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Ron Brewer

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  • 机译 海上雷电防护的复杂性
    • 作者:Ron Brewer;
    • 刊名:Evaluation Engineering
    • 2011年第5期
    摘要:Most boats and ships usually ride out a thunderstorm and the high winds, tornados, hail, and floods it can produce. But the ESD event called lightning that it creates is a very different situation. Lightning can be extremely hazardous, particularly to a boat's structure, electrical and electronic equipment, and crew. When far from shore, there is no safe haven when a storm and accompanying lightning occur. As a result, lightning protection must be addressed, and the effective method is a lightning protection system (LPS), a designated intentional low-impedance path for the lightning current to take to earth should a lightning leader come within striking distance of the LPS. An LPS is a bonding, grounding, and shielding configuration made of four distinct parts: air terminals and down conductors discussed in Part 1 and a low-impedance ground system and flash-over protection.
  • 机译 更好的EMC测试的五个步骤第1部分
    • 作者:Ron Brewer;
    • 刊名:Evaluation Engineering
    • 2010年第5期
    摘要:In the early days, just after the FCC released Part 15 J to control those noisy digital systems, a company that wanted to make sure its product passed asked us to provide a complete and exhaustive data set. The system was complex with several modes of operation.rnAfter accounting for the time required to run a full equipment cycle for each mode at each receiver bandwidth and antenna position and calculating that it would take 13.46 years to perform all the testing for the data set they wanted, the company changed itsrnrequirements. When the testing was finally completed, it had taken about four days to do the job, but there never were any in-the-field failures.
  • 机译 更好的EMC测试的五个步骤第二部分
    • 作者:Ron Brewer;
    • 刊名:Evaluation Engineering
    • 2010年第6期
    摘要:This is the second article in a two-part series discussing EMC test planning. The first article, which appeared in the May issue of EE, focused on establishing test objectives and pretest requirements covered Steps 1 and 2. Part 2 concludes with Steps 3, 4, and 5.rnEssentially, five separate steps are involved in performing an EMC test regardless of whether it is for design/ development or for formal acceptance:rn1. Establish the test objectives.rn2. Do a pretest requirements analysis.rn3. Perform the testing.rn4. Evaluate the results.rn5. Correct any problems.
  • 机译 现场EMC测试第1部分
    • 作者:Ron Brewer;
    • 刊名:Evaluation Engineering
    • 2010年第11期
    摘要:Performing EMC tests on large electronic equipment can be problematic especially if the EUTs can't be moved. It doesn't matter how large a test chamber may be, some EUTs must be tested in situ. Here are a few examples.rn1.Ares I Rocket: a 308-ft tall × 18-ft dia unit that can be launched but not moved after assembly: Multiple power, control, and signal cables run the length of the system to various redundant analog and digital sensors and equipment located at its top and bottom.
  • 机译 在培训中找到卓越
    • 作者:RON BREWER;
    • 刊名:EHS Today: The Magazine for Environment,Health and Safety Leaders
    • 2010年第5期
    摘要:Too often when it comes to creating a safe environment, organizations haven't taken the time to understand and complete what must be done.To implement a worthwhile training program, it's important that you first focus on what many consider the foundation of any successful training program.This includes four key steps:
  • 机译 安全乘搭
    • 作者:Ron Brewer;
    • 刊名:Plant engineering
    • 2009年第8期
    摘要:Osha estimates that approximately 680,400 lift truck accidents occur each year. The hard fact is that most of these accidents can be prevented with proper training and the adoption of best practices and safe work habits.rnHere are six primary areas businesses should focus on to help create a safe environment for lift truck operation.rnWhen done properly, operator training should consist of a logical progression of events that result in informed, skilled operators who consistently practice safe work habits.
  • 机译 设计和开发测试:第1部分
    • 作者:Ron Brewer;
    • 刊名:Evaluation Engineering
    • 2009年第8期
    摘要:Large companies can afford a $ 10 in $30 million facility necessary for EMC qualification testing plus the additional expenses for the personnel to staff the operation. It could be argued that they can't afford not to provide such facilities. On the other hand, small and medium-sized companies typically cannot justify their own fully equipped EMC qualification test facility...yet there still is a need to perform design, development, and troubleshooting tests.
  • 机译 3,000 dB和上升
    • 作者:Ron Brewer;
    • 刊名:Evaluation Engineering
    • 2008年第2期
    摘要:It's hard to imagine that a shielded enclosure could provide 3,000-dB RF attenuation, but based on the equations that define such values, it's not a problem. Shielding effectiveness is a function of frequency, and the higher the frequency, the greater the material attenuation. It just keeps rising.
