential characteristics of the mounting and connections for the test specimen Testing should be conducted using the specific mounting devices intended for the test specimen's use.

Severities

General

The severities, determined by temperature and exposure duration, must adhere to the relevant specifications They should be selected from the values outlined in sections 6.5.2 and 6.5.3, derived from the known environment if it yields significantly different values, or obtained from other credible data sources, such as IEC 60721.

Temperature

Duration

When conducting tests related to endurance or reliability, it is essential to refer to IEC publications that provide specific recommendations for test durations.

Preconditioning

The relevant specification may call for a preconditioning.

Initial measurements

The initial state of the specimen shall be known This may be achieved by visual inspection, and/or functional tests as required by the relevant specification.

Conditioning

Steady state conditions

The specimen shall then be exposed to the high temperature conditions for the duration as detailed in the relevant specification

In exceptional cases where the specimen fails to achieve temperature stability, the test duration begins when the specimen is energized This situation often arises with specimens that have long duty cycles.

Absolute humidity

The absolute humidity shall not exceed 20 g of water vapour per cubic metre of air

(corresponding to approximately 50 % relative humidity at 35 ºC) the relative humidity shall not exceed 50 %.

Intermediate measurements

The relevant specification may require loading and measurements to be conducted during or after conditioning while the specimen remains in the chamber If these measurements are necessary, the specification must clearly define the specific measurements and the timing for their execution, ensuring that the specimen is not removed from the chamber during this process.

To assess the performance of the specimen type before the completion of the designated duration, an additional lot must be obtained for each specified duration It is essential to conduct recovery and final measurements separately for each lot.

Final temperature ramp

During testing, if the specimen is under operational or loaded conditions, it must be switched off or unloaded before the temperature is decreased, except for test Be, where the specimen should remain operational throughout the recovery period.

At the conclusion of the designated time, the specimen will stay in the chamber while the temperature is gradually decreased to a level that falls within standard atmospheric testing conditions The temperature change rate in the chamber must not exceed 1 K per minute, averaged over a maximum duration of 5 minutes.

Recovery

The specimen shall be subjected to the recovery procedure in the chamber or otherwise as appropriate

The specimen shall then remain under standard atmospheric conditions for recovery for a period adequate for the attainment of temperature stability, with a minimum of 1 h

If required by the relevant specification, the specimen shall be switched on or loaded and measured continuously during the recovery period

If the standard conditions given above are not appropriate for the specimen to be tested, the relevant specification may call for other recovery conditions.

Specimen with artificial cooling

The specification must outline the properties of the coolant used for the specimen When utilizing air as the coolant, it is essential to ensure that the air remains free from oil contamination and is sufficiently dry to prevent moisture-related issues.

Final measurements

The specimen shall be visually inspected and such performance checks as are required by the relevant specification

7 Information to be given in the relevant specification

When including this test in the relevant specification, it is essential to provide applicable details such as preconditioning, initial measurements, mounting or support specifics, the specimen's state including the cooling system during conditioning, exposure severity, temperature, and duration, the rate of temperature change, measurements or loading during conditioning, any non-standard recovery, final measurements, deviations in procedure agreed upon by the customer and supplier, and the temperature difference if low air velocity was not established.

8 Information to be given in the test report

As a minimum, the test report shall show the following information:

2 Test laboratory (name, address and details of accreditation - if any)

4 Type of test (Bb, Bd, or Be)

5 Purpose of test (development, qualification etc.)

6 Test standard, edition (IEC 60068-2-2, edition *)

7 Relevant laboratory test procedure (code and issue)

8 Test specimen description (unique id, drawing, photo, quantity build status, etc.)

9 Test chamber identity (manufacturer, model number, unique id, etc.)

10 Performance of test apparatus (set point temperature control, air flow, etc.)

11 Air velocity and direction (air velocity and direction of incident air to the specimen)

13 Calibration data (last and next due date)

14 Initial, intermediate and final measurements

15 Required severities (from test specification)

16 Test severities (measuring points, data, etc.)

17 Performance of test specimens (results of functional tests, etc.)

18 Observations during testing and actions taken

NOTE A test log should be written for the testing which can be attached to the report

