1、AEROSPACESTANDARDTACHOMETER INSTRUMENTS(Indicator and Generator)Issued 1959-02Revised 1996-09REV. AS432 BFOREWORDChanges in the revision are format/editorial only.1. SCOPE:This SAE Aerospace Standard (AS) covers tachometer instruments (RPM indicator, 0-110 percentRPM and 0-120 percent RPM indicators
2、 and generator) for remote indication of engine speed.1.1 Purpose:This AS establishes the essential minimum safe performance standards for TachometerInstruments primarily for use on turbine-powered subsonic transport aircraft, the operation ofwhich may subject the instruments to the environmental co
3、nditions specified in Section 3.3.2. APPLICABLE DOCUMENTS:The following publications form a part of this document to the extent specified herein. The latestissue of SAE publications shall apply. The applicable issue of other publications shall be the issuein effect on the date of the purchase order.
4、 In the event of conflict between the text of thisdocument and references cited herein, the text of this document takes precedence. Nothing in thisdocument, however, supersedes applicable laws and regulations unless a specific exemption hasbeen obtained.2.1 SAE Publications:Available from SAE, 400 C
5、ommonwealth Drive, Warrendale, PA 15096-0001.ARP582 Lighting, Integral for Aircraft Instruments, Criteria for DesignSAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely volunt
6、ary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your wri
7、tten comments and suggestions. Copyright 2008 SAE International All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permi
8、ssion of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: 724-776-4970 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.orgReaffirmed 2008-02SAE AS432 Revision B- 2 -2.2 NACA Publications:Available from NTIS, Springfield, VA 2
9、2161NACA Report 12353. GENERAL REQUIREMENTS:3.1 Material and Workmanship:3.1.1 Materials: Materials shall be of a quality which experience and/or tests have demonstrated tobe suitable and dependable for use in aircraft instruments.3.1.2 Workmanship: Workmanship shall be consistent with high-grade ai
10、rcraft instrumentmanufacturing practice.3.2 Identification:The following information shall be legibly and permanently marked on the instrument ornameplate attached thereto:a. Name of instrumentb. SAE AS432Bc. Manufacturers part numberd. Manufacturers serial number or date of manufacturee. Manufactur
11、ers name and/or trademarkf. Rangeg. Explosion category3.3 Environmental Conditions:The following conditions have been established as minimum design requirements. Tests shall beconducted as specified in Sections 5, 6, and 7.3.3.1 Temperature: When installed in accordance with the instrument manufactu
12、rers instructions,the instrument shall function over the range of ambient temperature shown in Column A belowand shall not be adversely affected by exposure to the range of temperature shown in ColumnB below:TABLE 1Instrument Location A BPower Plant Accessory Compartment -30 to 150 C -65 to 150 CPre
13、ssurized Areas -30 to 70 C -65 to 70 CNon-Pressurized or External Areas -55 to 70 C -65 to 70 CSAE AS432 Revision B- 3 -3.3.2 Altitude: When installed in accordance with the instrument manufacturers instructions, theinstrument shall function from sea level up to the altitudes and temperatures listed
14、 below. Altitude pressure values are per NACA Report 1235. The instrument shall not be adverselyaffected following exposure to extremes in ambient pressure of 50 and 3 inches of mercuryabsolute respectively.TABLE 2Instrument Location Alt. Feet Temp.Power Plant Accessory Compartment 60,000 80 CPressu
15、rized Areas 15,000 50 CNon-Pressurized or External Areas 60,000 40 C3.3.3 Vibration: When installed in accordance with the instrument manufacturers instructions, theinstrument shall function and shall not be adversely affected when subjected to vibrations of thefollowing characteristics.TABLE 3Max.I
16、nstrument Location Cycles Double Max. PeakOn Airframe Per Second Amplitude Accel.Nacelle and Nacelle Mounts,Wings, Empennage and Wheel Wells 5-1000 0.036 inch 10 gFuselageForward of Spar Area 5-500 0.036 inch 2 gCenter of Spar Area 5-1000 0.036 inch 4 gAft of Spar Area 5-500 0.036 inch 7 g500-1000 -
17、 5 gVibration Isolated Rack 5-1000 0.030 inch 1.0 gFlight Deck Area 5-30 0.020 inch -30-1000 - 0.25 g3.3.4 Humidity: The instrument shall function and shall not be adversely affected following exposureto any relative humidity in the range from 0 to 95% at any temperature up to 70 C.SAE AS432 Revisio
18、n B- 4 -3.4 Explosion Category:The instrument component, when intended for installation either in uninhabited areas of non-pressurized aircraft or in non-pressurized areas of pressurized aircraft, shall not cause anexplosion when operated in an explosive atmosphere. The component shall meet therequi
