【BS英國標(biāo)準(zhǔn)】BS EN 61558-2-8-1999 Safety of small power transformers, power supply units and similar — Part 2-8 Particular requirements for bell and chime

licensed copy: institute of technology tallaght, institute of technology, mon jun 11 16:47:48 gmt+00:00 2007, uncontrolled copy, (c) bsibritish standard bs en61558-2-8:1999iec 61558-2-8:1998safety of small power transformers, power supply units and similar part 2-8: particular requirements for bell and chime transformersthe european standard en 61558-2-8:1998 has the status of abritish standardics 29.180bs en 61558-2-8:1999national forewordthis british standard is the english language version of en 61558-2-8:1998. it is identical with iec 61558-2-8:1998.the bs en 61558 series of standards will ultimately supersede bs 3535-1, dual numbered as bs en 60742:1996, and bs 3535-2. until that time arrives, these latter standards are only to be used for equipment not covered by the bs en 61558 series.the uk participation in its preparation was entrusted to technical committeepel/96, small transformers, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/european committee any enquiries on the interpretation, or proposals for change, and keep the uk interests informed; monitor related international and european developments and promulgate them in the uk.a list of organizations represented on this committee can be obtained on request to its secretary.from 1 january 1997, all iec publications have the number 60000 added to the old number. for instance, iec 27-1 has been renumbered as iec 60027-1. for a period of time during the change over from one numbering system to the other, publications may contain identifiers from both systems.cross-referencesattention is drawn to the fact that cen and cenelec standards normally include an annex which lists normative references to international publications with their corresponding european publications. thebritish standards which implement these international or european publications may be found in the bsi standards catalogue under the section entitled “international standards correspondence index”, or by using the “find” facility of the bsi standards electronic catalogue.a british standard does not purport to include all the necessary provisions of a contract. users of british standards are responsible for their correct application.compliance with a british standard does not of itself confer immunity from legal obligations.summary of pagesthis document comprises a front cover, an inside front cover, pages i and ii, the en title page, pages 2 to 8 and a back cover.this standard has been updated (see copyright date) and may have had amendments incorporated. this will be indicated in the amendment table on the inside front cover.licensed copy: institute of technology tallaght, institute of technology, mon jun 11 16:47:48 gmt+00:00 2007, uncontrolled copy, (c) bsiamd. no.datecommentsthis british standard, having been prepared under the direction of the electrotechnical sector committee, was published under the authorityof the standards committee and comes into effect on15 january 1999 bsi 06-1999isbn 0 580 30846 4amendments issued since publicationlicensed copy: institute of technology tallaght, institute of technology, mon jun 11 16:47:48 gmt+00:00 2007, uncontrolled copy, (c) bsibs en 61558-2-8:1999contentspage national forewordinside front cover foreword2text of en 61558-2-83 bsi 06-1999iiiblanklicensed copy: institute of technology tallaght, institute of technology, mon jun 11 16:47:48 gmt+00:00 2007, uncontrolled copy, (c) bsieuropean standard norme europenneeuropische normen 61558-2-8november 1998ics 29.180partly supersedes en 60742:1995english versionsafety of power transformers, power supply units and similarpart 2-8: particular requirements for bell and chime transformers(iec 61558-2-8:1998)scurit des transformateurs, blocs dalimentation et analoguespartie 2-8: rgles particulires pour les transformateurs pour sonneries(cei 61558-2-8:1998)sicherheit von tranformatoren, netzgerten und dergleichenteil 2-8: besondere anforderungen an kilngel- und lutewerkstransformatoren (iec 61558-2-8:1998)licensed copy: institute of technology tallaght, institute of technology, mon jun 11 16:47:48 gmt+00:00 2007, uncontrolled copy, (c) bsithis european standard was approved by cenelec on 1998-10-01. cenelec members are bound to comply with the cen/cenelec internal regulations which stipulate the conditions for giving this european standard the status of a national standard without any alteration.up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the central secretariat or to any cenelec member.this european standard exists in three official versions (english, french, german). a version in any other language made by translation under the responsibility of a cenelec member into its own language and notified to the central secretariat has the same status as the official versions.cenelec members are the national electrotechnical committees of austria, belgium, czech republic, denmark, finland, france, germany, greece, iceland, ireland, italy, luxembourg, netherlands, norway, portugal, spain, sweden, switzerland and united kingdom.ceneleceuropean committee for electrotechnical standardization comit europen de normalisation electrotechnique europisches komitee fr elektrotechnische normungcentral secretariat: rue de stassart 35, b-1050 brussels 1998 cenelec all rights of exploitation in any form and by any means reserved worldwide forcenelec members.ref. no. en 61558-2-8:1998 een 61558-2-8:19987 