4 Application des essais de spécimens ne dissipant pas d’énergie par rapport aux essais de spécimens dissipant de l’énergie 22

4.2 Vérification de la haute ou faible vitesse de l’air dans la chambre d’essai 22

4.3 Application d’essais avec variation brusque de la température par rapport aux essais avec variation lente de la température 23

4.4 Essai de spécimens dissipant de l’énergie 23

5.2 Essai Bb: Chaleur sèche pour spécimens ne dissipant pas d’énergie avec variation lente de la température 24

5.3 Essai Bd: Chaleur sèche pour spécimens dissipant de l’énergie avec variation lente de la température lorsqu’ils ne sont pas mis en fonctionnement durant l’essai 25

5.4 Essai Be: Chaleur sèche pour spécimens dissipant de d’énergie avec variation lente de la température lorsqu’ils sont mis en fonctionnement durant l’essai 25

7 Renseignements que doit fournir la spécification particulière 29

8 Renseignements que doit fournir le rapport d’essai 29

Figure 1 – Diagramme complet des essais B: Chaleur sèche 24

ESSAIS D’ENVIRONNEMENT – Partie 2-2: Essais – Essai B: Chaleur sèche

The International Electrotechnical Commission (IEC) is a global standards organization comprising national electrotechnical committees Its primary goal is to promote international cooperation on standardization in the fields of electricity and electronics To achieve this, the IEC publishes international standards, technical specifications, technical reports, publicly accessible specifications (PAS), and guides, collectively referred to as "IEC Publications." The development of these publications is entrusted to study committees, which allow participation from any interested national committee Additionally, international, governmental, and non-governmental organizations collaborate with the IEC in its work The IEC also works closely with the International Organization for Standardization (ISO) under an agreement between the two organizations.

Official decisions or agreements of the IEC on technical matters aim to establish an international consensus on the topics under consideration, as the relevant national committees of the IEC are represented in each study committee.

The IEC publications are issued as international recommendations and are approved by the national committees of the IEC The IEC makes every reasonable effort to ensure the technical accuracy of its publications; however, it cannot be held responsible for any misuse or misinterpretation by end users.

To promote international consistency, the national committees of the IEC commit to transparently applying IEC publications in their national and regional documents as much as possible Any discrepancies between IEC publications and corresponding national or regional publications must be clearly stated in the latter.

5) La CEI n’a prévu aucune procédure de marquage valant indication d’approbation et n'engage pas sa responsabilité pour les équipements déclarés conformes à une de ses Publications

6) Tous les utilisateurs doivent s'assurer qu'ils sont en possession de la dernière édition de cette publication

The IEC and its administrators, employees, agents, including specialized experts and members of its study committees and national committees, shall not be held liable for any injuries, damages, or any other type of loss, whether direct or indirect This includes any costs, such as legal fees, arising from the publication or use of this IEC Publication or any other IEC Publication, or from the credit attributed to it.

8) L'attention est attirée sur les références normatives citées dans cette publication L'utilisation de publications référencées est obligatoire pour une application correcte de la présente publication

Attention is drawn to the fact that some elements of this IEC publication may be subject to intellectual property rights or similar rights The IEC cannot be held responsible for failing to identify such property rights or for not indicating their existence.

La Norme internationale CEI 60068-2-2 a été établie par le comité d'études 104 de la CEI:

Conditions, classification et essais d’environnement

Cette cinquième édition de la CEI 60068-2-2 annule et remplace la quatrième édition publiée en 1974 Elle inclut les textes révisés de la quatrième édition, de l’amendement 1 publié en

1993 et de l’amendement 2 publié en 1994

Elle a le statut d’une publication fondamentale de sécurité conformément au Guide CEI 1004

Les principaux changements par rapport à l’édition précédente sont les suivants: Les essais

Ba et Bc ont été retirés puisqu’ils étaient plus sévères que l’essai Nb de la CEI 60068-2-14:

Variations de température Deuxièmement, il a été considéré justifié de supprimer la valeur de

The article highlights that there is a 3% allowance for the temperature difference between the test chamber air and the wall temperatures Additionally, it is now suggested, rather than required, that the test specimen be operational during the testing process Lastly, the appendices have been removed.

