All - I've been following this discussion and, honestly, I don't see where the problem lies. §2.4.2 is pretty clear, in the context of the standard. Each paragraph stands alone (none are dotted or dashed). In the overall structure of §2.4.2, neither OR nor AND strictly applies: the conditions for applicability are contained within the individual paragraphs.
I would agree that it would be nice and certainly couldn't hurt to have something akin to what §1.2, first paragraph, has for r.m.s., written in to clarify sinusoidal -v- nonsinusoidal. However, consider that everywhere 60950-1 intends to differentiate between sinusoidal and nonsinusoidal waveforms, it explicitly states so. See §1.4.7, Table 2A, Condition 1 to Table 2B, Condition 1 to Table 2C, the second subcolumn under the first major column of Table 2H, the second dashed paragraph of §2.10.3.3 (this is the kind of thing I'm sure Clif wished was in §2.4.2), etc. In sum, if a requirement in 60950-1 doesn't say sinusoidal, it means any waveform, by extension nonsinusoidal. If we step through §2.4.2 paragraph by paragraph, what applies and what doesn't becomes clear. If you have the s/w or don't mind drawing a flow chart by hand, you can create a decision tree, which I have found very useful in working through some standards. In Clif's case, the frequency is under 1kHz, so the first paragraph applies, but the second doesn't. [If the current exceeds the indicated limit, the circuit can not be considered a LCC, but using each available test method could be useful, since Annex D test instruments have some time constants that can shave off contributions to peaks from high frequencies.] Skipping alternative test methods, because Clif's voltage is below 450V the fourth paragraph applies and the fifth and sixth don't. Regards, Peter L. Tarver, PE [email protected] > From: Clif Brick > Sent: Wednesday, November 01, 2006 6:47 AM > > Greetings all, > > under 60950:2001, 2.4.2 limits, under limited current circuits... > > If a device exceeds .7mA peak into 2kohms, is it still > acceptable, under 60950, if the signal is non sinusoidal and > has a circuit capcitance less than .1uF and a voltage under 450V peak? > > I calculate my equivelant circuit capacitance at .03uF, the > output is from a flyback inductor. > > My device has an equivelant stored charge of about 10uC, and > repeats this charge/discharge cycle about every 5.3mS/188.7Hz. > > My question is one of understanding whether or not I must AND > or OR the seperate clauses in 2.4.2. > > Any assistance is appreciated. > > Best regards, > > Clif > > Clifton Brick > Compliance, Safety and Patent Engineer > Invisible Technologies, Inc. > 1000 Fuller Drive > Garrett, IN 46738 > Phone 260-467-5139 > Fax 260-467-5103 > CONFIDENTIALITY This e-mail message and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail message, you are hereby notified that any dissemination, distribution or copying of this e-mail message, and any attachments thereto, is strictly prohibited. If you have received this e-mail message in error, please immediately notify the sender and permanently delete the original and any copies of this email and any prints thereof. ABSENT AN EXPRESS STATEMENT TO THE CONTRARY HEREINABOVE, THIS E-MAIL IS NOT INTENDED AS A SUBSTITUTE FOR A WRITING. Notwithstanding the Uniform Electronic Transactions Act or the applicability of any other law of similar substance and effect, absent an express statement to the contrary hereinabove, this e-mail message its contents, and any attachments hereto are not intended to represent an offer or acceptance to enter into a contract and are not otherwise intended to bind the sender, Sanmina-SCI Corporation (or any of its subsidiaries), or any other person or entity. _____________________________________________________________________________ Scanned by Sanmina-SCI eShield _______ _____________________________________________________________________ - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