19、rements applicable to the explosion category below. Specifically, any instrument componentwhich can be an ignition source and is intended for installation in an area which combustible fluidor vapor may result from abnormal conditions, e.g., fuel line leakage, shall meet the requirementsof Category I
20、. If the intended location is an area where combustible fluid or vapor can occurduring normal operation, e.g., fuel tank, the instrument component shall meet the requirements ofCategory II, listed below:TABLE 4Category Definition RequirementsI Explosion-proofed; case not Paragraph 7.3.1designed to p
21、reclude flameor explosion propagation.II Explosion-proofed; case designed Paragraph 7.3.2to preclude flame or explosionpropagation.III Hermetically sealed. Paragraph 6.5IV Instrument not capable of Shall not be cap-causing an explosion. able of producinga capacitive orinductive sparkof more than 0.2
22、millijoules ofenergy or a con-tact spark ofmore than 4.0millijoules ofenergy.3.5 Fire Hazard:The instrument shall be so designed to safeguard against hazards to the aircraft in the event ofmalfunction or failure, and the maximum operating temperature of surfaces of any instrumentcomponent contacted
23、by combustible fuel or vapor shall not exceed 200 C due to self-heating.SAE AS432 Revision B- 5 -3.6 Radio Interference:The instrument shall not be the source of objectionable interference, under operating conditionsat any frequencies used on the aircraft, either by radiation or feedback, in electro
24、nic equipmentinstalled in the same aircraft as the instrument.3.7 Magnetic Effect:The magnetic effect of the instrument shall not adversely affect the performance of otherinstruments installed in the same aircraft.3.8 Decompression:When installed in accordance with the instrument manufacturers instr
25、uctions, the indicator shallfunction and not be adversely affected following exposure to a pressure decrease from22 to 2 inches of mercury in 2 seconds.4. DETAIL REQUIREMENTS:4.1 Indicator:4.1.1 Indicating Method: Engine speed shall be indicated in RPM or in percent RPM by means of oneor more pointe
26、rs, dials, tapes, drums, or other types of moving elements. Relative motion ofthe index with respect to the scale (either the index or the scale may be the moving element)shall be clockwise or “up” or to the right for increasing RPM or percent RPM.4.1.2 Display Markings:4.1.2.1 Finish: Unless otherw
27、ise specified by the user, matte white material shall be applied to allgraduations, numerals and indication means.Non-functional surfaces and markings shall be durable dull black.4.1.2.2 Graduations: The graduations shall be arranged to provide a maximum of readabilityconsistent with the accuracy of
28、 the instrument.4.1.2.3 Numerals: The display shall include sufficient numerals to permit quick and positiveidentification of each graduation.Numerals shall distinctly indicate the graduation to which each applies.4.1.2.4 Instrument Title: The instrument title, when used, shall be of the same approx
29、imate size, butno larger than the numerals. The title may be of the same finish as the numerals. The unitsof measure (RPM or percent RPM) shall appear on the dial in lettering noticeably smaller thaneither the numerals or title.SAE AS432 Revision B- 6 -4.1.2.5 Visibility: The indicating means and al
30、l markings shall be visible from any point within thefrustum of a cone the side of which makes an angle of at least 30 degrees with theperpendicular to the dial and the small diameter of which is the aperture of the instrumentcase. The distance between the dial and the cover glass shall be a practic
31、al minimum.4.1.3 Hermetic Sealing: When hermetically sealed, the case shall be filled with an inert gas, free ofdust particles, and sufficiently dry so that fogging of the indicator glass does not occur duringthe low temperature or fogging tests of this Aerospace Standard.4.1.4 Integral Lighting: In
32、tegral lighting, if provided, shall be in accordance with ARP582 “Lighting,Integral for Aircraft Instruments, Criteria for Design”.4.2 Generator:The generator shall be designed to operate in either direction of rotation and in any position.5. TEST CONDITIONS:5.1 Atmospheric Conditions:Unless otherwi
33、se specified herein, all tests required by this Aerospace Standard shall be made atan atmospheric pressure of approximately 29.92 inches of Mercury, an ambient temperature ofapproximately 25 C and relative humidity of not greater than 85%. When tests are conductedwith the atmospheric pressure or the
34、 temperature substantially different from these values,allowance shall be made for the variation from the specified conditions.5.2 Vibration (to minimize friction):Unless otherwise specified herein, all tests for performance may be conducted with theinstrument subjected to a vibration of 0.001 inch
