REG KSC-MMA-1985-79 REV 6-2008 STANDARD TEST METHOD FOR EVALUATING TRIBOELECTRIC CHARGE GENERATION AND DECAY.pdf

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1、NASA KSC Export Control Office (ECO) Export Determination Stamp EDDS # 8508 TITLE OF DOCUMENT: 1) KSC-MMA-1985-79, Revision 4, June 22, 2000, Standard Test Method For Evaluating Triboelectric Charge Generation and Decay SENSITIVE BUT UNCLASSIFIED (SBU) INSTRUCTIONS: This item must be reviewed under

2、the requirements for “Sensitive But Unclassified Information” as described in NPR 1600.1. Material that is export-sensitive is automatically considered to contain SBU and does not require an SBU Reviewer signature. Material that is not export-sensitive must be reviewed for SBU and documented on NASA

3、 Form 1686. Yes No SBU Reviewers Signature Date Document contains SBU? 6/11/2008 EXPORT CONTROL (EC) INSTRUCTIONS: If the document includes export-controlled data, contact your directorate Export Control Rep or the KSC ECO Help Desk (867-9209) for a determination of the proper export category. ECO R

4、eviewers Name and Organization ECO Reviewers Signature Date William J. Collins, NASA KSC ECO 6/11/2008 EXPORT DETERMINATION (; one box only) EAR 99 NLR EAR 99 NLR The information contained in the document is technical in content, but is not technical data as defined by the ITAR or the EAR, and there

5、fore is EAR 99 NLR (no export license required). General Prohibition Six (Embargo) applies to all items subject to the EAR, i.e. items on the CCL and within EAR 99 NLR. You may not make an export or re-export contrary to the provisions of part 746 (Embargos and Other Special Controls) of the EAR and

6、 22 CFR part 126.1 of the ITAR. EAR Controlled This document is within the purview of the Export Administration Regulations (EAR), 15 CFR 730-774, and is export controlled. It may not be transferred to foreign nationals in the U.S. or abroad without specific approval of a knowledgeable NASA export c

7、ontrol official, and/or unless an export license or license exception is obtained/available from the Bureau of Industry and Security, United States Department of Commerce. Violations of these regulations are punishable by fine, imprisonment, or both. ITAR Controlled This document contains informatio

8、n which falls under the purview of the U.S. Munitions List (USML), as defined in the International Traffic in Arms Regulations (ITAR), 22 CFR 120-130, and is export controlled. It shall not be transferred to foreign nationals, in the U.S. or abroad, without specific approval of a knowledgeable NASA

9、export control official, and/or unless an export license or license exemption is obtained/available from the United States Department of State. Violations of these regulations are punishable by fine, imprisonment, or both. (Stamp Revision: (10-2-2007) Provided by IHSNot for ResaleNo reproduction or

10、networking permitted without license from IHS-,-,-MMA-1985-79, Rev 6 STANDARD TEST METHOD FOR EVALUATING TRIBOELECTRIC CHARGE GENERATION AND DECAY Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MMA-1985-79, Rev 6 TEST REPORT Standard Test Method for

11、 Evaluating Triboelectric Charge Generation and Decay ISSUED BY National Aeronautics and Space Administration Kennedy Space Center Spaceport Engineering and the felt may be washed with soap and water, rinsed in alcohol, and dried. 4.5 The surface of unused PTFE felt has tightly knit fibers. When the

12、se become loose from repeated use, the felt must be discarded. 4.6 The wheel is attached to a 1/8 HP electric motor. Contact force between the rubbing wheel and the sample is maintained at 3 pounds by using a dead weight and a pulley system. 4.7 A capacitive sensor (Keithley 2501) provides a non-con

13、tact reading of the static voltage developed on the sample. This unit provides 10-4voltage attenuation. 4.8 The pneumatic sample transfer mechanism moves the sample from the rubbing to the sensing position within 0.5 second. 4.9 The controller consists of electro-pneumatic valves and switches for au