bsi 06-1999licensed copy: institute of technology tallaght, institute of technology, mon jun 11 16:47:48 gmt+00:00 2007, uncontrolled copy, (c) bsiforewordthe text of document 96/111/fdis, futureedition 1 of iec 61558-2-8, prepared by iec tc 96, small power transformers, reactors and powersupply units and special transformers, reactors andpower supply units: safety requirements, was submitted to the iec-cenelec parallel vote and was approved by cenelec asen 61558-2-8 on 1998-10-01.this part 2 is to be used in conjunction withen 61558-1. it was established on the basis of thefirst edition (1997) of that part 1.this part 2 supplements or modifies the corresponding clauses of en 61558-1, so as to convert it into the european standard “particular requirements for bell and chime transformers”.where a particular clause or subclause of part 1 is not mentioned in this part 2, that clause or subclause applies as far as is reasonable. where this part 2 states “addition”, “modification” or “replacement”, the relevant text of part 1 is to be adapted accordingly.this european standard supersedes section 3 of chapter iii of en 60742.subclauses, tables and figures which are additional to those in part 1 are numbered starting from 101.annexes which are additional to those in part 1 are lettered aa, bb, etc.the following dates were fixed: latest date by which the en has to be implemented at national level by publication of an identical national standard or byendorsement(dop) 1999-07-01 latest date by which the national standards conflicting with the enhave to be withdrawn(dow) 2001-07-01endorsement noticethe text of the international standardiec 61558-2-8:1998 was approved by cenelec as a european standard without any modification.contentspage1scope32normative references33definitions34general requirements35general notes on tests36ratings37classification38marking and other information49protection against accessibility to hazardous live parts410change of input voltage setting411output voltage and output current under load412no-load output voltage413short-circuit voltage414heating515short-circuit and overload protection516mechanical strength517protection against harmful ingress of dust, solid objects and moisture518insulation resistance and dielectric strength519construction520components621internal wiring622supply connections and other external flexible cords623terminals for external conductors624provision for protective earthing625screws and connections726creepage distances, clearances and distances through insulation727resistance to heat, abnormal heat, fire and tracking728resistance to rusting7foreword2annex c creepage distances, clearances and distances through insulationmaterial group ii8annex d creepage distances, clearances and distances through insulationmaterial group i8licensed copy: institute of technology tallaght, institute of technology, mon jun 11 16:47:48 gmt+00:00 2007, uncontrolled copy, (c) bsi1 scopereplacement:this international standard deals with all aspects of safety such as electrical, thermal and mechanical.this part 2-8 of iec 61558 applies to fixed, single-phase, air-cooled (natural or forced), indpendant or associated safety isolating transformers for bell and chimes, having a rated supply voltage not exceeding 250 v a.c., a rated frequency not exceeding 500 hz, a rated output not exceeding 100 va.the no-load output voltage shall notexceed 33 v a.c. or 46 v ripple free d.c. and therated output voltage shall not exceed 24 v a.c. or 33 v ripple free d.c.bell and chime transformers are generally intended to supply domestic sound signalling equipment and other similar devices where the load is applied for short periods of time.note 1 a partial load may be applied for illumination purposes.this standard applies to special safety isolating transformers (transformer for bell and chime) which are used where double or reinforced insulation between circuits is required by the installation rules or by the appliance specification.this standard is applicable to dry-type transformers. the windings may be encapsulated or non-encapsulated.note 2 attention is drawn to the fact that for transformers intended to be used in tropical countries special requirements may be necessary.this standard also applies to transformers incorporating electronic circuits. this standard does not apply to external circuits and their components intended to be connected to the input and output terminals or socket-outlets of the transformer.2 normative referencesthis clause of part 1 is applicable.3 definitionsthis clause of part 1 is applicable except as follows:addition:3.101bell and chime transformera single-phase safety isolating transformer specifically intended to supply domestic sound signalling equipment and other similar devices3.102normal operationconditions under which the transformer is operated in normal use (see clause 14)4 general requirementsthis clause of part 1 is applicable.5 general notes on teststhis clause of part 1 is applicable.6 ratingsthis clause of part 1 is applicable except as follows:addition:6.101 the rated output voltage shall not exceed 24 v a.c. or 33 v ripple free d.c.the preferred values of rated output voltage are: 8 v, 10 v, 12 v, 16 v, 24 v a.c.; 6 v, 12 v, 24 v d.c.6.102 the rated output shall not exceed 100 va. the preferred values of rated output are: 4 va, 8 va, 10 va, 12 va, 16 va, 18 va,20 va, 24 va, 36 va, 48 va.6.103 the rated frequency shall not exceed 500 hz.6.104 the rated supply voltage shall not exceed 250 v a.c.compliance with the