Is it likely that the insulation is reacting with itself, either incorrect cure or a missing hardener / component due to imposed environmental restrictions. I remember working on tape recorders that the tires would just dissolve over time and leave a black sticky mess. pat On Thu, Oct 31, 2013 at 7:07 AM, Ed Popielarski wrote: > NEMA MW82-C Class 180 C > > Ed Popielarski > Engineering Manager > > > 970 NE 21st Ct. > Oak Harbor, Wa. 98277 > > Ph: 360-675-1322 > Fx: 206-624-0965 > Cl: 949-581-6601 > > > https://maps.google.com/maps/myplaces?hl=en&ll=48.315753,-122.643578&spn=0.011188,0.033023&ctz=420&t=m&z=16&iwloc=A > > > -----Original Message----- > From: Don Vischulis [mailto:[log in to unmask]] Sent: Thursday, > October 31, 2013 4:10 AM > To: TechNet E-Mail Forum; Ed Popielarski > Subject: Re: [TN] SMT transformer failures > > Any idea what type insulation is on the magnet wire or the NEMA > designation of the magnet wire? > > Don Vischulis > > Sent from my iPad > >> On Oct 30, 2013, at 12:04 PM, Ed Popielarski >> <[log in to unmask]> wrote: >> >> Good Morning Esteemed Colleagues, >> >> We have recently been experiencing increasing failure rates of an SMT >> (5.2 X 5.2 X 1.2 mm) transformer. The first build in September showed >> about 6% fallout. Subsequent builds from the same reel have increased >> to 25% most recently. These components have been stored in a normal >> ambient environment. I have verified and re-verified reflow >> conditions are well within manufacturer's specifications (confirmed >> by the manufacturer). >> >> When this problem was first identified, I "dissected" one of the >> failing devices and found the wire pair (primary and secondary) in >> good condition on the outer windings, but as I continued to unwind >> down to about 1/3 deep, the insulation began to stick both side by >> side and to subsequent layers which would "fuzz" as it was pulled >> apart with exposed copper implied. >> >> I am beginning to suspect "cold flow", a problem that was prevalent >> in the days of wire wrapped backplanes. >> >> Has anyone experienced a similar condition? The manufacturer has been >> "working on it" since mid-September and has yet to provide any root >> cause and/or solution. >> >> Any insight would be appreciated. >> >> >> Ed Popielarski >> Engineering Manager >> >> [Description: FullLogo] >> 970 NE 21st Ct. >> Oak Harbor, Wa. 98277 >> >> Ph: 360-675-1322 >> Fx: 206-624-0965 >> Cl: 949-581-6601 >> >> >> https://maps.google.com/maps/myplaces?hl=en&ll=48.315753,-122.643578&s >> pn=0.011188,0.033023&ctz=420&t=m&z=16&iwloc=A >> >> >> >> ______________________________________________________________________ >> This email has been scanned by the Symantec Email Security.cloud >> service. >> For more information please contact helpdesk at x2960 or >> [log in to unmask] >> ______________________________________________________________________ > > ______________________________________________________________________ > This email has been scanned by the Symantec Email Security.cloud > service. > For more information please contact helpdesk at x2960 or > [log in to unmask] > ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________