Tranformer input options?

[Bloy2004]

Please see this item...http://cgi.ebay.com/ws/eBayISAPI.dll...MakeTrack=true

Why does it state the inputs as such "ONLY"?

Can't any amount of input voltage be applied and the resulting output be relative to the input? And how is the amperage affected by lowering the input to 115 or 120 VAC?

[trubleshtr]

I believe the higher the voltage the lower the amperage (ohms Law) if resistance stays the same.

I see Al is here, he can explain this best I bet

[OCNC]

Originally Posted by Bloy2004 Please see this item...http://cgi.ebay.com/ws/eBayISAPI.dll...MakeTrack=true Why does it state the inputs as such "ONLY"? Can't any amount of input voltage be applied and the resulting output be relative to the input? And how is the amperage affected by lowering the input to 115 or 120 VAC?

I think the seller is implying that there is no 120v tap. Otherwise as long as the primary has enough inductance not to draw too much current you should be able to use 120v on the 240v input to get half the output rating. You won't be operating it at peak efficiency but that probably doesn't matter for your intended application. This is my amateur opinion so you should wait until one of the pro's comments before you buy.

Chris

[Al_The_Man]

Generally you can get away with it, but the KVA rating and the voltage drops proportionatley to the difference in voltage you apply.
The efficiency drops slightly also, although you may not notice it unless you run at max. current.
A transformer is designed to provide a certain magnetic field to overcome the iron losses etc and this depends on the turns/volt ratio and the voltage applied. You effectively doubling the turns/volt ratio by halving the voltage.
Al.

[Bloy2004]

Thanks All!
I ask because I am inputting 115VAC into a toroid designed for 230Vac (Remember Al? the one I took way too much secondary off to bring down the ouput voltage....I was exasperated after drilling,chiseling, picking out the big epoxy core and didn't check often at intervals for output voltage).
Was wondering if these types of transformers reacted about the same.
...Always looking for more options for supplys(at a good buy)...having fun experimenting with electricity...

[Al_The_Man]

Originally Posted by Bloy2004 Thanks All! Was wondering if these types of transformers reacted about the same. ...Always looking for more options for supplys(at a good buy)...having fun experimenting with electricity...

The square lamination type works the same way except the turns ratio is usually larger, 5turns/volt as opposed to Toroid about 2t/volt.
In my early days in the Electronic/electrical field, toriods were rare as the technology for winding them efficiently had not been developed, as this was during my relative poverty era. I had to resort to dismantling Square type transfomers for customize rewinding, if you really want a challenge try these types some time.
Al.

[Bloy2004]

LOL Ya! That toroid was a handfull in itself! The sweat was dripping as I managed to rewind it without tangling the 45 feet of replacement AWG 10 wire.