VFD And Radiated EMC

[sreid]

In recent threads, EN61800-3 has been said to allowed different categories of radiated emissions. Could someone give a brief summary of the categories and the levels of radiated emissions allowed.

 

[Valvecrazy]

Quote
"As the demand for electricity has increased, more and more current has been released into the environment. That's bad enough. It gets much, much worse. The advent of computers, variable speed motors and a variety of other types of equipment, including many that conserve energy, created what's often called "dirty electricity." This equipment distorts the "clean" current, creating resulting in electricity that's at much higher frequencies. The higher the frequency, the lower the capacity of wires, which means even more return electricity spills into the environment. And the higher the frequency, the more harmful its biological effects."

Here are a couple of links that might help;

http://www.familyfarmdefenders.org/pmwiki.php/Publications/StrayVoltage-AnUnrecognizedHealthHazard

http://www.strayvoltage.org/

 

[ozmosis]

sreid
Under EN61800-3, the radiated levels typically fall under the standards:
EN 55011 Class A1
EN 55011 Class B
Class B has the more severe levels of radiated emission and is typically used in environments classed as "Residential, Domestic and light Industrial", more tpically we would say this is LV networks with different users on a shared public supply.
Class A1 is typically Industrial environments where a user has ownership of their own transformer to the public network.

For Conducted levels these follow similar standards and fall into the same brackets.
EN61800-3 now defines these categories as:
C1: Domestic, Res and Light industry where the user has no knowledge of EMC and therefore demands a product that can be simply "plugged in": Unrestricted Distribution
C2: Domestic, Res... but the user has some knowledge of EMC issues and will be able to follow guidelines provided by the supplier of the drive. Restricted distribution
C3: Industrial Environment. User has knowledge of EMC etc. Restricted distribution.

There is a lot more to it than this but I think you get the idea.

 

[sreid]

Let me elaborate on my question. 10 years ago when I was involved in CE testing equipment, there were no requirements that were difficult to pass except radiated emissions. At that time there was one spec and it was 10 microvolts per meter from "DC to Daylight." In a city, comercial AM and FM radio signal levels will exceed that.

So I happy to see that the EMC directives now recognize that the radiation level requirements should match the application. Since we build industrial equipment that is used in an industrial environment, I was most interested in the least restrictive present requirement without buying the new spec (and all the related specs that are referenced).