Strange transformer

[db!]

I was recently given an oil filled hermetically sealed transformer, probably off some military equipment since "MIL-T-2/A" is written on it.

The primary is rated for 115VAC 3A @ 320-1760CPS which is rather unusual. Would it be okay to run off 115VAC @ 60Hz or will I blow something up?

thanks

[Don Hills]

You will blow it up. (It will overheat.)
It was designed for use in aircraft or similar, they use higher frequency AC, usually 400 Hz, this enables them to use smaller (and thus lighter) alternators and transformers. (The higher the frequency, the less iron you need in the core.)

[db!]

So, I guess it's pretty much useless practical purposes?

[indianajo]

400 up hz transformers are useful for switcher supplies, as cheap as FET's are these days. Look at threads on the amp power supply section, or cut up a dead PC switcher supply and learn from what is in there. Of course for audio, a 400 hz switcher might howl pretty bad into the speaker. The lounge thread "why does NASA sound so bad" has something to say about that. audiopower.it makes audio intended switchers at 87 khz, high enough not to hurt your ears.

[db!]

Thanks for the suggestion, I was just toying with that idea of building a SMPS that puts out 400Hz! However, this is way beyond my electronics experience; unless there is design that I could easily modify I don't think I'll attempt it.

I am also considering using a sine wave generator and a simple transistor "amplifier" to produce 110vac @ 400hz. Any thoughts on this?

[indianajo]

There are easier ways to do switchers, although I have thought of doing this too with a two transistor phase shift oscillator I built. (I don't have a suitable transformer, so stop there). There is something called the "flyback" circuit that uses a $.15 555 timer IC that somebody recommended for starters on the power supply thread. There are also canned IC's for doing switchers. The Peavey CS800s has a combined oscillator-how are we doing? IC (measures output voltage) ML4825 microlinear corp. They then buffer is with a SG3644 power buffer to drive the switching FET's. See the CS800S schematic on eserviceinfo.com, page 9. I think the PC power supplies I've examined use various optoisolators to relay the "how are we doing' signal to the oscillator IC from the various output voltages.

[db!]

Would it be possible to crank up the frequency on a standard 12v - 110v inverter? I have looked into various inverter circuits and unfortunately, they are either too complicated and/or they can't deliver the required power.

This transformer is getting to be more trouble than it's worth I might just take it to the metal scrappers if I don't find a practical way to utilize it...