1、_ SAE Technical Standards Board Rules provide WKDW7KLVUHSRUWLVSXEOLVKHGE6$(WRDGYDQFHWKHVWDWHRIWHF KQLFDODQGHQJLQHHULQJVFLHQFHV7KHXVHRIWKLVUHSRUWLV entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrRPLVWKHVROHUHVSRQVLELO
2、LWRIWKHXVHU SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2016 SAE International All rights reserved. No part of this publication may be reproduced, store
3、d in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-4970 (outside USA) Fax: 724-776-0790 E
4、mail: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/standards.sae.org/AS4914D AEROSPACE STANDARD AS4914 REV. D Issued 1978-01 Revised 2016-12 Superseding AS4914C Aircraft Fluorescent Lighting Ballast/
5、Fixture Safety Standard RATIONALE The document needs to be updated to incorporate references to new CFR Part 25 regulations related to ballasts. 1. SCOPE The purpose of this standard is to recommend minimum performance requirements to assist the specification writer in establishing a failsafe airpla
6、ne interior Fluorescent light assembly design. This standard relates to the design of lamp ballasts, lampholders, fixtures, and installation of the same. 2. APPLICABLE DOCUMENTS The following publications form a part of this document to the extent specified herein. The latest issue of SAE publicatio
7、ns shall apply. The applicable issue of other publications shall be the issue in effect on the date of the purchase order. In the event of conflict between the text of this document and references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes
8、 applicable laws and regulations unless a specific exemption has been obtained. 2.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or +1 724-776-4970 (outside USA), www.sae.org. ARP4761 Guidelines and Me
9、thods for Conducting the Safety Assessment Process on Civil Airborne Systems and Equipment 2.2 ASTM Publications Available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org. ASTM D495-48T Standard Test Method for High-Vol
10、tage, Low-Current Dry Arc Resistance of Solid Electrical Insulation SAE INTERNATIONAL AS4914D Page 2 of 10 2.3 FAA Publications Available from Federal Aviation Administration, 800 Independence Avenue, SW, Washington, DC 20591, Tel: 866-835-5322, www.faa.gov. 14 CFR Part 25 Airworthiness Standards: T
11、ransport Category Airplanes, Code of Federal Regulations AC 25-10 FAA Advisory Circular, Guidance for Installation of Miscellaneous, Non- Required Electrical Equipment AC 25.1309-1A FAA Advisory Circular, System, Design and Analysis AC 25.1365-1 Electrical appliances, motors, and transformers 2.4 NE
12、MA Publications Available from National Electrical Manufacturers Association, 1300 North 17th Street, Suite 900, Arlington, VA 22209, Tel: 703-841-3200, www.nema.org. NEMA_MW-1000 Magnetic Wire Standards 2.5 RTCA Publications Available from RTCA, Inc., 1150 18th Street, NW, Suite 910, Washington, DC
13、 20036, Tel: 202-833-9339, www.rtca.org. RTCA/DO-160 Environmental Conditions and Test Procedures for Airborne Equipment 2.6 U.S. Government Publications Copies of these documents are available online at http:/quicksearch.dla.mil. MIL-HDBK-454 Department of Defense Handbook, General Guidelines for E
14、lectronic Equipment. MIL-STD-1547 Department of Defense Handbook, Electronic Parts, Materials, and Processes for Space Vehicles MIL-STD-889 Military Standards - Dissimilar Metals MIL-PRF-27 Military Specifications for Transformers and inductors (Audio, Power and High Power Pulse), General Specificat
15、ion for NAVSO P-3641 More Power for the Dollar (This document is available at the following website http:/www.bmpcoe.org/library/books/navso%20p-3641a/index.html) 3. GENERAL DESIGN REQUIREMENTS Equipment supplied under the requirements of this document shall be designed to the following standards an
16、d provide the proper performance operation under the environmental performance levels specified. Requirements include applicable Part 25 Federal Aviation Regulations (FARs). Also as a guide, Advisory Circulars AC 25-10 and AC 25.1309-1A can be used. The design/construction of all equipment shall inc
17、orporate features which allow the equipment to be operated safely. Testing shall be conducted to verify the applicable design standards defined in this document. SAE INTERNATIONAL AS4914D Page 3 of 10 3.1 Materials and Finishes Materials and finishes used in the construction of the ballast/fixture s
