UTC LS-51

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

CJ

Well-known member
GDIY Supporter
Joined
Jun 3, 2004
Messages
15,664
Location
California
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>





 

Attachments

  • utc ls.png
    utc ls.png
    789.9 KB · Views: 38
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,
 

Attachments

  • u1.JPG
    u1.JPG
    137.6 KB · Views: 48
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>

 

Attachments

  • LS-51 pri ind vs level.png
    LS-51 pri ind vs level.png
    10.5 KB · Views: 30
Cool. 

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

 

Attachments

  • LS-51 pri ind 10 Hz.png
    LS-51 pri ind 10 Hz.png
    11.2 KB · Views: 31
full secondary inductance vs frequency

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

 

Attachments

  • LS-51  full sec ind vs f.png
    LS-51 full sec ind vs f.png
    9.8 KB · Views: 24
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.

 

Attachments

  • goo.JPG
    goo.JPG
    185 KB · Views: 48
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.

 

Attachments

  • frying  pan.JPG
    frying pan.JPG
    204.8 KB · Views: 59
cool links Gus, thanks! i will have to try thr freezer method.  :D

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>




 

Attachments

  • hole.JPG
    hole.JPG
    184.5 KB · Views: 41
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.
 

Attachments

  • lams.JPG
    lams.JPG
    198.2 KB · Views: 45
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.
 

Attachments

  • c2.JPG
    c2.JPG
    202.5 KB · Views: 27
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,
 

Attachments

  • outer.JPG
    outer.JPG
    178.1 KB · Views: 33

Latest posts

Back
Top