1、BRITISH STANDARD BS 3999-16: 1993 IEC 496:1975 (Including Amendment No.1:1977 and Amendment No.2:1992 Methods of Measuring the performance of household electrical appliances Part 16: Electric warming plates UDC 621.365: :64 644.19-41-83.083BS3999-16:1993 This British Standard, having been prepared u
2、nder the directionof the Light Electrical Engineering Standards Policy Committee, was published underthe authority of the Standards Board and comes into effect on 15 March 1993 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference LEL/59 Special announceme
3、nt in BSINews December 1992 ISBN 0 580 21992 5 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Light Electrical Engineering Standards Policy Committee (LEL/-) to Technical Committee LEL/59, upon which the following bodies were represente
4、d: Association of Manufacturers of Domestic Electrical Appliances Consumer Policy Committee of BSI Consumers Association Department of Trade and Industry (Electricity Division) Electricity Association Portable Electric Tool Manufacturers Association Rotating Electrical Machines Association (BEAMA Lt
5、d.) The following body was also represented in the drafting of the standard, through subcommittees and panels: Good Housekeeping Institute Amendments issued since publication Amd. No. Date CommentsBS3999-16:1993 BSI 10-1999 i Contents Page Committees responsible Inside front cover National foreword
6、ii Section 1. General 1 Scope 1 2 Object 1 Section 2. Definitions 3 Warming plate 1 Section 3. General notes on measurements 4 List of measurements 1 5 General conditions for measurements 1 Section 4. Measuring methods 6 Overall dimensions 1 7 Dimensions of warming surface 2 8 Length of flexible cor
7、d 2 9 Mass 2 10 Heating-up time and temperature 2 11 Ability to keep warm 2 12 Temperatures of warming surface in steady state 3 13 Temperature of supporting surface 3 Section 5. Functional provisions 14 Type of supply connection 3 15 Type of control 3 Appendix A Temperatures and differential of the
8、 warming surface 4 Appendix B Measuring device for measurement of ability to keep warm 5 Figure 1 4 Figure 2 5BS3999-16:1993 ii BSI 10-1999 National foreword This Part of BS 3999 has been prepared under the direction of the Light Electrical Engineering Standards Policy Committee. It is identical wit
9、h IEC 496:1975 Methods for measuring the performance of electric warming plates for household and similar purposes, including Amendment No. 1:1977 and Amendment No.2:1992, published by the International Electrotechnical Commission (IEC). Textual error. When adopting the text of the International Sta
10、ndard, the textual error given below was discovered. It has been marked in the text. Clause 8. Length of flexible cord, in line 2, “indicated in metres downwards to0.05m.” should read “indicated in metres, rounded downwards to the nearest0.05m.” A British Standard does not purport to include all the
11、 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 pages This document comprises a front cover, an inside front cover, pages i and ii,
12、pages1 to 5 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.BS3999-16:1993 BSI 10-1999 1 Section 1. General 1 Scope This specification applies to electric warming p
13、lates for household and similar purposes. Similar purposes denotes use in other than household areas, e.g. inns, coffee-houses, tea-rooms, small hotels, but only where the periods of use and the load are compatible with household purposes. 2 Object The purpose of this specification is to state and t
14、o define the principal performance characteristics of electric warming plates which are of interest to the user, and to describe the standard methods for measuring these characteristics. This specification is concerned neither with safety nor with performance requirements. Section 2. Definitions For
15、 the purpose of this specification, the following definitions apply: 3 Warming plate A horizontally-supported heated panel intended for maintaining crockery or food in containers, which may be an integral part of the appliance, at a temperature suitable for serving. 3.1 thermal storage warming plate
16、 a warming plate that may be charged with a certain amount of heat, either directly or indirectly and which can store it so that no further electrical supply is necessary for the period of use 3.2 warming plate sets an arrangement of more than one warming plate in a housing or in a stack 3.3 directl
17、y heated warming plate a warming plate with an electrical heating element built in NOTEDirectly heated warming plates may be with or without thermal storage. 3.4 indirectly heated warming plate a warming plate of the thermal storage type which is charged from an external heat source Section 3. Gener
