My old colleague and good friend Tim Williams sent me the story below for inclusion in EMI Stories/Banana Skins, and I found it so interesting in so many ways that I decided to publish it as a Blog. In so very many EMC standards and other meetings on EMC, we hear that the stability of the AC mains power frequency is either ‘not an EMC issue’ or is ‘never a real EMC … [Read more...]
MIL-STD-461G Implications with RE102 Changes
Introduction: MIL-STD-461G was issued in December 2015 incorporating many changes throughout the document prompting user questions or interpretations. Laboratory situations arise where the generic guidance requires specific situational decisions and the most common tests such as RE102 are included. The user quickly realizes that the given direction does not make sense for a … [Read more...]
Mains Harmonic Current Emissions are Always Bad – It is Risky to Rely on the Limits or Exclusions in the Standards
Many (perhaps all) of EMC standards that are listed under the EMC Directive, that set limits for mains harmonic emissions, have exclusions (‘let-outs’) for certain types of equipment, especially: (these examples are from IEC/EN 61000-3-2 Ed.5:2018) Lighting equipment with a rated power of less than but not equal to 5W Equipment with a rated power of 75W or less, e.g. … [Read more...]
EMC Confidence Checking
I was recently working with a manufacturer of stand-alone ticket machines, who had big problems with Ethernet-related emissions. Long story short – it was the Ethernet hub they had incorporated in their machine. They had assumed that all CE-marked Ethernet hubs would be equally good for EMC, and they had several different types lying around their design department. We tested … [Read more...]
EMC Question for 400Hz Power System
Question: I would appreciate it if you could provide your view / share your expertise on the EMC/EMI protection requirements between the 400Hz Ground Power Systems and the various ICT/ELV installations within an Aircraft. Answer: An interesting and important question! And much too big an issue to be able to deal with comprehensively, in a blog post. The … [Read more...]
Under the Medical Safety Standard IEC 60601-1-1:2014 an EMC Test Lab is not Required to Assess or Review Any Aspect of a Risk Management File
Note: This content was originally posted in January 2020 on emcstandards.co.uk. IEC 60601-1-2:2014 is a medical device safety standard that deals with safety risks that can be caused by electromagnetic interference with electronics. It is not an EMC compliance standard! If the EMC test lab has the necessary safety risk assessment competencies, they could review/assess the … [Read more...]
Functional Safety, Risk Management, EMC and EMI
What is Functional Safety? The safety of products, systems and installations can be split into two parts: i) ‘Basic’ safety: electric shock, excessive temperatures, excessive radiation, fire, explosion, implosion, bruising, pinching, crushing, cutting, emissions of toxic fumes, etc. ii) ‘Functional’ safety: when things being controlled don’t function correctly … [Read more...]
EMC Planning – Key to Success
The following transcript is from Interference Technology’s EMC Live: Mil/Aero event that took place March 2nd, 2021 and covered topics like MIL-STD-461 and RTCA/DO-160 updates, design and testing for harsh environments, and IoT applications in military systems. Good morning, this is Steve Ferguson. I want to say welcome to all the attendees. I'm pleased to speak with … [Read more...]
Effectiveness of a Triaxial Cable Using Pigtails to Terminate the Outer Shield to Chassis Versus a Coaxial Cable With the Shield
Introduction Although it should be well known that the shielding effectiveness of a cable is severely compromised when it is terminated to ground with pigtail/s many equipment manufacturers still use this technique. We see in Reference 1 Figure 7.66 and Table 7.4, Figure 7.80, and Figure 7.102 that the shielding effectiveness of a coaxial cable with pigtail terminations may … [Read more...]
Doing Things That Usually Do Not Work
“If you’re not making mistakes, then you’re not doing anything.” — John Wooden Over the years, I have seen several things that make me scratch my head. Many of them are things I have done (there, I admitted it). I would like to look at these situations to (maybe) help not to make the same mistakes. So, to be clear: Do not do these things. Concerning Shielding One would … [Read more...]
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