Re: Audio amplifier as AC power generator ?

Phil Allison wrote:
"sycochkn"

"Robert Lacoste"

I was looking for a low cost AC line simulator, something able to generator from 90V rms to 250V rms, from 50 to 60Hz, able to generate glitches, etc, and apparently these test equipments are still quite expensive even on eBay. As I need only a small amount of power (say less than 100W) I was wondering if someone has already tested the following setup : A lab sine generator (or ARB if needed) set to 50/60Hz, a low cost audio amplifier (units up to 500W are available for 50$ or so on ebay, and should be happy with a 50Hz signal), and a 48V/220V transformer driven on its secondary side. Of course the impedance seen by the amplifier will never be 4 ohm or 8 ohm, and will vary depending on the load on the high voltage side, but it should work, isn't it ?


Sounds good to me



** ROTFL !!

If ignorance is bliss, this dude is in heaven.



....... Phil



Just use a transformer whos secondary voltage rating is about twice as high as you need. Then the peak flux will be about half what it was designed to run at, so even in the worst case it will never saturate further than it does during normal operation (that last bit is included because some 50/60Hz transformers saturate like hell twice per cycle. Microwave oven transformers are a good example of that, as are many autotransformers)

try it, its easy.

Or do what I did with my 3kVA light dimmer, and have transformers built that run at a peak flux density of 800mT.

And if the OP wants to produce even lower frequencies, all he needs to do is keep the ratio of volts/hertz constant, and the flux stays constant - this is how all non-vector AC motor controllers work, and is usually called V/Hz or scalar control. At very low frequencies you need to "boost" the voltage a little bit to offset IR drops.

Cheers
Terry
.

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