[CJ]

excited to have on the chopping block a fine specimen today,

full props to the Rackmonkey for shipping this out, along with another surprise to be offered up later,

UTC LS-51  Push-Pull to Line    30K: 600   with sec taps

more info>

[CJ]

would you want somebody to use a chain saw on your bad knee or go orthoscopic?

so we use a drill to take off the  burr from the crimp from the lid so we can drain the UTC tar that we know is gonna be in there,

after deburr, heat the can a bit, tap around the can lightly with a hammer, insert small screwdriver between can and lid it will open up like a tin of sardines,

[CJ]

this guy has two primaries, one of them was open,

but we can still measure pri ind on the good one,

here is a Voltage  vs Henries chart at 20 Hz>

[EmRR]

Cool.   

The one I looked at with an Extech 380193 handheld read  2487H :  34H57 at 120Hz.

[CJ]

in a perfect world you would quadruple the inductance of one primary to get full primary inductance, most of the time it runs at about 80% of that figure due to leakage inductance,

we could not get the pri into full saturation at 20 hz with our generator, so we dropped down to 10 Hz which means twice the flux for the same voltage, this resulted in full saturation>

[CJ]

here is Henries vs Frequency for one of the secondaries>

[CJ]

full secondary inductance vs frequency

not as high as we would suspect,  the dead primary might be the reason,

[CJ]

pop the lid and there it is, the infamous black goo,

do not put this on your hamburger, it is not A-1 Steak Sauce.

[CJ]

stick this bad boy outdoors in the toaster oven at 300,  wait about 45 minutes and the gravy is done.

roast it upside down in a pie tin with a stick under one side to drain the goop. we pulled the wrapper while it was hot and have a nice clean core to work with.

i think.

[Gus]

CJ

Does anyone know what the tar like material is?
I wonder if it is toxic?

Found some links
http://messui.polygonal-moogle.com/valves/VR199506.pdf
https://www.vintage-radio.net/forum/showthread.php?t=37381

[shabtek]

I have seen asphalt based compound and ones that likely contained some amount of beeswax

[CJ]

cool links Gus, thanks! i will have to try thr freezer method. 

this book here is the bible on insulating stuff, 600 pages worth>

Handbook of Electrical and Electronic Insulating Materials 2nd Edition


looks like this guy had an HV punch through problem, maybe a hi-pot test gone bad or maybe some RF,  punched a hole from the primary to the core>

[CJ]

or maybe some kind of blunt force trauma at the winding shop>

[CJ]

this transformer uses twin coils on an L core,

the weird copper colored coating is something we have not seen before.

this particular shape is not in the Mag Metals catalog, so we drew it up.

[CJ]

we have two primaries on each coil

secondary is in the middle.

primary runs 240 turns per layer of #38

10 layers per primary, so about 9600 turns give or take, standard UTC turns count.

[CJ]

here is the outer wrapper being taken off,

1/2 inch cloth tape used to stitch down the leads,

have not figured out what the numbered marker tape means,

[CJ]

inner secondary layer got shoved around a bit,

[CJ]

coil/core assy

[CJ]

the inner mu can was proving difficult but we got it.

[EmRR]

wow, that punch through or shop ding is so much more obvious than most failures.

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