1、 Test Procedure for Electrical Ground Attachments The research data, analysis, conclusion, opinions and other contents of this document are solely the product of the authors. Neither the Society of Automotive Engineers, Inc. (SAE) nor the United States Council for Automotive Research (USCAR) certifi
2、es the compliance of any products with the requirements of nor makes any representations as to the accuracy of the contents of this document nor to its applicability for purpose. It is the sole responsibility of the user of this document to determine whether or not it is applicable for their purpose
3、s. Copyright 2003, USCAR All rights reserved. Printed in U.S.A. Issued August 2003 SAE/USCAR-26 QUESTIONS REGARDING THIS DOCUMENT: (724) 772-8518 FAX (724) 776-3036 TO PLACE A DOCUMENT ORDER: (724) 776-4970 FAX (724) 776-0790 SUMMARY OF CONTENTS 1. SCOPE 2 2. REFERENCES2 3. DEFINITIONS . 2 4. GENERA
4、L REQUIREMENTS. 2 4.1. Test Equipment and Tolerances . 2 4.1.1. Test tolerances are per SAE/USCAR-2 except as noted 2 4.1.2. Test equipment required is shown in table 1. 2 4.1.3. Test Fixture .3 4.2. Test Samples 3 4.2.1. Sample Quantity 3 4.2.2. Test Coupons 4 4.2.3. Terminal Preparation. 4 4.2.4.
5、Ground Wire Attachment to Test Coupon . 4 4.2.5. Assembly of Test Samples 5 4.2.6. Grouping of Samples. 5 4.3. Test Procedures 5 4.3.1. Biasing Samples 5 4.3.2. Test Schedule . 5 4.4. Thermal Shock 6 4.5. Random Vibration . 7 4.6. Temperature/Humidity Cycling 7 4.7. Salt Fog. 7 4.8. Resistance Measu
6、rement . 7 5. ACCEPTANCE CRITERIA . 7 6. SUMMARY OF TEST DATA. 8 6.1. Test Information 8 7. FIGURES 8 SAE/USCAR-26 Issued August 2003 TEST PROCEDURE FOR ELECTRICAL GROUND ATTACHMENTS - 2 - 1. SCOPE This test procedure is intended to evaluate and/or validate electrical ground schemes for use on the b
7、ody or chassis. There are two classes based on the expected environmental conditions. Exposed Grounds can be located anywhere in the vehicle (except on the powertrain) and is the class for which most schemes should be tested. Unexposed Grounds can only be used in the passenger compartment or trunk a
8、nd as such are special cases. This procedure as written is not intended for testing powertrain grounds where high temperatures and vibration levels may be encountered. These situations may require modifications to this procedure and are left to the Responsible Engineer to determine. This specificati
9、on does not specifically address validation of terminal to wire electrical crimps. Crimps are tested to SAE/USCAR-21 2. REFERENCES ASTM B-117 Standard Practice for Operating Salt Spray (Fog) Apparatus. SAE/USCAR-2 Performance Specification for Automotive Electrical Connector Systems Refer to SAE/USC
10、AR-2 for other Reference Documents Required. 3. DEFINITIONS Exposed Ground Points - Exposed Ground Points can be located anywhere in the vehicle. Most ground schemes should be tested to this profile. Unexposed Ground Points - Unexposed Ground Points can only be used in the passenger compartment or t
11、runk and as such are special cases. Life Cycle - The number of life cycles run during the conditioning procedure depends on the desired confidence and reliability levels. For purposes of this document, one life cycle equals 6 years/100,000 miles. 4. GENERAL REQUIREMENTS Refer to SAE/USCAR-2 for Gene
12、ral Requirements. The test equipment list is replaced with the following: 4.1. Test Equipment and Tolerances 4.1.1. Test tolerances are per SAE/USCAR-2 except as noted. 4.1.2. Test equipment required is shown in table 1 SAE/USCAR-26 Issued August 2003 TEST PROCEDURE FOR ELECTRICAL GROUND ATTACHMENTS
13、 - 3 - Equipment Description Temperature/Humidity Cabinet Temperature control of +/-2oC up to 65oC and relative humidity control of +/-2% up to 90% Thermal shock equipment -40oC to 85oC or +125oC per para. 4.4 Power Supply for biasing samples Per paragraph 4.3.1. Power Supply for taking measurements
14、. Capable of sustaining 5 volts at a minimum of 10 amps shall be set to current limit at 10 0.1 A Milli-volt meter Capable of measuring at least 0.01 mV Dry-off Environment: Temperature Humidity 60oC +/-2o40-50% RH Salt Fog Chamber Per ASTM B117 (+40oC) Table 1 Test Equipment and Conditions 4.1.3. T
15、est Fixture All conditioning and testing shall be conducted with the test specimens mounted to a test fixture made from a thermally non-conductive material. The test fixture shall be designed so that test samples will remain mounted to the same fixture throughout the entire test. (If a fixture becom
