Standard_Drives_Guide

Industry White Papers Europe and the CE Marking: Questions and Answers

(continued from previous page) Clearly the low voltage directive does apply to virtually all low voltage adjustable speed drives on the market today. One point of confusion regarding the low voltage directive is that it has been in existence since 1973, however, conformance to the direc- tive was not indicated by affixing of the CE marking to either the product or its packaging. Per Article 13 of 93/68/EEC, however, the low voltage directive was amended to require that manufac- turers issue an EC Declaration of Conformity to the EN standards applicable to their product and affix the CE marking as a visible indication of the declaration. Q: What are the approved standards (ENs) for which a presumption of compliance can be conferred for adjustable speed drives? A: CENELEC has directed the International Electrotechnical Commission (usually referred to as the IEC) to develop standards for ac and dc drive systems which they can then adopt and pub- lish as European norms (ENs). The IEC has two working groups of SC22G, a technical subcommittee which focuses on the genera- tion of standards for semiconductor power converters for adjustable speed drive systems, dedicated to developing two new standards: General Purpose Low Voltage Adjustable Frequency AC Power Drive Systems General Purpose Adjustable Speed DC Power Drive Systems The following ENs typically apply to variable speed drives: EN50178 - Electronic equipment for use in power installations EN55011 - Emissions from industrial, scientific, and medical (ISM) equipment EM61800 - Adjustable speed electrical power drive systems Q: What is some background information on the EMC directive? A: EMC is short for electromagnetic compatibility. In the United States, the Federal Communications Commission (FCC) has the authority to regulate most commercially available products for emissions and immunity to electromagnetic interference, and since 1983 has done so through FCC Rule 15 Subpart J and other rules. This implementation of limits is primarily aimed at products for the residential and commercial marketplaces and not the industrial marketplace. In cases where interference does occur, either mitigating methods must be employed by the offender, or the user may simply choose to relocate the equipment until interference is within acceptable levels. Not surprisingly, due to its background, the FCC regulations have been restricted to the category traditionally referred to as RFI, or radio frequency interference (450 kHz for conducted and 30 mHz for radiated emissions). Starting 3 May 1989, the European Union took a much more aggressive stance in regulating electromagnetic interference issues than has been done in the United States. Led by the Germans, who have historically had strong electromagnetic interference laws, the European Council issued Directive 89/336/EEC, which has become commonly known as the EMC directive. This directive is more far reaching than RFI limits, such as FCC Rule 15, in that a vast range of electrical appliances and equipment, including those intended for the industrial environ-

ment, falls within its scope. In addition, the scope of the EMC directive is being redefined within the context of the IEC to include topics that historically have been referred to as power quality issues such as harmonics, waveform notching, susceptibil- ity to electrostatic discharge, and the like. This is largely due to the fact that the IEC technical committee, which specializes in electromagnetic compatibility issues, is dominated by representa- tives of power companies. The 89/336/EEC directive required mandatory compliance by 1 January 1992, however, it was realized that the wide scope of the directive demonstrated the overriding need to provide for a substantial transitional period to allow for changeover from the national-based systems to the new exclusive EU system. Therefore, on 28 April 1992, the council adopted Directive 92/31/EEC, which allowed a transitional period until 31 December 1995. Q: What does the EMC directive actually say? A: Like most directives, the EMC directive is not highly technical in nature, but rather attempts first to define its scope and then to state essential requirements such as the following which can be found in Article 4: “The apparatus within the scope of the directive are to be so constructed that: a) the electromagnetic disturbance it generates does not exceed a level allowing radio and telecommunications equip- ment and other apparatus to operate as intended; b) the apparatus has an adequate level of intrinsic-immunity to electromagnetic disturbance to enable it to operate as intended.” The protection requirements of the directive are therefore laid down in terms of objectives, while the limit values and methods of measurement must be given in the harmonized standards (European norms or ENs). To develop the ENs, the EU’s elec- trotechnical standard-making body (CENELEC) reached a cooper- ative agreement with the IEC. The remainder of the directive is dedicated to describing the various methods by which compli- ance with the directive can be achieved, of which there can be several depending on the product involved. Products that issue a declaration of conformity to Directive 89/336/EEC will clearly indicate the conditions required for compliance. These conditions may include items such as filters and special wiring and ground- ing procedures. Q: What is the cooperative agreement between CENELEC and the IEC? A: This agreement stipulates that the IEC has the primary respon- sibility for developing electrotechnical standards. These standards can be adopted, with possible amendments, and published by CENELEC as “harmonized” European standards (ENs). When CENELEC has a need for a specific standard, it asks the IEC to develop one. If the EC is not in a position to meet the require- ments of CENELEC (ex. too short of a deadline), CENELEC will develop the standard by itself. In these cases, the IEC may adopt standards prepared in CENELEC, again with possible amend- ments. It is important to realize that although IEC and CENELEC standards will usually be equivalent or similar from a technical point of view, it is actually the ENs issued by CENELEC which are legally binding within the EU due to their role in compliance with applicable directives.

Standard Drives Buyers Guide

www.geindustrial.com

116

Prices and data subject to change without notice