Below are the questions asked during the live event, along with their respective answers.
A: This always needs to be based on your career goals. In your current role, understanding the test equipment and capabilities along with analysis of the test results. The ability to determine that the test results make sense allows recognition of test anomalies and helps identify compliance issues. For example, a CS114 test that fails to produce significant current on a shielded cable could indicate a shield termination problem and detecting that during test could prevent the continuation of testing with a defective test article configuration. These skills support career advancement if desired, with a broad knowledge to develop test methods that do not fit into the generic mold. Be curious and feed that curiosity, read and translate into terms you understand, find a mentor – they learn from your questions.
Q: You mentioned the wind turbine issue caused by the radar – How did you discover that as the cause?
A: It started by asking the site team questions about the problem, reviewing the operation manuals of the turbine, and google maps earth view of the site showed a bubble – that led to finding out what the bubble was. Research frequency and power information so I took some equipment to the site and was able to measure the emitted signal at ground level and at the turbine hub finding less than 0.5 V/m at ground level and over 20 V/m in the hub. The review of the manuals allowed me to identify a vulnerable circuit and measurements confirmed the theory. A couple of days studying to system, a couple of days on-site to make measurements and sketch a temporary fix that the site team could install to make sure that the theory was correct and once confirmed, work with the product designers on the permanent solution to make sure that the solution was compatible with the operational requirements and environmental conditions.
Q: You discussed that the EMC engineer fits into every aspect of the product development – can you add some information on how EMC fits into manufacturing support?
A: I get these kinds of questions a lot. A mechanical engineer thinks that EMC is electrical but fails to consider the impact of shielding, locating filters, and the like. Manufacturing runs into issues that depending on resolution affects the EMC control measures. Installation of a conductive gasket is glued on to retain it until the chassis is closed – manufacturing sees an adhesive but EMC sees conductivity; EMC identifies a component that happens to be round but manufacturing needs a flat surface for placement tools. The EMC engineer needs to understand factory processes to identify and produce compatibility and provide support to all disciplines. I mentioned that a company went from 25% to 95% compliance at the first test. This involved education to the entire company on why EMC is necessary and how they fit into making it work. They also need to know where help can be obtained – advertise yourself as an available asset.
Q: Discuss a product or design for “sniffing” an assembly for low-frequency emissions (below 100 MHz). Loop antenna design, or? Sorry, not sure if this fits with the intent of this discussion.
A: Lots of field probe kits are available from a variety of manufacturers that focus on magnetic field loops and electric field probes. Home-made probes are also versatile – Ken Wyatt has several videos showing DIY tolls that work well – just Google Ken Wyatt EMC and I’m sure you will find his website where a lot of information is available, along with several YouTube videos.
Q: Can you please repeat where the reference to the EMC Engineer Role presentation can be found?
A: I assume you are referring to the 2019 IEEE conference paper on Effectively Communicating the EMC Message in Design Teams by San Rotter and Jerry Meyerhoff. It is available at https://ieeexplore.ieee.org/document/8825312.
Q: Is there any platform where any EMC engineer can participate in the formation of EMC standards?
A: Many committees need more participation and welcome volunteers to support standards development. IEEE Technical Committees are listed at https://www.emcs.org/technical-committees.html with contact information to inquire about the committee of your choice.
Q: How can small design enterprises cope with the cost of an EMC engineer?
A: Small companies are challenged by the need for EMC support without having a full-time position filled. Most default to using a consultant to address the needs by establishing a relationship that develops a fundamental knowledge of the products and company processes with the consultant so that the consultant fits into the organization. I currently work with some companies in that role with an open order getting contacted a few times a year as concerns arise on existing products and a bit heavier involvement during new product development.
Q: How can you keep up with EMC challenges in high-speed designs?
A: High speed does challenge EMC control because the higher speed of digital circuits increases the frequency spectrum demand and the potential for interference. The higher speeds bring out the parasitic component characteristics that tend to reduce the effectiveness of control measures. But understanding how the parasitic parameters function, the design can take advantage of those attributes to create controls. We must always remember that current travels in loops and takes the path of least impedance (not always resistance). Note that propagation velocity is different in a field than in a conductor.
Q: How does the knowledge base differ when we compare an EMC test engineer working in a standard facility with the EMC design engineer working in design environment?
A: The knowledge base differs because of the experiences and exposure to the challenges. But the skill development process should try to minimize the difference and become more thoroughly versed. The test engineer gains more insight in test and measurement equipment and the design engineer has awareness of circuits and component limitations. The fundamental knowledge of EMC is necessary for both roles and often in smaller organizations, the EMC engineer covers both roles as well as fitting into supporting the entire organization.
Q: Could you suggest a training facility who can give the best in the industry, especially in electronics and PCB designing? And Pls suggest a best book in market.
A: I like this question and I did not pay to have this asked. I (Compliance Direction) provide training courses on EMC design and testing customized for specific requests and also through open enrollment currently on MIL-STD-461 / DO-160 testing. Other courses can be made available based on requests. Ken Wyatt (EMC-Seminars) offers several courses each year teaming with other specialists to broaden the scope of training. Applied Technology Institute (ATICourses.com) offers an array of courses on various subjects by a lot of instructors. Also, note that many universities have EMC seminars on a frequent basis.
Q: Is there a rule of thumb for decoupling?
A: Decoupling should be selected for the circuit instead of blindly placing some generic value, but we generally select a fixed value and then solve problems. Placement is key, distribute to minimize trace lengths and the associated inductance. Use bulk capacitance as much as possible through good PCB layer positions. Bruce Archambeault has a lot of work in this arena – his PCB Layout book provides a lot of good information.
Q: I know a book on EMC testing by Mark Montrose. It was written in 2004. Is there any book written in more recent years?
A: David Weston’s Electromagnetic Compatibility, Methods, Analysis, Circuits and Measurement (3rd Edition in 2017) is a good current reference.