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&spn=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] ______________________________________________________________________