16、es unusable once the test has started and the samples are transferred to a different fixture, this should be recorded along with the data.) The test fixture shall have provisions to securely fix all wires to the fixture such that the wire length from the terminal to the fixture attachment point shal
17、l be 150 +/- 50mm. 4.2. Test Samples 4.2.1. Sample Quantity For validation, the number of required samples to be tested without failure is 20. Larger sample quantities may be tested depending upon the desired reliability and confidence levels. The number of samples tested and life cycles run shall b
18、e recorded as part of the test data. Running this test for only one life cycle is unacceptable for validation. For evaluation testing, one, two or three life cycle can be used with any number of samples - though a minimum of ten is recommended. SAE/USCAR-26 Issued August 2003 TEST PROCEDURE FOR ELEC
19、TRICAL GROUND ATTACHMENTS - 4 - 4.2.2. Test Coupons The actual shape of the test coupon is not critical, but the size should be kept at a minimum to reduce the thermal mass. Figure 1 shows one possible configuration. The number of parts attached to a coupon is also not critical, but again the coupon
20、 size should be kept at a minimum. When performing a test to compare parameters, all coupons in the test shall be the same size. Coupons should be made of 0.8 mm galvanized steel for general fastener testing. Where specific fastener or vehicle location requirements dictate otherwise, coupons should
21、simulate the actual mating material to be used in production. (i.e. cast iron, aluminum.) The coupons shall be treated with production intent coating and processes. The actual formulation and methods of application shall be included as part of the test data. Provided the area of attachment is proper
22、ly coated, incomplete sample coverage is not a concern. 4.2.3. Terminal Preparation The samples will be tested using a four-wire scheme; therefore each terminal shall have two wires attached to it. All wires shall be multi-strand 0.5mm2with cross-linked insulation, unless the purpose of this test di
23、ctates otherwise. Wires with PVC insulation shall not be tested. The two wires shall both be directly attached to the terminal and either soldered or welded in place (see Figure 2a). 4.2.4. Ground Wire Attachment to Test Coupon Two ground wires shall be attached to each test coupon. They shall be th
24、e same size and have the same type of insulation as the power wires. Both wires shall be directly attached to the test coupon and either soldered or welded in place. The voltage sense wire shall be located within 30mm of the attachment point (see Figure 2b). Provided the above criteria are met: a. I
25、f multiple parts are attached to the same coupon, they may share both ground wires. One ground wire may be daisy chained from coupon to coupon, but a separate voltage sense wire shall be used for each attachment/coupon. b. The area of attachment to the coupons may be coated. SAE/USCAR-26 Issued Augu
26、st 2003 TEST PROCEDURE FOR ELECTRICAL GROUND ATTACHMENTS - 5 - 4.2.5. Assembly of Test Samples Terminals shall lie parallel with respect to all mating surfaces (see Figure 2c). Additionally, if terminals are stacked, they shall be arranged so that there is no interference between crimp barrels (see
27、Figure 2d). Torque all fasteners to the low end of their respective torque ranges, unless torque variation is a consideration of the test. The torque for each fastener shall be included as part of the test data. The method, tool and tool settings used to torque the fasteners shall be the same for al
28、l similar fasteners, unless method and/or tool variability is a consideration of the test. The method, tool and tool settings used shall be included as part of the test data. Each attachment point shall be given a unique designation to be used for recording data. This designation shall be permanentl
29、y marked on the test coupon. If terminals are stacked, a uniform method of distinguishing the position of each terminal shall be used (e.g. #24t is the top terminal on fastener #24). 4.2.6. Grouping of Samples When performing a test to compare parameters and multiple groups of samples are to be test
30、ed, samples of each configuration shall be divided among all the groups. As a result, each group will be comprised of samples from each of the test configurations. 4.3. Test Procedures 4.3.1. Biasing Samples Samples shall be powered (biased) during all phases of the conditioning procedures except Th