Le texte de cette norme est issu des documents suivants:

Le rapport de vote indiqué dans le tableau ci-dessus donne toute information sur le vote ayant abouti à l'approbation de cette norme

Cette publication a été rédigée selon les Directives ISO/CEI, Partie 2

Un liste de toutes les parties de la série CEI 60068, sous le titre général Essais d’environnement, peut être consultée sur le site web de la CEI

The committee has determined that the content of this publication will remain unchanged until the maintenance date specified on the IEC website at "http://webstore.iec.ch" in the data related to the publication in question On that date, the publication will be updated.

• remplacée par une édition révisée, ou

ALIGNEMENT DES INDICES DES ESSAIS A: FROID,

ET DES ESSAIS B: CHALEUR SÈCHE

L’alignement des indices des essais A: Froid, et des essais B: Chaleur sèche, est donné dans le tableau suivant:

Essais A: Froid Essais B: Chaleur sèche

Vitesse de l’air Type de spécimen

Vitesse de l’air a Retiré Retiré b Ne dissipe pas

Progressive Elevée de préférence c Retiré Retiré d Haute dissipation

Dissipe Progressive Faible de préférence e Haute dissipation fournie partout

ESSAIS D’ENVIRONNEMENT – Partie 2-2: Essais – Essai B: Chaleur sèche

This standard addresses dry heat testing applicable to both energy-dissipating and non-energy-dissipating specimens The Bb and Bd tests for non-energy-dissipating specimens show no significant changes compared to previous editions.

Le but de l’essai de chaleur sèche se limite à la détermination de l’aptitude des composants, équipements ou autres articles à être utilisés, transportés ou stockés à haute température

Dry heat tests do not assess the ability of specimens to withstand or operate during temperature fluctuations Therefore, it is essential to utilize test N of IEC 60068-2-14: Temperature Variations.

Les essais de chaleur sốche se subdivisent de la faỗon suivante:

Essai de chaleur sèche pour spécimens ne dissipant pas d’énergie

– avec variation lente de la température, Bb

Essais de chaleur sèche pour spécimens dissipant de l’énergie

– avec variation lente de la température, Bd;

– avec variation lente de la température, pour les spécimens dissipant partout, Be

La procédure décrite dans cette norme est normalement prévue pour les spécimens qui atteignent la stabilité thermique pendant le déroulement de l’essai

CEI 60068-1:1988, Essais d'environnement – Partie 1: Généralités et guide

CEI 60068-3-1, Essais d'environnement – Partie 3: Informations de base – Section un: Essais de froid et de chaleur sèche

CEI 60068-3-5, Essais d'environnement – Partie 3-5: Documentation d'accompagnement et guide – Confirmation des performances des chambres d'essai en température

CEI 60068-3-7, Essais d'environnement – Partie 3-7: Documentation d'accompagnement et guide – Mesures dans les chambres d'essai en température pour les essais A et B (avec charge)

CEI 60068-5-2, Essais d'environnement – Partie 5-2: Guide pour la rédaction des méthodes d'essais – Termes et définitions

CEI 60721 (toutes les parties), Classification des conditions d’environnement

Pour les besoins de ce document, les définitions de la CEI 60068-5-2 s’appliquent ainsi que les suivantes:

In a workspace, the air velocity should be low enough to maintain optimal conditions, ideally below 0.5 m/s, to ensure that the temperature of the test specimen does not decrease by more than 5 K due to air circulation.

The high air velocity in the workspace facilitates optimal testing conditions by effectively reducing the temperature of the specimen by more than 5 K through the influence of air circulation.

4 Application des essais de spécimens ne dissipant pas d’énergie par rapport aux essais de spécimens dissipant de l’énergie

Généralités

La ou les chambres d’essai en tempộrature doivent ờtre conỗues et vộrifiộes selon les spécifications de la CEI 60068-3-5 et la CEI 60068-3-7

D’autres conseils pour les essais de froid et de chaleur sèche peuvent être trouvés dans la

CEI 60068-3-1 et des conseils généraux dans la CEI 60068-1

A specimen is deemed to dissipate energy when the temperature at its hottest point, measured under calm air conditions (i.e., with low air circulation speed), exceeds the surrounding atmospheric temperature by more than 5 K after thermal stability has been reached (refer to IEC 60068-1, 4.8) If the specific requirements dictate a storage or transport test or do not specify dissipation conditions during the test, the dry heat test Bb will be applied.