  • 机译 系统EMC设计与分析
    • 作者:Ron Brewer;
    • 刊名:Evaluation Engineering
    • 2008年第10期
    摘要:I'm working on a new system that does everything for everyone. I'll take one of those, and one of those, and two of these. Do you have it from some other supplier in blue? Our sales/marketing department wants to offer it in blue. OK, wrap em up! Wouldn't it be great if designing new military systems with commercial-off-the-shelf (COTS) hardware were this easy? We could speed up our product time to market and all but eliminate development costs. It's possible that our profit margin will be skimpy, and our customers might not think we were the most innovative company since our products are limited to existing components.
  • 机译 系统EMC设计和分析:第2部分
    • 作者:Ron Brewer;
    • 刊名:Evaluation Engineering
    • 2008年第11期
    摘要:This is the second article in a two-part series discussing the fundamentals of systems EMC design and analysis that are quite different from those used for subsystems. The first article, which appeared in the October issue of EE-Evalu-ation Engineering, discussed the effects of four interrelated factors-frequency, amplitude, spatial separation, and timing-on the RF environment in which an EMC-compliant system must function.
  • 机译 设计射频屏蔽外壳外壳设计中必须考虑到预期的问题
    • 作者:RON BREWER;
    • 刊名:Interference Technology: EMC Directory & Design Guide
    • 2008年第2008期
    摘要:Shielding has been with us a long long time. Early AM radios had shielded RF and IF transformers, shielded electron tubes, and compartmentalized shielded chassis. These shields were necessary to prevent RF pickup, feedback, and oscillation by the electron tubes, radiation from the local oscillator, RF contamination of the IF strip, and crosstalk within circuit wiring. By the mid-1940s, there were a number of military RFI specifications to be met, and RF gaskets were in use (beryllium copper, silver elastomers, and monel wire mesh). In 1956 a tri-service shielded enclosure measurement specification was released called MIL-STD-285. Fifty years later it is still being used to evaluate shielded enclosures. This standard has been used to measure almost every kind of shielded enclosure, but it was originally designed to measure the enclosure attenuation provided for sources located outside the enclosure. How the enclosure is measured is significant. The measurement technique should reflect the proposed use of the enclosure.
  • 机译 航天器EMC问题第1部分
    • 作者:Ron Brewer;
    • 刊名:Evaluation Engineering
    • 2007年第4期
    摘要:There are many wise old sayings within the aerospace industry. One of those sage aerospace tenets conveys the differences between scientists and engineers: When the rocket gets off its pad and the payload successfully reaches its destination, the scientists have had another breakthrough. But let that rocket blow up on the pad and the engineers have screwed up again.
  • 机译 航天器EMC问题第2部分
    • 作者:Ron Brewer;
    • 刊名:Evaluation Engineering
    • 2007年第5期
    摘要:One sage aerospace tenet conveys the difference between scientists and engineers: When the rocket gets off its pad and the payload successfully reaches its destination, the scientists have had another breakthrough. But let that rocket blow up on the pad and the engineers have screwed up again. An EMC-induced launch failure generally is not as spectacular as a solid-fuel rocket blowing up on the pad, but it certainly has accounted for a large number of very expensive mission losses.
  • 机译 发生EMC故障
    • 作者:Ron Brewer;
    • 刊名:Evaluation Engineering
    • 2007年第12期
    摘要:EMC testing for components and subsystems has evolved greatly over the last 40 years since MIL-STD-461/461A was released. This design and test-procedures document was a credible attempt at standardizing EMC tests and has formed the basis for many other government and industrial procedures for equipment and subsystem tests. Unfortunately, it was not designed for system-level testing, and any attempt to use the procedure for in situ operational tests is futile. Unfortunately, duplicating the operational EME is impossible. Even coming close is very expensive because of the continually worsening adverse RF and physical environment such as shock and vibration, ESD, lightning, salt fog, or rain. These changing environmental conditions directly affect the performance of the EUT device. Since the EME is continually evolving, it is not possible to guarantee future performance of a new EUT based on the performance of the same or similar devices that may have been fielded in the past. This is especially true if an EMCSM was not established. Without previous EMCSM data or current EMC test data that provides the susceptibility profile, it can only be assumed that the equipment is at the threshold of failure with respect to the original EMC test environment. If the EMC test standard used was MIL-STD-461C, that standard defines a 20-year-old environment that is not adequate to protect today's equipment. Equipment often fails in its operational environment, and manufacturers chalk it up to unknown causes when, in many cases, the problem is an EMC susceptibility problem. All such failures should be investigated and a post-mortem reporting procedure developed to determine the cause of the failure so future systems won't have the same problem. When it's not possible to test like you fly and provide reasonable assurance that the system will work in an adverse environment, use a modern standard tailored to the most flight-like conditions possible and determine an EMCSM during the performance of the test. The recommended minimum EMCSM is 6 dB, but 12 dB would be better.