14、tomatic operation of the device. Contact time is also adjusted by the controller. Excessive rubbing may change the sample texture or cause 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MMA-1985-79, Rev 6 damage to the rubbing medium. Too brief a

15、contact (e.g., less than 1 second) may generate insufficient charge. 4.10 Keithley 6514 electrometer amplifies the signal from the sensor. 4.11 Analog output from the electrometer is fed into an analog-to-digital data acquisition system. A micro switch is attached to the base of the motor slide. As

16、the rubbing motor retracts from the sample, the micro switch is activated and a triggering signal is generated to initiate data acquisition. 5.0 PREPARATION OF TEST SAMPLES 5.1 Cut three 8-inch diameter samples from the test material. Precondition the samples as mounted in holders in the desired tes

17、t environment for a minimum of 24 hours. Gloves are required during sample handling in order to prevent contamination. 5.2 When less than 3 samples are prepared due to insufficient test material, the discrepancy must be noted in the test report. 6.0 TEST PROCEDURE 6.1 Turn on ionizer for sufficient

18、length of time to remove any residual static charge from the wheel and test sample. 6.2 Turn on electrometer and data acquisition system. 6.3 Turn on rubbing motor and verify 200 rpm. 6.4 Place sample holder on the sample carriage. 6.5 Activate Clamp on the controller. 6.6 Briefly press and then rel

19、ease Zero Check on the electrometer. 6.7 Arm the data acquisition system. 6.8 Activate Run on the controller. 6.9 Record peak, 1/2 s, 1 s, 2 s, 3 s, 4s, and 5 s voltage. 6.10 Repeat the test for all 3 samples except when failure occurs. Both sides of the sample need to be tested, unless they are ide

20、ntical. 7.0 CALIBRATION 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MMA-1985-79, Rev 6 7.1 The system must be calibrated when an electronic component is replaced or when mechanical changes are made. Regular calibration must be done every 6 mont

21、hs. 7.2 A test plate connected to a calibrated DC power supply is used for system calibration. The test plate is a 5 inch diameter metal disc supported on an insulating plastic sheet. 7.3 Apply a DC voltage to the test plate and check the electrometer display. Adjust the distance between the sensor

22、and the test plate, if necessary. Verify that the rear analog output of the electrometer matches the front display. If there is a discrepancy, send the unit to KSC Calibration for correction. Trigger data acquisition system. Adjust gain and zero of the data acquisition system, if necessary. When the

23、 readout of the data acquisition system is within 97% of the applied voltage at +500 volts, and within 95% at +2000 volts, the system is considered calibrated. 7.4 A glass thermometer with graduation of 0.2 oC is adequate for temperature measurement. It must be periodically calibrated by KSC Calibra

24、tion. Relative humidity (RH) sensors can be calibrated in the lab by using the reference solutions defined in ASTM E104. Yearly calibration is required. 7.5 7.6 As the PTFE felt becomes used, fibers become loose and tribocharging characteristics change. The felt needs to be replaced. Charge plate mo

25、nitor such as Monroe 286A can be used to determine the time of replacement. Place a rubbing wheel on the plate with the felt down, and measure charge as the wheel is slid on the plate. Variation greater than 10% from new requires felt replacement. 8.0 TEST REPORT A test report includes the following

26、 minimum information: job number, test method and revision number, sample description, test data (peak, 0.5s, 1s, 2s, 3, 5s voltage), temperature, relative humidity, calibration information, and name of test conductor. 9.0 CHANGES IN REV 6 9.1 An automated test device replaced a manually operated un

27、it. Also, a digital electrometer (Keithley 6514) replaced an analog unit (Keithley 610C). 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MMA-1985-79, Rev 6 7 9.2 Contact time was changed from 10 seconds to 10 seconds or less. The previous 10 second requirement originated from the time that a test technician needed to operate the device manually. 9.3 The condition for discarding used PTFE felt was added. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-