18、al notes on measurements 4 List of measurements Overall dimensions (Clause6) Dimensions of warming surface (Clause7) Length of flexible cord (Clause8) Mass (Clause9). Heating-up time and temperature (Clause10). Ability to keep warm (Clause11). Temperature of warming surface in steady state (Clause12
19、). Temperature of supporting surface (Clause13). 5 General conditions for measurements Unless otherwise specified, the measurements are made under the following conditions: ambient temperature: 20 2 C for the measurements of Clauses10, 11, 12 and13; 20 5 C for the other measurements; input: rated in
20、put; testing room: substantially draught-free; placing of the appliance: on a dull black painted wooden support projecting beyond the appliance by at least50mm on all sides, at least30cm from walls. For the tests of Clauses12 and13, a support with thermocouples is used. This support consists of a20m
21、m thick dull black painted plywood board. At intervals of50mm, copper disks15mm in diameter and1mm thick are embedded so that they are flush with the surface. The outer side of the disks is blackened and on their inner side fine-wire thermocouples are fastened. Section 4. Measuring methods 6 Overall
22、 dimensions The overall dimensions length, width and height of the appliance are measured and indicated in millimetres. Handles are taken into account as well as any other projecting parts of the appliance, except the cord guard of a non-detachable flexible cord or an appliance connector of the cord
23、 set. In the case of warming plate sets, the dimensions of the complete arrangement are measured and indicated as well as the dimensions of the individual warming plates.BS3999-16:1993 2 BSI 10-1999 7 Dimensions of warming surface The shape of the surface on which the objects to be warmed are placed
24、 is described; for instance:rectangular, circular, oval. The dimensions of the surface, length and width or diameter are measured and indicated in millimetres. In the case of non-rectangular shapes, the size of the warming surface is also measured and indicated by its area in square centimetres. For
25、 warming plates where the warming surface is bordered by a higher rim, only the dimensions inside the rim and the height of the rim are measured and indicated. Where a warming plate has part of its area designed to operate at a higher temperature the dimensions are indicated in millimetres. 8 Length
26、 of flexible cord 1) The distance between the point of entry into the appliance and the plug, including any cord guard, is measured and indicated in metres rounded downwards to0.05m. 9 Mass The mass of the appliance, with its flexible cord if any, is measured and indicated in kilogrammes to the near
27、est0.1kg. For warming plate sets, the mass of the arrangement is measured and indicated as well as the mass of the individual warming plates. 10 Heating-up time and temperature The temperature is measured in the geometrical centre of the warming surface by a fine-wire thermocouple arranged so that g
28、ood thermal contact is ensured and its influence on the measuring results is as small as possible. In the case of an intended uneven temperature distribution, one thermocouple is connected to the centre of each section with different temperatures. The appliance, without any object placed on the warm
29、ing surface, is heated up from ambient temperature, any control being set to its maximum position or to the position for “warming” in the case of appropriate manufacturers instructions: until an indicator showing readiness for use operates, in the case of appliances having such a device (in the case
30、 of sets, on each individual warming plate); for the pre-heating period, if there are manufacturers instructions; to steady state, for all other designs. The time for heating-up is indicated in minutes, to the nearest full minute, together with the temperature, in degrees Celsius, reached in that ti
31、me. For warming plates without indicator or manufacturers instructions,90% of the steady-state temperature is taken; in the case of controlled appliances,90% of the average steady-state temperature is taken, and the time to reach this temperature is indicated in each case. For warming plate sets of
32、the housing type, the measurement is made on each individual warming plate; in the case of sets of the stack type, it is sufficient to measure the top and the bottom plates. NOTEOn metal, plastic and similar surfaces, the thermocouple may be fastened by means of a screw; on glass, vitreous enamel an
33、d the like, it may be glued. In order to exclude any restriction of the heat transfer to the upper warming plates of a stack type set, it may be necessary to lead the thermocouple through a hole, notch or the like, to the centre of the bottom plate. It is recommended to plot the temperature-rise dia