18、hall be capable of withstanding the airplane environments as specified by RTCA/DO-160 (see Section 4) such as Temperature and Altitude, Temperature Variation, Humidity, Operational and Crash Safety Shocks, Vibration, Fungus Resistance, Sand and Dust, Power Input, Voltage Spike, Audio Frequency Condu
19、cted Susceptibility, Induced Signal Susceptibility, Radio Frequency Susceptibility, Radiated and Conducted Emission of Radio Frequency Energy, and Electrostatic Discharge. a. Metals: All metals shall be of the corrosion resistant type unless suitably protected to resist corrosion during normal servi
20、ce life. Guidance regarding metals in contact with each other shall be selected and protected as defined in MIL-STD-889. b. Nonmetallic Materials: Materials which are nutrients for fungi shall not be used. c. Flammable Materials: All nonmetallic/metallic composite materials shall meet Part 25.853 re
21、quirements. d. Electrical wire shall meet the applicable sections of Part 25.869(a)(4), 25.1703 thru 25.1721 and 25.1729 for Electronic Wiring Interconnection Systems (EWIS). 3.2 Lampholders a. The arc resistance time of lampholder insulating materials shall exceed 125 seconds, when tested per the A
22、rc Resistance Test, ASTM designation D495-48T, Standard Test Method for High-Voltage Low Current Arc Resistance of Electrical Insulation. b. The lampholders shall be capable of retaining the fluorescent lamp and permit satisfactory lamp operation throughout the specified airplane environment. c. Gol
23、d plated lamp contacts are recommended. d. Moisture resistant lampholders shall be specified or the fixture design shall provide protection for the lampholder from condensation and moisture accumulation. In-service history has shown that either moisture or condensation dripping onto lampholders may
24、result in an arcing condition during flight which impacts crew workload, operation and could possibly even result in an air turn-back. e. Lampholders should mechanically lock or have a means to secure the lamp and lamp contacts into position. The goal is to prevent misinstallation of the fluorescent
25、 lamp which could result in an arcing condition that may damage the light assembly. f. Electrical contact: Electrical contact resistance between the lamp contacts and lampholder contacts (pin or sockets) should be minimized by maximizing surface area and providing appropriate pressure. Lampholders t
26、hat only depend on spring pressure tend to arc under intermittent contact during vibration. Contacts should engage at least three quarters of the diameter of the lamp contact. g. The ballast shall not sustain damage if lamps are removed or installed with power applied. h. It is recommended that the
27、Fluorescent Lighting Ballast/fixture design include measures that will prevent the following known lampholder failure modes: 1. Lamp Mis-Installation - If the lamps are not fully seated and retained in the lamp holder, an intermittent connection can develop. The resulting electrical arc and associat
28、ed heating can severely damage the lampholder. 2. Use of Broken Lampholders - As with a mis-installed lamp, unsecured lamp contacts can result in electrical arcing and lampholder damage. SAE INTERNATIONAL AS4914D Page 4 of 10 3. Ground Fault - This fault occurs on lampholders where a (conductive) la
29、mpholder fastener is attached to the airframe and is relatively close to the lampholder contact. Over time, a conductive path develops between the contact and fastener across the lampholder body. Once initiated, the conductive path increases until a short circuit occurs. 4. End of Life lamps - As a
30、fluorescent lamp ages, the cathode filaments deteriorate, ultimately failing as an open circuit. The lamp will continue to operate with the failed filament. However, the remaining elements will reach high temperatures. The heat is transferred to the lamp base which in turn damages the light assembly
31、. A periodic check should be recommended by the manufacturer to detect discoloration and prevent light assembly damage. It is highly recommended that a ballast with the ability to detect fluorescent lamp failures be used in all aircraft interior light assemblies. This will help alleviate failures as
32、sociated with the End of Life and mis-installation of fluorescent lamps. 5. Overheating Conditions - Discoloring marks and lampholder melting may occur as a result of a lamp reaching its end of life while the ballast attempts to illuminate the lamp. Light assembly damage may occur as a result of usi
33、ng a non-compatible ballast. 3.3 Ballast/Fixture When operating in an ambient of 77 F (25 C), the exposed surface shall not exceed 160 F (71 C) under any conditions of normal, abnormal, overload operations or failure. All materials used shall be self-extinguishing per Part 25.853. The ballast shall
