Josh and Ian, The discontinuous interference referred to by Ian is commonly referred to as click noise and can be applied to short term line-conducted emissions of Class B products. Not to be applied to radiated emissions (which is not a requirement in EN 55014(-1)). It is referred to EN 61326-1 as I mentioned above in Table 4.
I may indicate compliance with a standard if I am below the limit and within the measurement uncertainty, but I would never indicate compliance when above the limit regardless of where the margin is compared to the measurement uncertainty. I do not know of any limit relaxation for environment or duty cycle for this situation. Class A is the appropriate level for industrial environments. Sorry I could not be of more assistance. Michael Peters, NCE From: [email protected] [mailto:[email protected]]On Behalf Of Gordon,Ian Sent: Tuesday, March 22, 2005 3:42 AM To: '[email protected]'; EMC-PSTC Subject: RE: EN 61326-1 question Josh Although not referred to in EN61326 can you apply EN55014-1 to your product? This provides for assessment of discontinuous interference. Scope of EN 55014-1: ELECTROMAGNETIC COMPATIBILITY - REQUIREMENTS FOR HOUSEHOLD APPLIANCES, ELECTRIC TOOLS AND SIMILAR APPARATUS - Part 1: Emission 1 Scope 1.1 This standard applies to the conduction and the radiation of radio-frequency disturbances >from appliances whose main functions are performed by motors and switching or regulating devices, unless the r.f. energy is intentionally generated or intended for illumination. It includes such equipment as: household electrical appliances, electric tools, regulating controls using semiconductor devices, motor-driven electro-medical apparatus, !electric/electronic toys", automatic dispensing machines as well as cine or slide projectors. © BSI 14 July 2003 Furthermore, does the margin of 1-2dB over the limit line to which you refer to take into consideration the measurement uncertainties associated with the test? If not then the following may apply (taken from section 4.6.1 of UKAS document LAB34): "The measured result is above (below) the specification limit by a margin less than the measurement uncertainty; it is therefore not possible to state compliance based on the 95% level of confidence. However, the result indicates that compliance (non-compliance) is more probable than non-compliance (compliance) with the specification limit." Ian Gordon > -----Original Message----- > From: Josh Wiseman [mailto:[email protected]] > Sent: 21 March 2005 16:42 > To: EMC-PSTC > Subject: EN 61326-1 question > > > All, > > I have been testing a clients unit that uses a universal AC > motor. The > unit is intended to operate for 5-10 minutes and be idle for > 30 minutes > up to several hours before it is operated again. > > The unit currently will not meet the Class A radiated emissions limit, > the QP value is 1-2 dB over the limit around 45 MHz. Since > this unit is > meant for industrial environments I am curious if there is something > that would allow this emission based on the duration of use. > > Thanks in advance for the help. > Josh > -- > Josh Wiseman > Owner, A2Z Compliance > CE Lab Manager, L F Research > *********************************************************************** The information contained in this email and any attachments may be confidential and is provided solely for the use of the intended recipient(s). If you are not the intended recipient, you are hereby notified that any disclosure, distribution, or use of this e-mail, its attachments or any information contained therein is unauthorised and prohibited. If you have received this in error, please contact the sender immediately and delete this e-mail and any attachments. No responsibility is accepted for any virus or defect that might arise from opening this e-mail or attachments, whether or not it has been checked by anti-virus software. 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