1、 EIA STANDARD EIA/NARM STANDARD FOR DRY REED SWITCHES EIA-421-A (Revision of RS-421) MARCH 1983 EIA Standards Electronic Components Association NOTICE EIA Engineering Standards and Publications are designed to serve the public interest through eliminating misunderstandings between manufacturers and
2、purchasers, facilitating interchangeability and improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for his particular need. Existence of such Standards and Publications shall not in any respect preclude any member or nonmember of ECA
3、 from manufacturing or selling products not conforming to such Standards and Publications, nor shall the existence of such Standards and Publications preclude their voluntary use by those other than ECA members, whether the standard is to be used either domestically or internationally. Standards and
4、 Publications are adopted by EIA in accordance with the American National Standards Institute (ANSI) patent policy. By such action, EIA does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the Standard or Publication. This EIA Standard is
5、considered to have International Standardization implication, but the International Electro-technical Commission activity has not progressed to the point where a valid comparison between the EIA Standard and the IEC document can be made. This Standard does not purport to address all safety problems
6、associated with its use or all applicable regulatory requirements. It is the responsibility of the user of this Standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations before its use. (From Standards Proposal No. 1408 formulated unde
7、r the cognizance of the P-5.7 Working Group on Relays). Published by Electronic Components Association EIA Standards and Technology Department 2500 Wilson Boulevard, Suite 310 Arlington, VA 22201 Global Engineering Documents, USA and Canada (1-800-854-7179) International (303-397-7956) All rights re
8、served Printed in U.S.A. EIA 421-A 83 m 3234600 OOb3Y7 4 m 3 RS-421-A O Paraqraph EIA/NARM STANDARD FOR DRY REED SWITCHES TABLE OF CONTENTS 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0 17.0 18.0 19.0 20.0 21.0 22.0 23.0 24.0 25.0 26.0 27.0 O SCOPE APPLICABLE DOCUMENTS STAND
9、ARD REFERENCE CONDITIONS AND DEFINITIONS QUALITY CONTROL AND QUALITY ASSURANCE PROVISIONS VISUAL AND MECHANICAL INSPECTION OPERATIONAL PARAMETERS DIELECTRIC OPERATE, BOUNCE, RELEASE AND TRANSFER (SPDT) TIME INSULATION RESISTANCE INTERNAL MOISTURE BUMP VIBRATION SHOCK SEALS CONTACT STICKINESS CARRY C
10、URRENT CAPACITANCE LEAD FINISH THERMAL SHOCK SALT MIST TERMINAL STRENGTH CONTACT LIFE TESTING PHYSICAL DIMENSIONS PREPARATION FOR DELIVERY DETAIL SPECIFICATIONS STANDARD TEST COILS APPLICATION NOTES Page 1 2-3 3 - 10 4 - 11 11 - 13 13 - 16 17 - 18 18 - 22 22 - 23 23 24 24 - 25 25 - 26 26 - 28 28 - 3
11、0 31 33 34 34 34 34 - 35 36 - 42 43 - 44 44 45 - 47 48 - 49 50 - 52 -1 - - - - _I_ _ . . EIA 421-A 3 m 3234600 0068348 b m E RS-421-A Page 1 EIA/NARM STANDARD FOR DRY REED SWITCHES (From EIA Standards Proposal No. 1408, formulated under the cognizance of EIA P-5.7 Working Group on Relays.) 1.0 SCOPE
12、 This Standard applies to dry reed switches, magnetically actuated, with her- metically sealed contacts. The Standard provides the procedure to be used for inspecting, testing and rating various switch types as defined in the individual Detail Specifications. If the procedures are followed carefully
13、, the results should be uniform, correlatable test methods, standard acceptance and rejection criteria, and a means of comparing ratings of various manufacturers for similar types of switches. Switches conforming to this Standard are suitable for use in electrical and electronic equipment where appl
14、ication is within the stated limits of operation. This EIA Recommended Standard is considered to have international standardi- zation implications. IEC Standards, where applicable, have been included in this Standard to provide an international scope to products qualified under this Standard. An (IE
15、C) indicator precedes paragraphs or sections that are directly referenced to an IEC Standard. The test and measurement methods given in this Standard are not necessarily the only methods that can be used. However, the manufacturer should be capable of proving that the alternative methods which he ma
16、y use will give results equivalent to those obtained by the methods specified. Alternative methods shall not be used where methods are specifically designated to referee or reference methods. (IEC) It is the purpose of this Standard to provide realistic, objective testing means to define and determi
17、ne the quality of a given product. The intention is to provide the above without excessive testing costs. The Standard does not apply to mercury-wetted contacts even though the geometry may be similar to those of dry reed switches. L EIA 421-A 83 m 3234600 0068349 8 m t L l RS-4 21- A Page 2 2.0 APP