Vérification de la haute ou faible vitesse de l’air dans la chambre d’essai

Under normal atmospheric conditions for measurements and testing (refer to IEC 60068-1), with an air velocity of less than 0.2 m/s, the specimen must be powered or subjected electrically to dissipation conditions as specified for the high temperature at which the test is conducted.

Once the thermal stability of the specimen is achieved, the temperature at several representative points around or above the specimen must be measured using appropriate control equipment The resulting temperature increase at each point should be recorded.

The airflow in the chamber is activated, and once temperature stability is achieved, the temperatures at representative points must be measured again If the temperatures differ by more than 5 K (or a specified value) from those measured without airflow, this discrepancy should be recorded in the test report, indicating that the test chamber has high-speed air circulation The specimen is then halted, and the dissipation conditions are removed.

Application d’essais avec variation brusque de la température par rapport

essais avec variation lente de la température

In the Bb, Bd, and Be tests, the specimen is initially placed in a chamber at laboratory temperature The temperature in the chamber is then gradually increased to prevent any destructive effects on the specimen caused by rapid temperature changes.

Essai de spécimens dissipant de l’énergie

The Bd and Be tests outline the procedures for testing energy-dissipating specimens under low air velocity conditions This approach facilitates the development of localized hot spots within the specimen, similar to those that may occur in installed applications.

Surveillance de la température

The air temperature in the test chamber must be measured using temperature sensors positioned at a distance from the specimen to minimize the impact of heat dissipation It is advisable to take appropriate precautions to prevent heat radiation from influencing these measurements For further information, please refer to the relevant guidelines.

Emballage

For storage and transport testing, equipment can be evaluated with its packaging intact However, since these tests are conducted under continuous conditions, the equipment will eventually stabilize at the test chamber's temperature The packaging should be removed unless specific requirements dictate that it must remain or if heating elements are included within it.

Représentations par diagrammes

Pour faciliter le choix de la méthode d’essai, une représentation des diverses procédures par un diagramme est donnée à la Figure 1

En fonctionnement durant le temps de l’épreuve?

Figure 1 – Diagramme complet des essais B: Chaleur sèche

Généralités

Les essais Bb, Bd et Be sont similaires Les différences apparaissent en 5.2.2, 5.3.2 et 5.4.2

All other sections of the tests remain unchanged from Article 6 The temperature variation in the test chamber must not exceed 1 K per minute, averaged over a period not exceeding 5 minutes The specific requirements should outline the operation of the specimen being tested.

Des précautions doivent être prises pour que tout matériel de refroidissement du spécimen soit en accord avec les prescriptions de la spécification particulière.

Essai Bb: Chaleur sèche pour spécimens ne dissipant pas d’énergie avec

Objet

This procedure applies to specimens that do not dissipate energy and are subjected to high-temperature conditions for a sufficient duration to achieve thermal stability.

Description générale

Le spécimen est introduit dans la chambre, qui est à la température ambiante du laboratoire

The chamber temperature is adjusted to the severity level specified in the particular specification Once thermal stability of the specimen is achieved, it is maintained under these conditions for the specified duration For specimens requiring operation, even if they do not meet energy dissipation requirements, they must be powered on, and functional testing is conducted as needed An additional stabilization period may be necessary, during which the specimen should be exposed to high-temperature conditions for the duration outlined in the particular specification.

Les spécimens en essai sont normalement placés dans des conditions de non- fonctionnement

Une circulation d’air à haute vitesse est normalement utilisée pour cet essai.

Essai Bd: Chaleur sèche pour spécimens dissipant de l’énergie avec

Objet

Cette procédure s’applique aux spécimens dissipant de l’énergie qui sont soumis à des conditions de température élevée pendant une durée suffisante pour que le spécimen atteigne la stabilité thermique.

If necessary, a test is conducted to assess whether the test characteristics meet the requirements of the low-speed wind tunnel The specimen is placed in the chamber, which is initially at the laboratory's ambient temperature The temperature within the chamber is then adjusted to the severity level specified in the particular specification.

Une circulation d’air à faible vitesse est normalement utilisée pour cet essai.

