CE conformity to EMC directive
CE conformity to EMC directive
(OP)
We are OEM company. In the equipment we make we are using drives, which are carring CE mark on them. Drive manufacturer has EC declaration of conformity of these drives to the european directives. These are 480VAC, 7amp and 10amp input rating drives.
My question is about EMC directive. What happen to the emission level, when several drives are used on the machine? Does it add up? Drives are operating simultineously.
Does machine as a unit need to be tested if it is conforms to the EMC directive.
Thank you.
Paul.
My question is about EMC directive. What happen to the emission level, when several drives are used on the machine? Does it add up? Drives are operating simultineously.
Does machine as a unit need to be tested if it is conforms to the EMC directive.
Thank you.
Paul.





RE: CE conformity to EMC directive
That means that two drives with EMI level X generates sqrt(X) total emission. Four identical drives generate twice as much as a single drive.
If your level is in dB, it is a lot simpler. If one drive has EMI level Y dBuV, then two drives have Y+3 dBuV and four drives have y+6 dBuV etcetera.
Yes, if you have a machine with several drives, you need to verify the EMI level of the complete machine at the PCC (the connection to the grid) when the machine is running.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: CE conformity to EMC directive
Paul.
RE: CE conformity to EMC directive
So, having CE on the drive does not mean it complies with the EMC directive. It has to be installed (as the manf advises) to the specific environment your customer is requiring. Loosely: C1 is the highest level and requires Class B filters and screened cable and will have limits on cable lengths subject to what the VFD manf advises. C2 is slightly lower emissions (Filter class A1) but still governed by what the manf advises on cable legths etc. It goes on. Your VFD supplier should be able to advise. If they don't, get another one.
Hope this helps and not hinders.
RE: CE conformity to EMC directive
product "are in conformity with provisions of the following EC Directive(s) when installed in accordance with the installation instructions contained in the product documentation:
..............
89/336/EEC EMC Directive as amended by 92/31/EEC and 93/68/EEC."
The specification in the user manual is more descriptive:
"Marked for all applicable European Directive
EMC Directive (89/336/EEC)
Emissions
EN61800-3 Adjustable Speed electrical power drive systems
Part 3
Immunity
EN61800-3 Second Environment , Restricted Distribution
RE: CE conformity to EMC directive
2nd Environment is basically looking at C3 classification whereby the connection is more "industrial", i.e. isolated from the public network by a transformer (typically). If the machine you supply goes into the public, residential or light industrial environment, then you might need higher levels of filtering than the 'standard' supplied with the drive. Maybe C1 or C2 environemnt requiring Class A1 or even Class B filters.
Most people don't bother checking and get away with it but if you are doing it right, you need to understand both the environments your products will be going into and then the restrictions the VFD supplier will impose to allow compliance.
There isn't just one solution to complying with the EMC Directive for drives (EN61800-3), it really does depend on the installation environment. The greater chance the electrical system has of polluting the public electrical network, the higher the level of filtering is needed. The higher the level of filtering, the tighter controls on the installation and (usually) the cable lengths.
And another thing, EMC Directive is not just high frequency interference (RFI) it also covers Low frequency interference too (harmonics). If you are supplying this drive into a Public/residential/light industrial (i.e.shared power system) then the harmonic product standards will come into play, especially for the current rating of the drive you have indicated. EN61000-3-2 is the standard for products <16A, so be mindful of this.
RE: CE conformity to EMC directive
If in declaration of conformity we'll specify that equipment is in conformance with EMC requirement for industrial environment (basically what is drive manufacturer did) is it OK? This way responsibility is put on end user.
RE: CE conformity to EMC directive
The former EMC Directive came into force on 1st January 1992, and replaced all existing legislation for electrical and electronic equipment concerned, including fixed installations, from 1st January 1996. It has been subject to three amendments (see also Revision of the EMC Directive) and it has been repealed by the new 2004/108/EC Directive as from 20th July 2007.
Shouldn't any new OEM equiptment be to the latest directive?
I do not have a copy so I can not compare any differences
RE: CE conformity to EMC directive
Yes, that is one of the problems you would be faced with.
The basis of the standard is "you shall not pollute electrically the network of any other person connected to this supply". This is as far as emissions are concerned. This is where the apples-apples comes in. If you are in a steel plant and you turn a 3hp VFD on, the chances of Doris sat at home a mile away having her favourite television program interfered with will be slim if not at all. However, if her next door neighbour installed a 20Hp VFD on the same network as Doris on his lathe and switched it on, there could be a posssibility of intereference if the VFD has the same sort of filtering as it would in the steel plant. The EMC Directive is there to protect 'other users' but with the necessary level of filtering for the environment it will be installed into. In basic terms, the standard is not too bothered what happens inside the steel plant as long as it doesn't get into the public domain. However, a sensible approach is always needed to ensure you protect the integrity of your own machines to ensure they operate correctly. This is outside the EMC DIrective but possible to 'use' it to ensure good practice.
The levels of filtering are all laid out subject to the sensitivity of the environment it will be going into.
I'm afraid that in your case, the responsibility rests with you to know where the machine will be going. If it is "industrial" then you could look at certain levels of filtering to suit that environment and different for "public, Residential and Light Industrial" :typically meaning the site is on a shared LV distribution network.
Difficult when you're (I guess) in the USA and your end customer could be on the Isle of Skye.