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# Transformer question

Junior Member
Join Date: Aug 2010
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 08-12-2010, 01:10 PM
I was curious, for a transformer why is it that increasing the voltage reduces the amount of current that is transmitted?

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Last edited by brownr72; 10-13-2010 at 12:11 AM.. Reason: .

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 08-12-2010, 01:52 PM
Because the power remains constant (less any loss in the transformer)

power = voltage * current

(It's a bit more complex than that, but that is enough to show you why)

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Location: Mojave Desert, CA, USA
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 08-25-2010, 05:24 AM
Good answer – even though the question is a bit misleading. To put it in concrete physical terms, any particular transformer design is limited in power output by its ability to effectively shed heat. Continuously overload a transformer of any size, and it will ultimately burn up through failure of its insulation system. Within the limits of any fixed size of transformer, there is a finite, fixed limit of allowable power loss. Increasing output voltage means increasing the number of secondary turns. With a given size core, to physically fit more turns on the secondary, the size of the secondary wire must be reduced. The additional number of turns also increases the total resistive length of the secondary winding. More turns / smaller wire = higher secondary resistance = lower output current at the fixed limit of allowable secondary power loss.

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 09-01-2010, 01:25 PM
While I doubt that the o/p (a spammer) will comprehend (or care) about neither the question nor the answer, someone else might benefit. Thanks.

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 09-02-2010, 04:35 AM
Thanks for "scraping" up the spam, Resqueline - I never spotted it - and though I have to admit I eat the greasy canned variety from time to time, I never appreciate having the other kind jammed into my face!

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 09-02-2010, 09:05 AM
Hehe, yes, even if canned & greasy some kinds are certainly more "digestible" than others. Then there are the grey areas too.
They devise ever changing ways so one has to be really vigilant, and some can be hard to distinguish from simply "unenlightened" individuals.
The latest "fad" seems to be editing in a link a couple of days after posting the first seemingly lame but harmless question, hoping it will go by unnoticed by the mods.

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 09-02-2010, 12:53 PM
Quote:
 Originally Posted by Resqueline hoping it will go by unnoticed by the mods.
I suggest that it probably goes unnoticed by most users too.

I suspect that the links are for google, not real people. I've noticed that google hits this web site really fast, and hits get very highly placed. That makes it a target for the less scrupulous SEO operators.

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