Need help finding information on a Transformer.

MaxHeadRoom

Joined Jul 18, 2013
28,688
Have you enquired of Antec he can build one for you.
Also what of the primary resistance? Open circuit or?
You don't need to have dual primaries if it is custom.
Toroids are very simple to either find and/or modify.
Max.
 

ebp

Joined Feb 8, 2018
2,332
There used to be a few companies that would make custom toroids in low quantity, so it wouldn't surprise me in the slightest if it were a custom. 21 volts certainly isn't common for off-the-shelf transformers. It is also an unusual aspect ratio - height about the same as OD; most std types are lower and larger OD for that power range.

If there is a thermal fuse, it is very likely just under the outermost insulation windings. Putting it anywhere else would make a significant lump in the windings and cause all sorts of annoyances. Since the transformer is already dead, and assuming the primary measures open-circuit, I'd try removing the outer insulation.

An open thermal fuse may have resulted from excessive ambient temp (something preventing cooling airflow over the xfmr), overload, or a shorted turn somewhere in the windings, or possibly prolonged operation at high line voltage (core saturation leading to high temperature). If you find an open fuse & replace it, I recommend powering up the primary with the secondary open, preferably from a variable transformer so you can increase the voltage slowly. Monitor the current in the primary. Typically the magnetizing (no-load) current in toroids is usually pretty low, but I suggest looking for specs for something that weighs about the same to see what is spec'd for magnetizing current. A shorted turn will result in much higher current. If you don't have a variable xfmr, at least use a fuse in series with the primary - maybe a slow-blow around 3A - for some measure of safety.

If it died recently from over-temp, it may still smell burned.

Winding suitable tape to replace the original outer insulation will be rather painful. Glass cloth tape is quite expensive, but often easier to handle than something like polyester transformer tape.

I very strongly advise against repairing it without installing a new thermal fuse of the same characteristics. It is enclosed inside a fuel source with another that is slightly less flammable sitting on top.
 
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