> And a bit of hard won experience. Avoid "no-clean" flux, it will leak at > high humidity. It is only to be used at less than 100 V. > > Regards, > --Paul >
I've measured no-clean flux leakage variance with voltages as low as 2v. It was a regulated supply for a battery powered project & the no-clean flux was conducting a number of pico-amps which varied from day-day. I was only able to solve the problem after "massive" number of cleaning & scrubbing cycles. Even with visual analysis with a microscope, you could not tell the difference before & after the cleaning, and yet, there was a significant measureable difference in effect. ______________________ Brian Guralnick Vergent Technologies Inc. 438 Brahms Ave. Dollard Des Ormeaux Quebec, Canada H9G 2S6 (514) 624-4003 [EMAIL PROTECTED] ----- Original Message ----- From: "Paul Heilman" <[EMAIL PROTECTED]> To: "Protel EDA Discussion List" <[email protected]> Sent: Wednesday, December 13, 2006 5:40 PM Subject: Re: [PEDA] 500V power supply > And a bit of hard won experience. Avoid "no-clean" flux, it will leak at > high humidity. It is only to be used at less than 100 V. > > Regards, > --Paul > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > On Behalf Of [EMAIL PROTECTED] > Sent: Wednesday, December 13, 2006 2:11 PM > To: [email protected] > Subject: Re: [PEDA] 500V power supply > > Oh, come on...Electrical leakage is leakage Brad. Creepage is a "cute" > term meant to apply specifically to surface leakage, but it's all > leakage, as in electrical current flowing unexpectedly through a > dielectric medium. (call it over if you like, it's still "thru" to my > physics eye.) That's one of the novel things that the IPC brings to the > table. Redefinition of basic physics into terms that can suit the > purposes of obsfucation...and of course profit by intellectual ownership > of originally US-citizen-owned information. > > For instance, when I designed an instrument for KLM a couple years ago > to (amongst other things) measure LEAKAGE from pin to pin on a > connector, the mode of transport under consideration was not leakage > across the air gap, but through the dielectric separating the contacts. > > It's my policy to leave the cute to the IPC, Altium's marketing > Goo-Roos, and the cabal of "shhhhh...don't tell anyone its just water". > > And yes, DC or AC, the critical value is the peak value. All AC is DC if > time passes slowly enough, and most DC is AC if you speed the clock a > bit. Peak values Carlos. That means not only what you expect, but what > might be. (Hence the engineering margins I spoke of earlier) > > Regards, > > aj >>-----Original Message----- >>From: [EMAIL PROTECTED] >>[mailto:[EMAIL PROTECTED] On Behalf Of Brad Velander >>Sent: Wednesday, December 13, 2006 4:37 PM >>To: Protel EDA Discussion List >>Subject: Re: [PEDA] 500V power supply >> >> I don't believe I have seen anyone else point out that the > spacing >>requirements are typically specified for DC (RMS). >>Any AC, pulses or spikes have to be suitably considered at their "peak" > >>values. That 'typically' bumps you up at least one voltage >>rating/spacing category. >> >> I would say that you really need to read IPC-2221 section 6.3, > as a >>minimum. >> >> Besides that there is a lot of other information from safety >>regulators like UL/CSA/EU/TUV, more specifically towards product safety > >>and power supply design. With the safety regulators it typically gets >>even more complex because they start taking into account environmental >>pollutants (humidity, dust or other particles which can compromise the >>spacing) and applying pollutant/environment categories. Andrew mentions > >>"leakage" and leakage has two forms. Leakage is typically through air >>or an air gap, "creepage" is across surfaces and is equally important >>in most cases. >> >>Sincerely, >>Brad Velander >>Senior PCB Designer >>Northern Airborne Technology >>#14 - 1925 Kirschner Road, >>Kelowna, BC, V1Y 4N7. >>tel (250) 763-2232 ext. 225 >>fax (250) 762-3374 >> >> >>-----Original Message----- >>From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] >>Sent: Wednesday, December 13, 2006 1:15 PM >>To: [email protected] >>Subject: Re: [PEDA] 500V power supply >> >> >>Exactly. Be careful that you don't think "ideally". Think instead >>cautiously. Cautious is wider spacing. Do not go under, as you will not > >>necessarily see any immediate problem, even though there may very well >>be a major problem. (leakage) >> >> >> >>____________________________________________________________ >>You are subscribed to the PEDA discussion forum >> >>To Post messages: >>mailto:[email protected] >> >>Unsubscribe and Other Options: >>http://techservinc.com/mailman/listinfo/peda_techservinc.com >> >>Browse or Search Old Archives (2001-2004): >>http://www.mail-archive.com/[email protected] >> >>Browse or Search Current Archives (2004-Current): >>http://www.mail-archive.com/[email protected] >> >> > > > This e-mail transmission and its attachments may contain information > from Avtron Manufacturing, Inc. that is proprietary, privileged and/or > confidential and is intended exclusively for the person(s) to whom it is > addressed. Any use, copying, retention or disclosure by any person other > than the intended recipient or the intended recipient's designees is > strictly prohibited. If you have received this message in error, please > notify the sender immediately by return e-mail and delete all copies. > > > ____________________________________________________________ > You are subscribed to the PEDA discussion forum > > To Post messages: > mailto:[email protected] > > Unsubscribe and Other Options: > http://techservinc.com/mailman/listinfo/peda_techservinc.com > > Browse or Search Old Archives (2001-2004): > http://www.mail-archive.com/[email protected] > > Browse or Search Current Archives (2004-Current): > http://www.mail-archive.com/[email protected] > > > > ____________________________________________________________ > You are subscribed to the PEDA discussion forum > > To Post messages: > mailto:[email protected] > > Unsubscribe and Other Options: > http://techservinc.com/mailman/listinfo/peda_techservinc.com > > Browse or Search Old Archives (2001-2004): > http://www.mail-archive.com/[email protected] > > Browse or Search Current Archives (2004-Current): > http://www.mail-archive.com/[email protected] ____________________________________________________________ You are subscribed to the PEDA discussion forum To Post messages: mailto:[email protected] Unsubscribe and Other Options: http://techservinc.com/mailman/listinfo/peda_techservinc.com Browse or Search Old Archives (2001-2004): http://www.mail-archive.com/[email protected] Browse or Search Current Archives (2004-Current): http://www.mail-archive.com/[email protected]