34、be designed in such a manner to be smoke and fume free when subjected to the conditions called out in RTCA DO-160 as specified in Paragraph 3.1. Electrical wire shall meet Part 25.869 and applicable sections of 25.1703 thru 25.1721 and 25.1729 for Electronic Wiring Interconnection Systems (EWIS). Th
35、e ballast should be designed to have the capability of containing smoke, flame, and arcing when subjected to the test conditions called out in RTCA DO-160 as specified in Section 4 of this document. Ballasts (including those that allow some ventilation) shall: a. be metallic to provide a barrier for
36、 flames to not propagate. b. have protection features that will not allow hazardous quantities of toxics or smoke to be emitted (see 3.7 and 3.9). c. have circuit boards that contain fire retardants per Part 25.853 so as not to propagate flame when circuitry has failed. 3.4 Schematic A schematic sha
37、ll be affixed to the equipment. The schematic shall clearly show the electrical connections such as input voltage, frequency, dimmer control and lamp load (type or power) and ground plane spacing dimension. 3.5 Ground Plane If the ballast or integrated light fixture and ballast design approach requi
38、res a minimum ground plane spacing, either the airplane lamp installation or the integrated light fixture itself shall provide the proper ground plane spacing. 3.6 Connector/Contacts Connectors with gold plated or Berryllium-Copper (BeCu) contacts are recommended for the power input and product-to-p
39、roduct electrical connections. If it is probable that an incorrect connection between various light assemblies or ballasts could cause a catastrophic failure, keyed connectors, mounting hole or foot print variations or other mechanical means shall be used to prevent incorrect connections. SAE INTERN
40、ATIONAL AS4914D Page 5 of 10 Plastic shell connectors are preferable to metal shell connectors or terminal boards (open terminals). Ballasts using open terminals are not preferred due to their lack of protection and their susceptibility for collecting dust. If open terminals are to be used, the term
41、inals should be covered or sealed after making the connections. 7KHFRQQHFWRUVPRLVWXUHUHVLVWDQFHOHYHOFDWHJRUVKDOOEHFRQVLVWHQWZLWKWKHODPSKROGHUO Lght fixture and ballast design, and the environmental requirements listed in Section 4. Arcing of contacts should not occur because of vibration. 3.7 Therma
42、l Protection The equipment shall be protected against overheating by thermal protective devices. The rated trip temperature of these thermal protective devices must be lower than that of the rated temperature of the material that is being protected. It is recommended that verification tests be condu
43、cted to ensure the effectiveness of these thermal protective devices when tested in their actual product locations (4.1.1). 3.8 Electrical Grounding and Bonding The equipment shall provide a grounding system capability that is compatible with the grounding within the aircraft and all other equipment
44、 which is used with or which interfaces with the equipment. 3.9 Electrical Protection The input power circuit of the electrical equipment shall contain a fuse or circuit breaker with a current rating of at least 50% RYHUWKHSURGXFWVPDLPXPLQSXWFXUUHQWXQGHUZRUVWFDVHYROWDJ e and environment conditions (
45、see Section 4). The fuse part number shall be marked adjacent to the fuse on external replaceable fuses. External replaceable fuses are optional. Where possible, output short circuit protection is desirable to prevent smoke or fire. It is recommended that ballast designs contain circuitry that provi
46、des overvoltage protection and detects electrical arcing, ground faults, open filaments, and lamp open circuits to prevent overheating and improve safety. 3.10 Standard Parts Guidance on the selection of electrical/electronic components can be found in MIL-HDBK-454. Particular consideration shall EH
47、JLYHQWRWKHSDUWVHQYLURQPHQWDOOLPLWVHOHFWULFDOFKDUDFWHULVWLFVDQG OLPLWVSRZHUUDWLQJVDQGPDWHULDOVXVHG$OOSD rts shall be suitably derated to ensure safety. Recommended derating guidelines can be found in NAVSO P-3641 or in MIL-STD-1547. Note that the use of high voltage capacitors and inductors/transformers in the ballast, when they fail short, can cause catastrophic failure to the ballast. Circuit designs should therefore have provisions to mitigate such potential failures. Additionally, there