requirementsof 6.101, 6.102, 6.103 and 6.104 is checked by inspection of the marking.7 classificationthis clause of part 1 is applicable except as follows:replacement:7.2 according to short-circuit protection or protection against abnormal use: inherently short-circuit proof transformers; non-inherently short-circuit proof transformers; fail-safe transformers.replacement:7.4 according to their mobility: fixed transformers.replacement:7.5 according to their time of operation: short-time operation; intermittent operation.note a partial load for illumination may be applied continuously.licensed copy: institute of technology tallaght, institute of technology, mon jun 11 16:47:48 gmt+00:00 2007, uncontrolled copy, (c) bsiaddition:7.101 according to the method of mounting: mounting in a distribution assembly; mounting in sound signalling devices(bells, chimes, buzzers, etc.); mounting on an outlet box or cabinet; flush mounted; surface mounted.8 marking and other informationthis clause of part 1 is applicable except as follows:addition:8.1 h) bell and chime transformers shall be marked with one of the graphical symbols shown in 8.11:8.11 addition:symbolexplanationnumber of symbol in iec 60417-2fail-safe bell andchime transformershort-circuit proof bell and chime transformer (inherently ornon-inherently)50139 protection against accessibility to hazardous live partsthis clause of part 1 is applicable except as follows:addition:9.101 protection against accidental contact with windings and hazardous live parts of the input circuit shall be ensured while connecting conductors to the output terminals.compliance is checked by inspection and by the application of the standard test finger shown in figure 2. it shall not be possible to touch windings or hazardous live parts of the input circuit with the test finger.10 change of input voltage settingthis clause of part 1 is applicable.11 output voltage and output current under loadthis clause of part 1 is applicable except as follows:modification:11.1a) replace 10 % by 15 % b) replace 10 % by 15 % c) replace 15 % by 20 % d) replace 5 % by 15 %compliance is checked by measuring the output voltage 2 min after the commencement of the test.12 no-load output voltagethis clause of part 1 is applicable except as follows:addition:12.101 the no-load output voltage shall not exceed 33 v a.c. or 46 v ripple free d.c. under any conditions even when independent output windings which are not intended to be connected in series, are connected in series.12.102 the difference between the no-load output voltage and the output voltage under load shall not be excessive.compliance with the requirements of 12.101and 12.102 is checked by measuring the no-load output voltage when the transformer, at ambient temperature, is connected to the rated supply voltage at rated frequency.the ratio between the no-load output voltage measured in this clause and the output voltage under load measured during the test of clause 11, expressed as a percentage of the latter voltage, shall not exceed 100 %note the ratio is defined as follows:13 short-circuit voltagethis clause of part 1 is not applicable.licensed copy: institute of technology tallaght, institute of technology, mon jun 11 16:47:48 gmt+00:00 2007, uncontrolled copy, (c) bsi14 heatingthis clause of part 1 is applicable except as follows:modification:14.2 temperatures are determined during a cyclic test of 20 cycles, each cycle consisting of 1 min operation with the simulated full load and 5 min operation with a load of 20 % of the simulatedfull load.the cyclic test is carried out at ambient temperature and a supply voltage at 1,06 times rated supply voltage. temperature rises are measured during the last cycle.the simulated full load is calculated as the impedance giving rated output at rated output voltage and for a.c. current at rated power factor when the transformer is supplied at rated supply voltage at ambiant temperature.the cyclic test is performed by switching between the impedance corresponding to the simulated full load and the impedance corresponding to 20 % of the simulated full load.replacement:table 1, note 33) the external enclosure of a bell and chime transformer only includes the parts accessible to the standard test finger when mounted in accordance with 14.2.addition:table 1, add “5)” to “supports” and add the following note 5:5) support includes any area of the black painted plywood support, but excludes any metal parts of the mounting system (rails, outlet boxes, etc.).15 short-circuit and overload protectionthis clause of part 1 applies except as follows:addition:15.101 the maximum short-circuit output current shall not exceed 10 a, measured 5 s after applying the short-circuit, the transformer being supplied with 1,06 times the rated supply voltage.16 mechanical strengththis clause of part 1 is applicable except as follows:modification:16.2 the impact hammer shall have an energy of (0,2 0,05) j.17 protection against harmful ingress of dust, solid objects and moisturethis clause of part 1 is applicable.18 insulation resistance and dielectric strengththis clause of part 1 is applicable.19 constructionthis clause of part 1 is applicable except as follows:replacement:19.1 the input and output circuits shall be electrically separated from each other and the construction shall be such that there is no possibility of any connection between these circuits, either directly or indirectly, via other metal parts.compliance is checked by inspection and measurements, taking clauses 18 and 26 into consid