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...]
Insertion Loss and Filter Performance
Background Filters are almost always a part of electronics design. Design engineers design a filter to achieve certain attenuation in specified frequency range. There are many types of filters, such as high pass, low pass or bandwidth. Popular filter configurations include L-C, C-L-C (π) or L-C- L (T). It is safe to say that when it comes to filter design, the discussion of … [Read more...]
For Remote Patient Monitoring Systems, Wireless Coexistence Can Be Lifesaving
The demand for wireless medical applications such as remote patient monitoring, real-time diagnostic analysis, smart surgical systems, and implantable sensors have grown significantly over the last couple of years. Thanks to implanted medical devices, many patients live an almost normal life without having their mobility compromised. Popular implants include cardiac pacemakers, … [Read more...]
Instrument Hardware to Ensure Accurate Measurements Using NFPA 5lb Weights for ESD Control
Authored by: Gene S. Monroe, iNCE, NASA Langley Research Center, Hampton, VA Bob Vermillion, CPP, Fellow, iNCE, RMV Technology Group, LLC, NASA Ames Research Center, CA INTRODUCTION Proper verification of an Electrostatic Discharge (ESD) Protected Area (EPA) relies heavily on the use of the National Fire Protection Association (NFPA) 5lb weights. These 5lb weights … [Read more...]
Thermoplastic Faraday Cage: Specialty Polymers for Inherent EMI Shielding of Medical Devices
Co-Authors: Leen-Pieter Deurloo | Martin Sas, Ph.D. | Marnik Vaes Today's electronics can generate strong electromagnetic interference (EMI) that may affect electromagnetic compatibility (EMC) and, as a result, impact device performance. Polymer compounds with integrated electrical conductivity offer a potential solution to resolve EMI and electrostatic discharge … [Read more...]
Don’t Rely on the Stability of the Mains Frequency
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...]
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...]
- « Previous Page
- 1
- 2
- 3
- 4
- 5
- …
- 66
- Next Page »
