1、_ SAE 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 voluntary, and its applicability and suitability for any particular use, including any patent infringement arising there
2、from, is the sole responsibility of the user.” 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 2013 SAE International All rights reserved. No part of this p
3、ublication 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 permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-497
4、0 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/AIR1336B AEROSPACE INFORMATION REPORT AIR1336 REV. B Issued 1975-05 Reaffirmed 20
5、07-08 Revised 2013-03 Superseding AIR1336A Ground Support Equipment Electrical Systems RATIONALE Revised to include updated information on alternator charging systems and electronic fuel injection systems. TABLE OF CONTENTS 1. SCOPE 3 1.1 Purpose . 3 2. APPLICABLE DOCUMENTS 3 2.1 SAE Publications .
6、3 3. MAJOR COMPONENTS OF VEHICLE ELECTRICAL SYSTEMS 3 3.1 Batteries 3 3.1.1 Wet-Charged Batteries . 4 3.1.2 Dry-Charged Batteries 4 3.1.3 Battery Ratings 4 3.1.4 Effect of Temperature on Capacity . 4 3.1.5 Battery Failures . 4 3.1.6 Battery Maintenance . 6 3.2 AC Charging System 7 3.2.1 Alternator .
7、 7 3.2.2 AC Voltage Regulator . 8 3.2.3 Wiring Circuit . 11 3.2.4 Troubleshooting the AC Charging System . 12 3.3 Ignition System (Gasoline Engine Installation) . 13 3.3.1 Distributor 13 3.3.2 Ignition Coil . 15 3.3.3 Ignition Resistor 16 3.3.4 Ignition Switch . 16 3.3.5 Spark Plugs . 16 3.3.6 Ignit
8、ion System Wiring 17 3.4 Cranking Motor 17 3.4.1 Frame and Field Assembly . 17 3.4.2 Armature Assembly . 18 3.4.3 Motor Drives 18 3.4.4 Magnetic Switches and Solenoids 20 3.4.5 Basic Circuits 20 3.4.6 Series-Parallel Circuits 21 3.4.7 Cranking Motor Maintenance 21 SAE AIR1336B Page 2 of 28 3.5 Elect
9、ronic Ignition System . 21 3.5.1 Components 21 3.5.2 Operation Description . 22 3.5.3 Routine Maintenance 22 4. ELECTRONIC FUEL INJECTION SYSTEMS 22 4.1 Purpose and Description . 22 4.2 Added Engine Protection 22 5. ALTERNATOR SELECTION (ADEQUATE SIZE REPLACEMENT) 23 5.1 Vehicle Electrical Load 23 5
10、.2 Percent of Operating Time at Idle . 24 5.3 Vehicle Battery Size 24 5.4 Lowest Expected Operating Temperature 24 5.5 Alternator Characteristics to be Considered . 24 5.5.1 Maximum Output Current Rating 24 5.5.2 Current Output at Engine Idle Speed 24 5.6 Steps in Selecting the Right Alternator . 25
11、 5.6.1 Determining the Ampere-Hour Requirements 25 6. NOTES 28 TABLE 1 23 TABLE 2 24 TABLE 3 25 TABLE 4 26 TABLE 5 26 TABLE 6 26 TABLE 7 26 SAE AIR1336B Page 3 of 28 1. SCOPE This SAE Aerospace Information Report (AIR) considers the following major areas: 1. major components and their ratings; 2. se
12、lection criteria for optimum design balance for electrical systems; 3. effects of operating conditions and environment on both maintenance and life of components; 4. trouble signals - their diagnosis and cure. 1.1 Purpose Electrical systems engineering is the modern concept of integrating load requi
13、rements with generator/alternator and battery capacity and regarding this electrical equipment as a complete system rather than a collection of independent units. The old adage “a chain is not stronger than its weakest link” is particularly valid for electrical circuits. So great care must be taken
14、in selection of equipment and in considering the operating position and environment in which the equipment is expected to function. 2. APPLICABLE DOCUMENTS The following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The ap
15、plicable 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 applicable laws and r
16、egulations 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 724-776-4970 (outside USA), www.sae.org. SAE J56 Road Vehicles - Alternators with Regulator
17、s - Test Methods and General Requirements SAE J539 Voltages for Diesel Electrical Systems SAE J1343 Information Relating to Duty Cycles and Average Power Requirements of Truck and Bus Engine Accessories SAE J1908 Electrical Grounding Practice 3. MAJOR COMPONENTS OF VEHICLE ELECTRICAL SYSTEMS 3.1 Bat
