Hi Brian, Thanks for your advice about the use of spray type application!
Regards, Scott > On 27 Feb, 2016, at 1:34 am, Brian O'Connell <[email protected]> wrote: > > Generally agree, but be careful with using a spray-type application for the > accelerant. Prefer to use an eye dropper. Had a tech, while doing tests for > UL5085-3, that caught a small linear transformer on fire because the (very > volatile) accelerant had not completely evaporated after spray application, > and had been applied over a 2x2cm area. > > Thermal paste, by itself, can be adiabatic (may actually expand to insulate), > and is essentially a contaminate unless compressed between two parallel > surfaces. Should never be used around TCs for type tests. Cured cyanoacrylate > is essentially diabatic. > > The glue line must be very thin, and must hold the TC bead in firm, static > mechanical contact with the component. > > Wrote a tutorial about thermal test technique and error sources about 10 > years ago, that showed up at two NRTLs, but was never accepted by the IEEE > PSES. Should be sitting somewhere on one of the servers, will try to find it. > > Of course the best accelerant for TC adhesives are the tears of the sales and > marketing directors. > > Brian > > -----Original Message----- > From: Kunde, Brian [mailto:[email protected]] > Sent: Friday, February 26, 2016 9:13 AM > To: [email protected] > Subject: Re: [PSES] Reliable means to attach thermocouple to object > > Scott, > > Year ago we used Tac Pac with a spray accelerator. Just place a dab of glue > where you want it, insert the thermocouple, then spray it with the > accelerator and it would instantly harden. To remove, we used some kind of > solvent (acetone?). Just a drop would start to soften the glue and within 30 > seconds you could pull the thermocouple out for re-use. > > I don't recall the product numbers but a little research should find them > easy enough. I think it was something like Loctite 444 adhesive with > accelerator kit. The accelerator was 7452 and came either in a small spray > can or in a bottle. There are probably new formulas today that work just as > good. > > Some glue the thermocouple up slightly from the end and then use thermal > paste on the end. It is messy and we didn't really see much difference in > our test results. > > The Other Brian > > > -----Original Message----- > From: Scott Xe [mailto:[email protected]] > Sent: Friday, February 26, 2016 11:53 AM > To: [email protected] > Subject: [PSES] Reliable means to attach thermocouple to object > > I used to attach thermocouple to the object under temperature rise test using > Kapton tape. Currently I looked at an SMPS that is operating at a > temperature of 120 degC under an ambient temperature of 20 degC. The tape > seems not very reliable and rigid enough for long period of testing. Is > there any other more suitable means to attach the thermocouple to such high > temperature point of interest? > > The spec quotes the max temperature of 150 degC. Is it normal for the > rectifier to have such high operating temperature? > > Thanks and regards, > > Scott > > - > ---------------------------------------------------------------- > This message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. To post a message to the list, send your e-mail to > <[email protected]> > > All emc-pstc postings are archived and searchable on the web at: > http://www.ieee-pses.org/emc-pstc.html > > Attachments are not permitted but the IEEE PSES Online Communities site at > http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used > formats), large files, etc. > > Website: http://www.ieee-pses.org/ > Instructions: http://www.ieee-pses.org/list.html (including how to > unsubscribe) > 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]> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) 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]>
