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Re: [TCML] "Wall Wart" Transformers
Hey Leonidas...
your theory seems plausable but in reality it wont work. There are 
several things working against this senario. Reversing the inputs to a 
120 to 12 volt trannie will overheat the windings on the reverse side 
due to the thin wire used to make the trannie. Basically, the reverse 
winding idea will act as a short circuit and melt the wires.
Second thing working against you....  the core of the trannie is very 
small compared to an NST,  the required magnetic flux needs a pathway 
large enuf to move thru to maintain a "stable" flow, the core size also 
determines how much flow can be transfered to the windings to supply the 
needed power on the transformed voltage side.
3rd thing not in the favor of the theory...  the number of windings of 
the primary side compared to the secondary side ( nst) need to be 
basically 1 to 100... unfortunately, wall transformers are 10 to 1   
thus 120 in 12 out    nsts are 120 in 12000 out  reversing a wall 
transfomer will " give" 1200V out if it were possible... 
also, the number of windings on the 120 volt side are usually 200 or so 
turns due to wire resistance required to keep the 120 volts from seeing 
the wire as a direct short or low resistant load...  the lower the 
resistance, the more current can flow thru the length of wire thus 
causing quicker heating of the wire and then smoke....
I know this is a crude way of stating this application but it seems to 
work when a quick explination is required...
Hope it helps...
Scot D
Leonidas Tolias wrote:
I had a few of those big black "Wall Wart" transformers lying 
around.   i pulled some apart and noticed that they have some nice 
looking  transformers inside them.  The transformers have EE cores, 
with the  cores made of interlocking metal Es.  the primary and 
secondary are  wound side by side, not primary on top of secondary, or 
vice versa.   Some have center taps on the original secondaries (which 
we would use  as primaries).  By running them in the reverse of their 
normal  configuration, and possibly removing several winding from the  
primaries (seems like an easy way to make the turn ratio larger),  
would it be possible to use them in tesla coils? this would make  
transformers basically free, and i would hate to keep buying NSTs and  
OBITs if there were such an easy cheap alternative. 
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