18、teries An electrochemical device for converting chemical energy into electrical energy with electrical current being produced by chemical reaction between grids or plates containing, alternately, sponge lead (Pb) in the negative plate and lead peroxide (Pb02) in the positive plate immersed in an ele
19、ctrolyte of 36% sulfuric acid and 64% water. A fully charged battery contains electrolyte with a specific gravity of 1.270 at 80 F (26.7 C). The plates are grouped with PVC separators between positive and negative plates forming an element. Multiple elements of plate groups are placed in cells of a
20、battery case with partitions separating the cells. Each cell has an approximate potential of 2 volts; three cells connected in series make up 6-volt batteries or six cells connected in series make up 12-volt batteries. SAE AIR1336B Page 4 of 28 3.1.1 Wet-Charged Batteries Those batteries fully charg
21、ed and activated at the factory. When not in use, they will slowly “self-discharge”. High temperatures accelerate this condition - at 100 F (37.8 C), a battery in a vehicle or in storage will completely discharge without use in 90 days. Storage in a cool place is mandatory. More recent vehicles util
22、ize maintenance free batteries which typically discharge at 2 to 3% per month. 3.1.2 Dry-Charged Batteries Those batteries fully charged at the factory but the cells are dry of electrolyte. Electrolyte is normally supplied in a plastic bag in correct amount. Such batteries can be stored indefinitely
23、 in any environment with no periodic service or recharging necessary during storage. It is “factory fresh” when electrolyte is added and ready for immediate use. Proper activation consists of adding electrolyte of 1.265 specific gravity to each cell. After several minutes, check level again. Once th
24、e full electrolyte charge has been added, only add water thereafter. To insure best performance: Check voltage at terminals - if less than 10 volts on 12-volt battery, it should be replaced. When temperature is 32 F (0 C) or when battery and electrolyte are not 60 F (15.6 C) or above, battery should
25、 be warmed by a boost charge of 15 amperes for 10 minutes - then check temperature of electrolyte. If not 60 F (15.6 C) or above, continue boost charge until above 60 F (15.6 C). 3.1.3 Battery Ratings 3.1.3.1 Definition The Cold Cranking Performance rating is the discharge load in amperes which a ne
26、w fully charged battery at 0 F (-17.8 C) can continuously deliver for 30 seconds and maintain a terminal voltage equal to or higher than 1.20 volts per cell. Note: Some manufacturers publish ratings at 32 F (0 C). Comparison of battery specifications must always be at the same temperature rating. 3.
27、1.3.2 Reserve Capacity Rating This rating is the length of time one can travel with minimum electric load (lights and engine ignition) and no alternator output. It is expressed at the time in minutes for a fully charged battery at 80 F (26.7 C), discharged at a constant 25 amperes, to reach a voltag
28、e of 1.75 volts/cell or 10.5 terminal volts. 3.1.4 Effect of Temperature on Capacity The cold rating of a battery is its cranking power at 0 F (-17.8 C) normally expressed in watts. The wattage rating is determined in controlled laboratory tests and obtained by multiplying the voltage by the current
29、. The example in cold rating capacity (3.1.3.2) shows 300 amperes x 7.6 volts = 2180 watts. For heavy-duty service a watt rating of 2500 or better is required. At 0 F (-17.8 C), the capacity of a battery at full charge is only 61% of its 80 F (26.7 C) normal full charge rating, at -20 F (-28.9 C) it
30、s capacity is only 45% of the normal 80 F (26.7 C) rating. At the same time, the load imposed on the battery by the cold engine increases due to the friction and lack of lubrication. At 0 F (-17.8 C) it is 250% greater, at -20 F (-28.9 C) it is 350% greater than the normal cranking load at 80 F (26.
