Re: [TCML] RANDTRONICS Transformer

[David Speck <dave@xxxxxxxxxxxxxxxx>]

Greg,

A rough calculation of power handling ability of a typical laminated 
silicon steel magnetic transformer can be obtained from the formula:

Area [sq in] = 0.16 * SQRT(VA)

otherwise expressed as:

(Area [sq In.] / 0.16) ^ 2 = VA (volt-amps)

Your dimensions work out to about 3415 VA, a respectable size transformer. 

The big problem would be disassembling the unit without damaging the 
laminations too much.  They are likely either welded or varnished 
together, and separating them without bending them is challenging.  For 
best results, they need to flat and compact again in the new assembly. 

You would want to keep the original bobbin intact, or you will have to 
make a new one to receive the new windings before you reassemble your 
new project.

Good luck!

Dave

G Hunter wrote:
> I'm in possession of an unknown transformer, and I'm trying to figure out what to do with it.  It is marked "RANDTRONICS 143A00379".  It has eight taps--four identical taps on each side.  I can't see the windings, as they are covered in stiff, black paper.
>
> The tranny weighs 47 Lbs.  It is an E I core of laminated iron, held together with four bolts thru the corners.  The center leg measures 2.625" x 3.56" for 9.35" of cross-sectional area.  The whole core is 7.5"W, 6.25"H, and 3.56"D.  The winding windows are 1.25"W x 3.75"H.
>
> I have two ideas for it.  Idea #1 is to rewind the thing for high voltage.  I have several pounds of #28 magnet wire for the secondary.  How much power can such a core process?  I'm guessing at least 2kW continuously, and perhaps twice that intermittently.
>
> Idea #2 is to rewind it as a variable ballast for my 11kV pole transformer.  I could wind it with #8 THHN wire, and use an adjustable gap between the E and I pieces for current control.  I wonder how many amps such a core can cope with before saturation?
>
> If anyone has a better guess as to the power handling capacity of such a core, please share.  Also, if you know what kind of tranny this is, please let me know.  I'd hate to cut the windings off something useful.
>
> Cheers,
>
> Greg
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