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October 2013

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Subject:
From:
Ed Popielarski <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Ed Popielarski <[log in to unmask]>
Date:
Thu, 31 Oct 2013 15:07:13 +0000
Content-Type:
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text/plain (69 lines)
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
> 
> 
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> ______________________________________________________________________

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