34、gram. 11 Ability to keep warm 11.1 Food in china containers A china bowl, as shown in Appendix B, is filled with0.5 l of boiling water. The water is stirred until it has cooled down to a temperature of80 C. The bowl is then closed with a rubber lid fastened by means of a metal cross, and a thermocou
35、ple is inserted in the bowl so that its junction is20mm from the bottom. The measuring device thus prepared is placed on the geometrical centre of the warming surface at the end of the heating-up time according to Clause10. Any area designed to operate at a higher temperature is separately tested by
36、 measurement of the temperature in the geometric centre of the area. Thermal storage warming plates are disconnected from the supply. After periods of30min and1h, the temperature of the water in the bowl is measured without stirring the water and these values are indicated indegreesCelsius. 11.2 Foo
37、d in special containers For warming plates with integral containers, the measurements of Sub-clause11.1 are made with these containers. The containers are filled with water to half their maximum capacity and closed in accordance with the manufacturers instructions. Holes of10.5mm in diameter are mad
38、e in the lid so that its total opening area is 1.6 0.2% of the water surface. 1) See national foreword for details of textual error.BS3999-16:1993 BSI 10-1999 3 12 Temperatures of warming surface in steady state The appliance under test, with any thermal control or switch set at its maximum position
39、, is heated up until it reaches steady state. The warming surface is divided into four equal sections, and in the geometrical centre of each the temperature is measured and indicated in degrees Celsius. NOTEAn example is given inAppendix A. For thermostatically-controlled warming plates, the tempera
40、ture cycling is recorded and the temperature differential is indicated together with the average steady-state temperature. NOTEThe measurement of Clause13 may be made at the same time. 13 Temperature of supporting surface For the measurement of Clause12, the warming plate under test is placed on the
41、 support with thermocouples, as described in Clause5, so that any external part of the appliance, for which high temperatures may be expected, can touch or may be as close as possible to the disks. The temperature of the disks is recorded and the maximum value is indicated in degrees Celsius. Sectio
42、n 5. Functional provisions 14 Type of supply connection It is determined and indicated whether the warming plate is provided with a non-detachable cord or with an appliance inlet and, in the latter case, whether it is delivered with or without cord set. 15 Type of control For controlled warming plat
43、es, the type of control is determined and indicated, and whether it is built into the appliance or forms part of the appliance coupler.BS3999-16:1993 4 BSI 10-1999 Appendix A Temperatures and differential of the warming surface Figure 1 BS3999-16:1993 BSI 10-1999 5 Appendix B Measuring device for me
44、asurement of ability to keep warm Figure 2 BS 3999-16: 1993 IEC496:1975 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the international lev
45、el. It is incorporated by Royal Charter. Revisions BritishStandards are updated by amendment or revision. Users of BritishStandards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be gra
46、teful if anyone finding an inaccuracy or ambiguity while using this BritishStandard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover. Tel:02089969000. Fax:02089967400. BSI offers members an individual updating service cal
47、led PLUS which ensures that subscribers automatically receive the latest editions of standards. Buying standards Orders for all BSI, international and foreign standards publications should be addressed to Customer Services. Tel:02089969001. Fax:02089967001. In response to orders for international st
48、andards, it is BSI policy to supply the BSI implementation of those that have been published as BritishStandards, unless otherwise requested. Information on standards BSI provides a wide range of information on national, European and international standards through its Library and its Technical Help
49、 to Exporters Service. Various BSI electronic information services are also available which give details on all its products and services. Contact the Information Centre. Tel:02089967111. Fax:02089967048. Subscribing members of BSI are kept up to date with standards developments and receive substantial discounts on the purchase price of standards. For details of these and other benefits contact Membership Administration. Tel:02089967002. Fax:02089967001. Copyright Copyright subsists in all BSI publications. BSI also holds the copyright, in the