18、LICABLE DOCUMENTS The following documents form pat of this Specification to the extent noted herein. Military MIL-STD-105 - Sampling Procedures and Tables for Inspection by Attributes MIL-STD-202 - Test Methods far Electronic and Electrical Component Parts MIL-S-55433 2- Military Specification - Gen
19、eral Specification for Switch Capsules, Dry Reed Type Commerciql EIA RS-4074 Testing Procedures for Relays for Electrical and Electronic Equipment (July, 1978) Definitions and Terminology for Relays for Electronic Equipment Dry Reed Make Contact Units Basic Environmental Testing Procedures, Part 1:
20、General ANSI C83.16-1971, IEC 255-9 IEC 68-1 a IEC 68-2-1 Part 2: Tests, Tests.A: Cold IEC 68-2-2 IEC 68-2-3 at, Steady State IEC 68-2-4 Accelerated Damp Heat IEC 68-2-6 c: Vibration (sinusoidal) IEC 68-2-11 IEC 68-2-13 Test M; Low Air Pressure IEC 68-2-14 Testr N: Change of Temperature IEC 68-2-17
21、IEC 68-2-20 Tesi Q: Sealing Test T: Soldering IEC 68-2-ZOA First Supplement: Test Tb: Resistance to- Soldering Heat, Method 1 1- - 3 I . EIA 421-A 83 m 3234600 0068350 4 m RS-421-A Page 3 2.0 APPLICABLE DOCUMENTS (continued) Commerical IEC 68-2-21 Test U: Robustness of Terminations and Integral Moun
22、ting Devices IEC 68-2-27 Test Ea: Shock IEC 68-2-29 Test Eb: Bump IEC 255 Electrical Relays IEC 255-0d20 Contact Performance of EIectrical Relays IEC 255-5 Part 5: Insulation Tests for Electrical Relays IEC 317-1 Specifications for Particular Types of Winding Wires, Part 1: Enamelled Round Copper wi
23、th High Mechanical Properties 3.0 STANDARD REFERENCE CONDITIONS AND DEFINITIONS Unless otherwise specified, all tests shalt be carried out under standard conditions listed below. 3.1 3.2 3.3 3.4 Standard Temperature: 23OC +4OC If the measured parameter is dependent on temperature, the value shall be
24、 corrected by calculation to 20C. Relative Humidity 20 to 70% unless otherwise specified. Barometric Pressure 29.5 - + 1 inch Hg (749.3 - + 25.4 mm Hg) Definitions (Use of ANSI C83.16-1971 is recommended for definitions not listed below.) Ampere Turns (At) The product of the current passing through
25、an electromagnetic coil winding and the number of turns of -wire in that winding. Armature The moving part or parts of a reed switch. Back Contact Normally closed contact in a Form C switch (transfer switch). c EIA 421-A 3 m 3234600 00b351 b m I RS-421-A Page 4 3.4 Definitions (continued) Bias, Elec
26、trical An electrically produced force tending to move the armature towards a given position. Bias, Magnetic A steady magnetic field applied to the magnetic circuit of a switch to aid or impede operation of the armature. Bias, Mechanical A mechanical force tending to move the armature towards a given
27、 pqsition. Blades Sometimes used. to define the metal cantilever portion of the reed switch contained within the glass envelope, providing the combined function of the electrical and magnetic circuit. Bobbin Coil .form or spool on which a Coil is wound. Bounce, Contact Intermittent opening of closed
28、 contacts or closing of open contacts; bounce usually implies the motion resulting from contact impact. Bounce Time (IEC) The interval of time between Che instant of the first physical closing (or opening) and the instant of the final physical closing (or opening) of a reed contact unit. Br ea k-Be
29、f o r e-Ma ke Contact which interrupts one circuit before closing another circuit; Form C. Wewit of conta built up be tween between themc metallic protrusion or brjdge is es to cause an electrical path (2) A form of conta inductance circu and resolidifyin of bridge. the break of a low voltage, low a
30、ration, that results in melting e form of a metallic protrusion (3) Make-before-break action, as when a wiper touches two successive cont eously while moving from one to the other. Chatter, Contact The undesired inter contacts. It may o when the switch is osure of open contacts or opening of closed
31、the switch is operated tir released, or ernal shock or vibration. a EIA 421-A 83 m 3234600 0068352 8 m RC-421-A Page 5 3.4 Definitions (continued) Coil An assembly consisting of one or more windings on a common form. - Contact Circuit (IEC) The whole of the electrically conductive parts of a reed co
32、ntact unit which are intended to be connected in an external circuit (see Figure 1). _1 I k- Contact circuit .I i 1 I 4 c- FIGURE 1 CONTACT CIRCUIT Contact Circuit Resistance (IEC) The resistance of the contact circuit under sp ified conditi surement. Contact, Fixed Same as Fixed, Stationary. ns of
33、mea- Contact Blade See Blades. Contact Gap Same as Contact Separation. Contact Noise (IEC) The spurious peak-to-peak voltage which is generated across the reed contact unit terminations. Contact, Movable The member of a contact pair that is moved directly by the actuating system. Con tact Separation