Recharge du spécimen

Le spécimen doit alors être mis sous tension ou soumis électriquement à des conditions de dissipation et contrôlé pour s’assurer qu’il est capable de fonctionner selon la spécification particulière

Le spécimen doit rester dans les conditions de fonctionnement selon son cycle de fonctionnement et les conditions de dissipation (si applicables) comme prescrit dans la spécification particulière

Once the thermal stability of the specimen is achieved, it is subjected to these conditions for the duration specified in the particular specification Typically, a low-speed air circulation is employed for this test.

Essai Be: Chaleur sèche pour spécimens dissipant de d’énergie avec

Objet

This procedure applies to energy-dissipating specimens subjected to high-temperature conditions for a sufficient duration to achieve thermal stability, and which are operated during the testing period.

If necessary, a test is conducted to determine whether the test characteristics meet the requirements of the low-speed wind tunnel The specimen is placed in the chamber, which is maintained at the laboratory's ambient temperature It must then be powered or electrically subjected to dissipation conditions and monitored to ensure it operates according to the specific specifications.

Le spécimen doit rester dans les conditions de fonctionnement selon son cycle de fonctionnement et les conditions de dissipation (si applicables) comme prescrit dans la spécification particulière

La température dans la chambre est ensuite réglée à la valeur correspondant au degré de sévérité indiqué dans la spécification particulière

Lorsque la stabilité thermique du spécimen est atteinte, celui-ci est soumis à ces conditions pendant la durée spécifiée

La spécification particulière doit définir le fonctionnement du spécimen soumis à l’essai

Une circulation d’air à faible vitesse est normalement utilisée pour cet essai

Confirmation de performance

La CEI 60068-3-5 fournit des conseils pour la confirmation de performance de température des chambres d’essais La CEI 60068-3-1 fournit des conseils généraux pour la performance des essais A et B

La chambre d’essai doit être suffisamment grande comparée à la taille et à la quantité de dissipation d’énergie de l’échantillon d’essai.

Espace de travail

Les dimensions de l’échantillon d’essai doivent être telles qu’il puisse être placé entièrement dans l’espace de travail de la chambre d’essai

The air temperature directed at the test specimen must be maintained within ± 2 K of the specified severity temperature during continuous operating conditions Additionally, the air temperature in the workspace should be measured according to section 4.5.

NOTE Dans le cas ó les dimensions de la chambre d’essai ne permettent pas de maintenir ces tolérances, la tolérance peut être élargie à ±3 K jusqu’à 100 °C, à ±5 K de 100 °C à 200 °C et à ±10 K de 200 °C à 315 °C

Lorsque cela est réalisé, il convient que la tolérance utilisée soit spécifiée dans le rapport d’essai Il convient que l’utilisateur spécifie également la tolérance appliquée pour les températures supérieures à 315 °C.

Radiation thermique

La capacité du spécimen à transférer la chaleur par radiation thermique doit être minimisée

This may involve inspecting all heating and cooling elements of the specimen, ensuring that parts of the test chamber surfaces do not significantly differ in temperature from the air during the test.

Montage

It is advisable to specify the thermal condition and other relevant characteristics of the assembly and connections of the test specimen in the particular specification When the test specimen is intended for use with specific mounting equipment, that equipment should be utilized for the testing.

Sévérités

Généralités

The severities, determined by temperature and exposure duration, must be specified in the particular specification They should be a) selected from those indicated in sections 6.5.2 and 6.5.3; b) derived from the known environment if it provides significantly different values; or c) inferred from other recognized sources based on relevant data.

Température

Durée

When conducting endurance or reliability tests, it is essential to consider the IEC publications that provide specific recommendations regarding the duration of these tests.

Pré-conditionnement

La spécification particulière peut prescrire un pré-conditionnement.

Mesures initiales

L’état initial du spécimen doit être connu Celui-ci peut être déterminé par une inspection visuelle, et/ou par des essais fonctionnels tels que décrits dans la spécification particulière.

Conditionnement

Conditions en régime continu

Le spécimen doit ensuite être exposé à des conditions de basse température durant le temps précisé dans la spécification particulière

In exceptional cases where the specimen does not achieve thermal stability, the testing duration begins when the specimen is under load Such instances are typically caused by specimens with long operating cycles.