  • 机译 海上雷电防护的复杂性第1部分
    • 作者:Ron Brewer;
    • 刊名:Evaluation Engineering
    • 2011年第4期
    摘要:Without question, a thunderstorm is very dangerous. It can produce high winds, tornados, hail, and floods, which usually are not big problems for boats or ships. But it also creates ESD events called lightning. And, lightning discharges can be a serious hazard to a boat's structure, electrical and electronic equipment, and crew. Even if the lightning strike does not sink the vessel, a single stroke can critically injure crew members, disable the boat or ship, and destroy all electronics, leaving the vessel stranded with a life-threatening emergency and no means of communications. More people are killed each year by lightning than by any other weather-related phenomena. And when far from shore, there is no safe haven.
  • 机译 现场EMC测试
    • 作者:Ron Brewer;
    • 刊名:Evaluation Engineering
    • 2010年第12期
    摘要:In situ measurements are difficult, time-consuming, and expensive. Characteristically, some EMC problems show up after installation because of unforeseen interference with the ambient RF environment. As a result, organizations now use a 9-dB safety margin for large-scale systems to mitigate EMC problems after installation.
  • 机译 航空航天外壳的接缝孔泄漏
    • 作者:Ron Brewer;
    • 刊名:Evaluation Engineering
    • 2009年第3期
    摘要:An RF shielded enclosure is not a mechanical solution to an electrical problem. It is an electrical solution to an electrical problem. However, it still has to function properly in its operational environment. That may require a lot of mechanical design expertise. Ideally, the enclosure should be constructed with no seams. Maybe someday a high-strength conductive paste will allow enclosure manufacturers to approximate the no-seam configuration. Meanwhile, most enclosure manufacturers use RF gasket materials to maintain contact across the seams.
  • 机译 设计与开发测试第2部分
    • 作者:Ron Brewer;
    • 刊名:Evaluation Engineering
    • 2009年第9期
    摘要:This article briefly covers testing for design, development, and troubleshooting of CE, CS, RE, and RS EMC problems. For more information, some excellent books can help fill in the blanks:rn1. EMI Troubleshooting Techniques, Michel Mardiguian, McGraw Hill, 1999.rn2. The Technician EMI Handbook: Clues and Solutions, Joseph Carr, Newnes, 2000.rn3. High-Frequency Measurements and Noise in Electronic Systems, Doug Smith, John Wiley, 1992.
  • 机译 辐射敏感性
    • 作者:Ron Brewer;
    • 刊名:Evaluation Engineering
    • 2008年第5期
    摘要:Some EMC tests are about as exciting as watching grass grow. However, I must admit that today's computer control beats the previous procedures that included highly manual testing followed by lengthy and often very tedious recheck-ing, recording, and analyzing results. Throughout the years, the electric field (EF) radiated susceptibility/immunity test remains the most fun EMC test to run. It's so easy to produce the required EF at any desired frequency that we can really concentrate on testing the EUT.
  • 机译 评估雷电敏感性
    • 作者:Ron Brewer;
    • 刊名:Evaluation Engineering
    • 2008年第7期
    摘要:They say that lightning doesn't strike the same place twice. Wrong! The Empire State building has been struck thousands of times, so often that it was used as a test object during early lightning studies. On a macroscopic level, when an object or person is struck by lightning, it probably has been struck multiple times in that single event because of the way the lightning waveform is generated. A thundercloud behaves like an electrostatic charge generator. Charge separation occurs when ice particles circulating within the cloud and bumping into one another take on or lose electrons. During collisions, small particles give up electrons to larger particles regardless of whether they are ice, dust, flour, or whatever. Because the smaller ice particles are lighter, they are blown higher in the cloud so the top of the cloud becomes increasingly more positive and the bottom more negative.

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