34、 The distance between mating contacts when the contacts are open. Contact, C tationary The member of a contact combination that is not moved directly by the actuating system. Contacts The current-carrying parts of a switch that engage or disengage to open or close electrical circuits. 1 EIA 421-A 83
35、 = 3234600 00b8353 T RS-421-A Page 6 3.4 Definitions (continued) Dropout (DO) Value, Just (IEC) The value of the applied energizing quantity at which the operated teed contact unit just physically releases (see Figure 2). Time at Saturate Value O GYJ Time at Zero Ensrgitatlon Time FIGURE 2 (IEC) FUN
36、CTIONAL CHARACTERISTICS AND SEQUENCE OF TESTS Dropout Value (IEC) The stated limit of the applied energizing at which the operated reed -ontact unit shafI physically release (see Figure 2). Dropout Time See Release Time (Total). Duty Cycle The energized time compared to deenergized time in recurrent
37、 aperation such as: 1 second on, 2 seconds off. Dwell Form C contacts. The value of coil drive in ampere turns required to.open the normally closed circuit subtracted from the coil drive required to close the normally open contacts. Differential The difference, in ampere turns, between pickup and dr
38、opout values of a switch. PROBLEM HARD COPY EIA 421-A 83 m 3234600 O068354 L m RS-42 1- A Page 7 3.4 Definitions (continued) Differential, Close The characteristic of a switch whereby the pickup and dropout values are close to one another. Differential, Wide The characteristic of a switch whereby th
39、e pickup and dropout values differ widely from each other. Electrostatic Shield Grounded piece of thin metal surrounding the contacts to shield them from coil interference and noise. Failure- to-break (IEC) A fault condition of the reed contact unit, indicated by the contact circuit resistance of th
40、e unit failing to exceed a specified value, for a specified applied energization quantity within a specified period. Failure- t o-ma ke (IEC) A fault condition of the reed contact unit, indicated by the contact circuit resistance of the unit exceeding a specified value, foi a specified applied energ
41、ization quantity, within a specified period. Flux Field The magnetic lines of force produced by a coil or a permanent magnet, or both. Form “A“ Single pole, single throw (SPST) - normally open. that is open when the armature is in its unoperated position. A contact combination Form irBii Single pole
42、, single throw (SPST) - normally closed. A contact combination that is closed when the armature is in its unoperated position. Form “C“ Single pole, double throw (SPDT) - break-before-make. A contact combination in which the opening contact opens before the closing contact closes. Form ID“ Single po
43、le, double throw (SPDT) - make-before-break. A contact combination in which the -opening contact opens after the closing contact closes. Front Contacts Normally open contacts in SPDT Form “C“ (transfer switch). -.- - EIA 421-A 83 = 3234600 0068355 3 = RS-421-A Page 8 3.4 Definitions (continued) Gap,
44、 Maqnetic The distance between magnetic members within a reed switch; magnetic lines of force across this gap cause contact elosure. Hysteresis The amount of magnetization of a ferrous material, lags the magnetizing force due to molecular reluctance. Insulation Resistance The resistance of the glass
45、 body of the switch. Measured with an electrometer with the switch deenergized. Latching Contacts (Bistable) Contacts that lock in either position until reset. Normally Closed (NC) Contacts See Form B. Normally Open (NO) Contacts See Form A. Operate The condition attained by a switch when all contac
46、ts have functioned, Operate Time See Time, Operate. Operate Time (Total) Form A Contact - The total elapsed time from the instant power is applied to the energized quantity urd1 the contact has functioned and all contact bounce has ended, Form B Contacts - Thetotal elapsed time from the instant powe
47、r is removed from the energizing quantity until the contact has functioned and all. contact baunce has ended. * See Pickup Value- Qperate Value, Must (IEC) The stated limit of the applied energized quantity at which the reed contact unit shall physically -operate (ii-t ese charkwterlstias Eire not n
48、ormally tested for during lot inspection and are considered to be relatively uniform for any given switch type. .AAfthough not intentionally alterable -without modifying the basic des witch, there is a rangeaof variationthat does exist, and while t characteristics are normally specif ied by the manu
49、facturer Cas l.or maximum values), in some cases a value within the normal range ban be specified and supplied. ,- Y EIA 421-A 83 m 3234600 0068358 9 m RS-421-A Page 11 4.1 General (continued) This group of characteristics includes: Dielectric Breakdown, Operate Time, Bounce Time, Release Time, Transfer Time (SPDT switches), Insulation Resistance, Vibration Effect, Shock Effect, Seal, Contact Stickiness, Carry Current, Capacitance, Lead Finish, and Life Rating. The quality assurance program of suppliers to this specif ication must provide controls to ensure