Humidité absolue

L’humidité absolue ne doit pas dépasser 20 g de vapeur d’eau par mètre cube d’air

(correspondant approximativement à 50 % d’humidité relative à 35 °C) l’humidité relative ne doit pas dépasser 50 %.

Mesures intermédiaires

The specific specification may outline conditions for dissipation and/or measurements during or at the end of the test while the specimen remains in the chamber If such measurements are necessary, the specification must clearly define them and the timing for their execution The specimen must not be removed from the chamber until all measurements are completed.

If one wishes to assess the performance of the specimen before the end of the prescribed duration, it is essential to test an additional batch of specimens for each specified duration It is important that the recovery and final measurements are conducted separately for each batch.

Rampe de température finale

If the specimen remains operational or is subjected to dissipation conditions during the test, it must be powered down or removed from dissipation conditions before the temperature is lowered to the exceptional level of test Be, where the specimen must remain functional throughout the recovery period.

At the end of the specified duration, the specimen must remain in the testing chamber, where the temperature should gradually reach a value within the normal atmospheric conditions for the test The temperature variation in the testing chamber should not exceed 1 K per minute, averaged over a period not exceeding 5 minutes.

Reprise

Le spécimen doit être soumis à la procédure de reprise dans la chambre d’essai ou dans un autre endroit approprié

Le spécimen doit ensuite être soumis aux conditions atmosphériques normales de reprise pendant une durée suffisante pour que la stabilité thermique soit atteinte, avec un minimum de 1 h

If the specific requirements dictate, the specimen must be energized or subjected to dissipation conditions and continuously measured throughout the recovery period.

Si les conditions atmosphériques normales de reprise indiquées ci-dessus ne sont pas appropriées pour le spécimen en essai, la spécification particulière peut prescrire d’autres conditions de reprise.

Spécimen avec refroidissement artificiel

La spécification particulière doit définir les caractéristiques du refroidissant du spécimen

When using air as a coolant, it is crucial to ensure that the air is free from oil contamination and sufficiently dry to prevent mold issues.

Mesures finales

Le spécimen doit être examiné visuellement et soumis aux vérifications électriques et mécaniques prescrites par la spécification particulière

7 Renseignements que doit fournir la spécification particulière

When this test is included in the specific specification, the following details must be specified, as applicable: a) pre-conditioning; b) initial measurements; c) assembly or support details; d) condition of the specimen and cooling system during the test; e) severity, temperature, and duration of exposure; f) variations in temperature changes; g) measurements and/or dissipation conditions during the test; h) recovery if it is not normal; i) final measurements; j) any deviations from the method agreed upon between the client and the supplier; k) temperature difference if the low air speed was not established (see 4.2).

8 Renseignements que doit fournir le rapport d’essai

Au minimum, le rapport d’essai doit donner les informations suivantes:

2 Laboratoire d’essai (nom, adresse et informations sur l’accréditation – si existante)

4 Type d’essai (Bb, Bd ou Be)

5 Objet de l’essai (développement, qualification etc.)

6 Norme d’essai, édition (CEI 60068-2-2, édition *)

7 Procédure d’essai du laboratoire particulière

(code et date de publication)

8 Description du spécimen d’essai (schéma, photo, quantité fabriquée etc.)

9 Identification de la chambre d’essai (constructeur, numéro de modèle, numéro d’identification, etc.)

10 Performance des appareils d’essai (commande des points de température, écoulement de l’air, etc.)

11 Vitesse et direction de l’air (vitesse et direction de l’air amené sur le spécimen)

13 Etalonnage (dernière et prochaine dates)

14 Mesures initiales, intermédiaires et finales

15 Sévérités requises (données par la spécification d’essai)

16 Sévérités d’essai (points de mesure, données, etc.)

17 Performance des spécimens d’essai (résultats des essais fonctionnels, etc.)

18 Observations durant l’essai et actions menées

NOTE Il convient qu’un journal d’essai soit consigné; il peut être joint au rapport

Tiêu đề	Test B: Dry heat
Chuyên ngành	Environmental testing
Thể loại	standards
Năm xuất bản	2007
Thành phố	Geneva

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