Midnight Musings from Roxburgh EMC's Product Manager
EMC expert Tom Downing ponders the challenges of RFI (Radio Frequency Interference) in the home.
"As Product Manager at Roxburgh EMC, I am the person that usually responds, in the first instance, to incoming technical queries relating to conducted emissions and immunity. Whilst it would be wonderful to report that I spend my days discussing earth leakage with the world’s most pre-eminent inverter manufacturers or voltage ratings with renewable energy companies it is fair to say that not all communications are linked to volume opportunities.
"As one of a handful of UK based filter manufacturers we also receive our fair share of queries from private individuals looking for some friendly advice from a local specialist. These queries often relate to WiFi signals becoming interrupted by a variety of types of equipment including running machines, electric gates and fish pond pumps. I possibly spend longer on these calls than my managers would appreciate but it is always rewarding to help find a solution and frustrating when despite our best efforts the problem remains. Lately though I have encountered a more concerning interference issue; especially as it affects me. I have a relatively new hard wired smoke alarm system that sounds spuriously at odd times of the day. One of our callers who had the same problem had observed that his new fridge freezer would sometimes set off his similar smoke alarm when the compressor turns off. This was solved by the addition of a small EMC filter thus providing reasonable evidence that the issue was caused by a conducted emissions problem.
"I pondered this recently as I went to turn off my smoke alarm in the middle of the night when I realised that I had not troubled myself to check for a fire – I had assumed this alarm was spurious like all of the others. This in turn reminded me of the importance of the European (EMC) Directive 2014/30/EU and the companies that diligently work to meet or exceed the standards that are relevant to their products. I am not intending to imply that my fridge is non-compliant nor that the directive is too lenient – just that it is important that in this world of increasingly complex and pervasive electronics that we should keep in mind the real, possible human consequences of RFI.
"At Roxburgh EMC we have an extensive pre-compliance laboratory. All equipment is calibrated and we can provide a test report. Some of our customers add our test report to their technical file as evidence of due diligence for their self-certification. Others use our service to confirm that their equipment will pass before they engage the services of a competent body. Our test engineers are also competent in design so will often create a new filter to meet with specific mounting, dimensional, performance and earth leakage constraints."
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