Re: Transformer from a microwave oven

Engineer wrote:
Hi, all...
This may seem an odd post but I'm an avid re-user and recycler of old and/or scrapped electronic stuff (especially tube equipment), so I hope all will be clear...

I have just picked over the carcass of a dead microwave oven (free junk from a church sale) to get a thermal switch to repair our main unit, but that's another story...

I pulled out all the usable bits (not many!) but also the power transformer. It has a 1.75 x 1,25 inch core, weighs 9 1/4 lbs, and is 120 VAC to a scary 1,925 VAC (measured off load.) The core has two magnetic shunts between the windings to give, I think, a degree of voltage regulation (I may be able to press or knock them out, but I've not tried yet.) The 120 volt primary resistance is about 0.3 ohm; the 2 KV secondary is 115 ohms.

Can anyone think of something useful to do with this this transformer. All I can come up with is:

1. Use two of them back to back as a bench isolation transformer (but watch the 2 KV floating around!)
2. Use as the OPT for a weird single-ended tube amplifier with 3.8 Kohm plate impedance (rather low) to a 15 ohm speaker (forget about 8 ohm speakers - too low; also need to isolate the secondary from the frame (easy enough to do).)
3. Use it with a voltage doubler or tripler for an electrostatic filter (would not fit inside most units so serious safety engineering required.) Much too big, though.
4. Run it off a suitable battery and interrupter (NOT AC mains!) to power an electric fence.
5. Use it as a choke in a tube power supply. I'm not sure of the secondary winding inductance or current rating. Again, isolate the secondary.
6. Use to replace another failed one <g> Do they ever fail?

That's it.  Thanks for all ideas.
Cheers,
Roger



http://oak.cats.ohiou.edu/~postr/bapix/813amp.htm
http://repairfaq.ece.drexel.edu/sam/laserasc.htm#ascias
http://repairfaq.cis.upenn.edu/sam/gadget.htm#gadmot

Some ideas on those pages.

Ed
.

Relevant Pages

  • OT: Transformer from a microwave oven
    ... I pulled out all the usable bits but also the power ... The 120 volt primary resistance is about 0.3 ohm; ... Use as the OPT for a weird single-ended tube amplifier with 3.8 ... also need to isolate the secondary from the ...
    (rec.audio.tubes)
  • Re: Transformer from a microwave oven
    ... The 120 volt primary resistance is about 0.3 ohm; ... Use as the OPT for a weird single-ended tube amplifier with 3.8 ... > ohm speakers - too low; also need to isolate the secondary from ... > power an electric fence. ...
    (rec.audio.tubes)
  • Re: Transformer from a microwave oven
    ... Engineer wrote: ... The 120 volt primary resistance is about 0.3 ohm; ... > Can anyone think of something useful to do with this this transformer. ... > ohm speakers - too low; also need to isolate the secondary from the ...
    (sci.electronics.design)
  • Re: OT: Transformer from a microwave oven
    ... Engineer wrote: ... > voltage regulation (I may be able to press or knock them out, ... The 120 volt primary resistance is about 0.3 ohm; ... > ohm speakers - too low; also need to isolate the secondary from the ...
    (rec.audio.tubes)
  • Re: OT: Transformer from a microwave oven
    ... Engineer wrote: ... The 120 volt primary resistance is about 0.3 ohm; ... > ohm speakers - too low; also need to isolate the secondary from the ... > power an electric fence. ...
    (rec.audio.tubes)