31、ermal Shock and vibration. Any number of samples may be connected in parallel to reduce the number of power supplies required. Each power supply shall be set to current limit based on the number of samples connected to it: a. For 1 to 5 samples, the current limit shall be set to x amps 0.1 amps, whe
32、re x is the number of samples. b. For more that 5 samples, the current limit shall be set to x amps 0.5 amps, where x is the number of samples. 4.3.2. Test Schedule Repeat the cycle shown in figure 2 on the electrically biased samples. Additional life cycles may be run at the option of the test requ
33、estor. The test can be continued throughout weekends to decrease the overall test time. Samples shall be oriented with surfaces of the coupons horizontal so that water does not readily drain away during the Temperature/Humidity and Salt Fog conditioning procedures. SAE/USCAR-26 Issued August 2003 TE
34、ST PROCEDURE FOR ELECTRICAL GROUND ATTACHMENTS - 6 - Figure 2 Test Schedule 4.4. Thermal Shock Subject the samples to 50 cycles of the following: 2 hours at 40oC 2 hours at Tmax, where Tmax= +125oC for Exposed Grounds +85oC for Un-exposed Grounds SAE/USCAR-26 Issued August 2003 TEST PROCEDURE FOR EL
35、ECTRICAL GROUND ATTACHMENTS - 7 - 4.5. Random Vibration Subject samples to random vibration profile for “Sprung Portions of Vehicle Not Coupled to Engine” per SAE/USCAR-2 (1.81G rms) for 8 hours in each of the three mutually perpendicular axes. Total exposure time is 24 hours. 4.6. Temperature/Humid
36、ity Cycling Each sample shall be exposed to 25 cycles of the Temperature/Humidity Cycle per SAE/USCAR-2. Test Temperatures shall be 125oC for Exposed Grounds and 85oC for Un-exposed Grounds. Power shall be applied throughout this test as described in paragraph 4.3.1. 4.7. Salt Fog Each sample shall
37、be exposed to salt fog per ASTM B117 at +40oC. Exposure shall be 96 hours for schemes used in Exposed areas and 48 hours for schemes used only in Unexposed areas. Power shall be applied throughout this test as described in paragraph 4.3.1 4.8. Resistance Measurement The following procedure shall be
38、performed separately on each sample. Connect the measurement power supply as described in Table 1 to the sample using two of the leads. Using a mV meter as specified in Table 1, measure and record the voltage drop across the other two leads on each sample. Complete the Visual Examination procedure a
39、s specified in SAE/USCAR-2. 5. ACCEPTANCE CRITERIA 1. The maximum voltage drop recorded in paragraph 4.8 shall not exceed 1 mV per amp. 2. The change in voltage drop () from beginning to end of all conditioning procedures shall not exceed 0.5mV per amp. 3. Samples shall not exhibit heavy corrosion t
40、hat could result in mechanical or electrical failure. 4. Sample groups shall conform to the statistical requirements of paragraph 4.2.1. SAE/USCAR-26 Issued August 2003 TEST PROCEDURE FOR ELECTRICAL GROUND ATTACHMENTS - 8 - 6. SUMMARY OF TEST DATA 6.1. Test Information Record at minimum the followin
41、g information in the test report: null The manufacturer, model number and last calibration date of all conditioning and measurement equipment. null Any deviations from the outlined procedure null Sample quantity null Number of life cycles run null A diagram of the test coupon including the material.
42、 Finish and physical dimensions. null The formulation and method of application of the coating applied (e.g. ELPO primer) to the coupons. null Method of attachment of the sense wire (crimped in the terminal or connected to the power wire). null Torque for each fastener. null Method, tool and tool se
43、ttings used to torque fasteners. null Whether terminals are stacked. 7. FIGURES: 20 35 7510 mm Diameter Optional for processing coupon 10 10All Dimensions are in mmAll Non-hole Dimensions are 2 mm Approximate center of fastener 40 Figure 1 - Test Coupon Example SAE/USCAR-26 Issued August 2003 TEST P
44、ROCEDURE FOR ELECTRICAL GROUND ATTACHMENTS - 9 - Use either wirefor power, theother for senseFigure 2a - Power Wire Attachment When Terminal-to-Cable Attachment Not Tested 30 mmMaxSense WirePower GroundWire (may beattached in samelocation as SenseWire)Figure 2b - Ground Wire Attachment Not Acceptabl
45、e(Terminal NotFlat)Acceptable Not Acceptable(Both TerminalsNot Flat)AcceptableFigure 2c - Assembly of Terminal on Test Coupon AcceptableNot Acceptable(Terminal BarrelsOverlap)Not Acceptable(Lead-In for TerminalBarrels Overlap)Figure 2d - Alignment of Stacked Terminals SAE/USCAR-26 Issued August 2003 TEST PROCEDURE FOR ELECTRICAL GROUND ATTACHMENTS - 10 - Appendix A - Change Record Date Section Summary of Changes Notes 8-11-03 All Release