31、7 C). In other words, at low temperatures, the battery is much smaller, the engine is much larger. Both the battery ratings of 20-hour rating at 80 F (26.7 C) in ampere-hours and the cold rating at 0 F (-17.8 C) should be considered in battery selection to meet vehicle electrical demands. 3.1.5 Batt
32、ery Failures There are five major reasons why batteries wear out prematurely: a. deep cycling (the most common cause); b. overcharging; SAE AIR1336B Page 5 of 28 c. excessive vibration; d. high temperature; e. improper watering. 3.1.5.1 Deep cycling occurs when a battery carries a large part of the
33、electrical load frequently then is recharged after each discharge period. This happens when: a. drivers leave lights or radio/transmitter on during extended coffee breaks or rest periods; b. low-speed, long-idle periods when battery carrying large load; c. night or winter driving when electrical loa
34、d exceeds generator/alternator capacity. This deep cycling condition causes the positive plates to grow due to sulfation, then shrink as charging converts sulfate back to lead peroxide. This expansion and contraction cycle loosens plate material so it sheds to the bottom of the battery case. Gradual
35、 deterioration takes place until a particularly heavy load occurs, such as a first cold morning start. The engine wont crank. Sudden failures occur when the sediment from plates fills chambers at the bottom of the battery case and a short circuit between positive and negative plate bottoms causes a
36、“dead” cell. This condition terminates the life of a battery. Solution: (1) Use a higher ampere-hour rated battery with more plates and greater reserve for handling more deep cycles. (2) Select a charging system balanced to the electrical load at idle engine speed. The alternator of proper capacity
37、and voltage regulator should be adjusted to give a slight charge rate with normal lights and other load. Specify the alternator cold output required. 3.1.5.2 Battery overcharge occurs from an excessively high setting of the voltage regulator which produces an excessively high electrolyte temperature
38、 in the battery. High temperatures can also result if the battery in installed in close proximity to hot surfaces such as exhaust manifolds. A tell-tale sign of overcharging is excessive battery water consumption. Normal consumption is about 1 ounce/100 hours (29.6 cc/100 hours). Check the electroly
39、te temperature with a service thermometer after extended operation - this should not exceed 125 F (51.7 C). Excessive temperatures result in rapid deterioration of the battery. Above 150 F (65.6 C) ambient temperature, the sealing compound softens and cell covers push up on the positive end. At this
40、 sign, severe damage has already been done. Solution: (1) Reduce voltage regulator setting. Both transistor and vibrating contact type offer external adjustment. Alternators with internal voltage regulators can not be adjusted. The alternator must be replaced if overcharging. Keep track of water con
41、sumption and specific gravity reading carefully. The factory settings are usually too high for airline ground support operations. (2) Move battery to a cooler location. Equipment design often compromises the space for locating a battery. It is imperative to move or insulate the battery from “hot spo
42、ts”. 3.1.5.3 Vibration shortens battery life by speeding up shedding and causes plate and separator wear. The battery carrier should securely hold the case of the battery. Solution: (1) Locate battery where it is subjected to minimum vibration forces. (2) An acid-resistant rubber pad 1/8 inch (3 mm)
43、 thick placed under the case in the battery carrier sill compensates for irregularities and minimizes localized stresses. (3) Check the carrier hold-down device. SAE AIR1336B Page 6 of 28 3.1.5.4 High electrolyte temperature due to excessive charging or “hot spot” environment causes premature wear o
44、ut. Temperatures over 125 F (51.7 C) in the electrolyte cause “boil out” of the electrolyte, corroding terminals, carrier case, and hold-downs. Solution: (1) Check location in vehicle. (2) Check charging rate as above. 3.1.5.5 Overwatering causes electrolyte loss and poor performance. Too little aci
45、d remains in the electrolyte in each cell and the overflow causes corrosion of terminals and carrier case. Solution: (1) Dont overwater. 3.1.6 Battery Maintenance Both shop maintenance and on-vehicle battery care are most important. Service records of each battery throughout its life are very necess
46、ary to check preventive maintenance and service. 3.1.6.1 On-Vehicle Maintenance 3.1.6.1.1 Visual Inspection Check electrolyte level; clean corrosion off terminals; check tightness of battery cables; inspect for broken case or pushed up cell cover; check tightness of hold-down device. 3.1.6.1.2 Light
47、 Load Test Place a load on the battery by holding the starter switch “on” for 3 seconds or until engine starts. If engine starts, turn off immediately. Next, turn lights “on”. After 1 minute and with lights still “on”, read the voltage with a voltmeter with 0.01 volt divisions. If battery reads 11.7
48、 volts or more - the battery is good. Readings less than 11.7 volts require the battery be recharged and retested with the above test. If it still fails to read 11.7 volts, replace the battery. Electric resistance load meters can also be employed for this type of test. Connect the meter and depress
49、the switch to load the battery. 3.1.6.1.3 Slow Charge and Boost Charge of Battery Slow charge is the best method of recharging a discharged battery. A slow charge is at a rate of 5 amperes for 24 hours or at a rate of 7% of ampere hour rating. Full charge of a battery is indicated when cell gravity readings do not increase when checked at three times at intervals 1 hour apart (1.230 to 1.310)
