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...]
Selection of LC Filters to Ensure HEMP Protection of Electronic Equipment
According to military standards, passive electromagnetic LC filters of HEMP are recommended for use in all kinds of special-purpose electronic equipment. Experience gained by military specialists is usually employed when developing HEMP protection means and measures for civil equipment. Does it make sense to use extremely expensive and bulky HEMP filters for civil equipment? … [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...]
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...]
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...]
Key Points to Remember While Choosing PCB Assembly Company
Once you have designed a PCB and have completed everything that needs to be done before the assembly process, you would require a PCB assembly company to assemble your PCB without any problems. After all, you've been working considerably hard to assemble the layout and the design of the PCB. You would want to be convinced that your PCB gets well-assembled. To ensure that the … [Read more...]
Securing New 5G Physical Assets with Electronic Access Control
The 5G era of mobile computing and communications is rapidly moving forward. 5G stands for the fifth generation of wireless infrastructure—a massive upscale of network technology. It will provide data transfer rates faster than the blink of an eye, reducing latency for even the most data-hungry applications, high bandwidth, and greater opportunities for connectivity and … [Read more...]
A Simple Method for Estimating Radiated Emissions
A simple method for estimating radiated emissions I recently received the following question: How to calculate the radiated E field with following test conditions with an antenna placed 1 meter away from the test setup?: A commercial equipment under test with metal housing Equipment placed on the grounded metallic table/plane LISN installed (and also placed … [Read more...]
Comparison of PWM VFDs versus Resonant Link Converters – Part 2
In Part 2 of this blog, the harmonic current distortion of a typical Variable Frequency Drive (VFD) is discussed, as well the possible solutions to the problems that this causes. Active Front End or (AFE) units are also discussed and some of the issues that they themselves … [Read more...]
Comparison of PWM VFDs versus Resonant Link Converters – Part 1
AC variable frequency drives (VFDs) have been in existence in a number of forms since the early 1970s. In the early 1980s the “pulse width modulated” (PMW) VFD versions began to appear. This form of motor control produced less motor rotor and stator harmonic heating and delivered smoother torque control at slow motor speeds. Thirty years on PWM VFDs are still the most … [Read more...]
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