IEC 60617 - Graphical Symbols for Diagrams

CHANGE REQUEST
Request identity number:	C00104
Applies to:	S01462
Type of request:	Technical modification
Request status level:	Resolved
Proposal:	Introduce a symbol for "Mirror contact".
Reason:	The CZ NC made the Secretariat aware of the fact that a symbol for mirror contact is specified in IEC 60947-4-1: 2002 (consolidated with Am. 1) Annex F. The need to introduce the symbol has been confirmed by the Secretariat of SC17B. This symbol is simultaneously processed for introduction in IEC 60417. -------------------------------------------------- The definition of mirror contact is provided in the actual publication (annex F): mirror contact normally closed auxiliary contact which cannot be in closed position simultaneously with the normally open main contact under conditions defined in clause F.7 NOTE - One contactor may have more than one mirror contact. --------------------------------------------------
Requested by:	Secretary of TC3 per-ake.svensson@se.abb.com IT
General comments:
Comments at evaluation:	Submitted for evaluation 2003-02-18. Comment from the Secretary of SC17B after review of the initial design 2003-02-18. Thank you for your message. I don't have any comment on documents you have prepared. Thank you very much for your help. Yours sincerely, Marcel Delaplace Secretary IEC SC17B -------------------------------------------------- DE(RESC): We have carefully studied annex F of IEC 60947-4-1 and most carefully the definition of "mirror contact" but we still are looking for more information. We understand that, if main contacts are open and the device has NO and NC auxiliary contacts,that in any case there are "mirrors" of the main contacts. If a simultaneously operation with the main contacts should be prevented, than e.g symbol S00154 may be used. Has anybody got more details about the CR? AT(WGAS): Yes to the proposal -------------------------------------------------- Comment by the Secretary 2003-06-03: In view of the above some questions were forwarded to SC17B, on which the following replies were given: Dear Mr Svensson, As promised in my e-mail dated 2003-05-23, please find hereafter comments of Mr Michel Bret, onvenor of the WG in charge of IEC 60947-4-1. 1 - Q: Regarding the comment from DE in S01462 : What exactly differentiates a mirror contact form any other auxilliary contact that follows a main contact? A: A mirror contact reflects the state of main contacts even if the position of the main contact is not a "normal" position which can be the case under welded situation (an ordinary auxiliary contact indicates the state of the main contacts in normal positions ON and OFF but the indication under welded conditions is not defined and, consequently, not reliable which is not acceptable for some applications e.g. safety applications). 2 - Q: Is this property indicated in a clear enough way? "Dots" have often been use to merely indicate "this is something special" but without saying what. If that method is applied too much there are many dots but no clear overall meaning. A: This symbol is now used for several years and seems well accepted in the field; moreover, the big dot of the diagram is intended to represent the glass of a mirror and the contact line the handle of the mirror consequently the diagram is felt in good accordance with the word "mirror". 3 - Q: "positive operation". Is the proposed symbol some kind of parallel to this? Positive operation as a concept might by some be only related to mechanical forcing. A: A positive operation applies to devices provided with an activating device (e.g. an handle) which is not the case here. 4 - Q: Is the proposed symbol to be used also for static switches? A: The answer is no. We hope these explanations will help the understanding of our proposal and, consequently, to reach a positive vote as we would be very pleased to have this symbol accepted within IEC 60417 and IEC 60617 standards. Yours sincerely, Marcel Delaplace Secretary IEC SC17B -------------------------------------------------- Based on the answer a more clear explanation of the mirror function will be added to the symbol and the "dot" slightly enlarged. The symbol will then be submitted for validation.
Comments at validation:	Submitted for validation 2003-06-11, with a closing date of 2003-08-22, in order to synchronize with the processing of the corresponding symbol in IEC60417. DE(RESC): Refering to the "Remarks" one question: is this special kind of contact defined as NC- Type only, or might it also be a NO-Type? JP(HIKE): See also comments on C00030 of IEC 60417. AT(WGAS): The symbol S01462 is a normal contact with a special contact drive. Is it possible to show this function with the valid contact drive symbols ?
Voting at validation:	DE(RESC): Yes to the proposal AT(WGAS): Yes to symbol S01462.See also comments. JP(HIKE): Yes to the graphical symbol S01462 CN(GUTI): Yes to symbol S01462. IT(DISE): Yes to the graphical symbol S01462 NO(ES): Yes to the proposal DK(KATH): Yes to the proposal -------------------------------------------------- Conclusion by the Secretary 2003-08-27: The proposal has been approved and the symbol will be released. The comments above will be forwarded to the Secretary of SC17B for clarification, to see if the Remark can be further improved. -------------------------------------------------- Comment by the Secretary 2003-09-04: The Secretary of SC17B has provided the following answer: ---------------------------- Dear Mr. Svensson, Following a discussion I have had with Mr. Bret, Convenor of the WG in charge of IEC 60947-4-1, please find hereafter our answers to questions arisen during the validation procedure. 1 - Comments on IEC 60417: 1.1 - CZ comment: For the clarity of the matter, it is useful to keep in the definition an example of abnormal conditions like "welding of the main contact". Therefore we suggest not to change the existing text of the definition. We are not sure that abbreviations NO and NC are standardized for auxiliary contacts and for main contacts, if yes these could be added. The note "One contactor may have more than one mirror contact." could be added but we think that the general definition is sufficient and the note is not appropriate in an horizontal standard as only a contactor is mentioned. 1.2 - NL comment: For more information, Annex F of IEC 60947-4-1 should be considered as it gives all specific requirements. 2 - Comments on IEC 60617: 2.1 - DE comment: This special kind of contact is defined only as NC contact. 2.2 - AT comment: The risk is to increase the complexity of the symbol and therefore to decrease the clarity. However the AT suggestion could be introduced in an application guide. We hope these answers will improve the understanding of the matter. Thank you again for your kind co-operation. Best regards, Marcel Delaplace Secretary IEC SC17B ---------------------------- The Remark will therefore not be modified.
Requested on:	2003-02-13
Evaluated on:	2003-06-03
Resolved on:	2003-08-27
Withdrawn on:
Evaluation closing on:	2003-04-25
Validation closing on:	2003-08-22