35、double amplitude maximum at a frequency of10 to 60 cycles per second. The term double amplitude, as used herein, indicates the totaldisplacement from positive maximum to negative maximum.5.3 Vibration Equipment:Vibration equipment shall be such as to allow vibration to be applied along each of three
36、 mutuallyperpendicular axes of the instrument at frequencies and amplitudes consistent with therequirements of paragraph 3.3.3.5.4 Position:Unless otherwise specified herein, all tests shall be conducted with the instrument in its normaloperating position.SAE AS432 Revision B- 7 -5.5 RPM vs. Percent
37、 RPM Requirements:For instruments with markings in RPM instead of percent RPM, all references herein to percentRPM or % RPM shall apply and shall be interpreted to mean the RPM value equivalent to thestated percent of the indicated RPM corresponding to 4200 RPM generator drive shaft speed.6. INDIVID
38、UAL PERFORMANCE REQUIREMENTS:All instruments shall be subjected to tests by the instrument manufacturer to demonstrate specificcompliance with this Aerospace Standard, including the following requirements where applicable.6.1 Scale Error at Room Temperature:The tachometer indicator shall be connecte
39、d to a generator that meets the requirements ofParagraph 6.6 and the generator operated at the shaft speeds listed in either Table 5 or Table 6.The test shall be made either by driving the generator at a speed to produce the specifiedindicator readings and reading the speed of the generator, or by d
40、riving the generator at thespecified speeds and reading the indicator. The test shall be made with speeds increasing andthe speed shall be brought up to, but shall not exceed the speed specified to give the desiredreading. The scale error at any speed shall not exceed the values specified in the Tab
41、le.When the speed is held constant at any point on the scale, the pointer shall not oscillate over arange greater than 0.5% from 5 to 20% RPM and 0.3% from 20% RPM to full scale.6.2 Friction Error:The indicator shall be set at the 5, 20, 40, 70, 85 and 100 percent graduations, or at generatorspeeds
42、of 200, 800, 1600, 3200, 3600 and 4200 RPM, whichever is more convenient. After eachsetting, the indicator shall be tapped and the change in indications noted. The change shall notexceed 2% at the 5% graduation, 1% at the 20% graduation, and .75% at the 40, 70, 85, and100% graduations.6.3 Position E
43、rror:The indicator shall be operated at 100% with the instrument in its normal operating position. Readings obtained with the indicator tilted 45 degrees in any direction (back, forward, left andright) shall not vary from the reading taken in the normal position by an amount in excess of0.3 percent.
44、6.4 Dielectric:Each instrument shall be tested by the method of inspection listed in Paragraphs 6.4.1 and 6.4.2.SAE AS432 Revision B- 8 -6.4.1 Insulation Resistance: The insulation resistance measured at 200 volts DC for 5 secondsbetween all electrical circuits connected together and the metallic ca
45、se shall not be less than5 megohms. Insulation resistance measurements shall not be made to circuits where thepotential will appear across elements such as windings, resistors, capacitors, etc., since thismeasurement is intended only to determine adequacy of insulation.6.4.2 Overpotential Tests: The
46、 instrument shall not be damaged by the application of a test potentialbetween electrical circuits, and between electrical circuits and the metallic case. The testpotential shall be a sinusoidal voltage of a commercial frequency with an RMS value of fivetimes the maximum circuit voltage or per parag
47、raphs 6.4.2.1 or 6.4.2.2 whichever applies. Thepotential shall start from zero and be increased at a uniform rate to its test value. It shall bemaintained at this value for 5 seconds and then reduced at a uniform rate to zero. Since thesetests are intended to insure proper electrical isolation of th
48、e circuit components in question,these tests shall not be applied to circuits where the potential will appear across elements suchas windings, resistors, capacitors, etc.6.4.2.1 Hermetically sealed instruments shall be tested at 200 volts RMS.6.4.2.2 Circuits that operate at potentials below 15 volt
49、s are NOT to be subjected to overpotentialtests.6.5 Sealing:Hermetically sealed components shall be tested for leaks by means of a mass spectrometer typeof helium leak detector or equivalent. The leak rate shall not exceed 76 microns per hour percubic foot of filling gas at a pressure differential of one atmosphere.Note: A micron cubic foot per hour leak rate is defined as that gas leakage which would changethe pressure of one cubic foot volume by the amount of one micron (one millionth of ameter of mercury) in 1 hour.6.6 Generator Voltag
