connecting right?

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alright i have aquired an ei core type step down transformer that i am using in reverse.....it's primary is 230volts and its secondary is 12 volts....every tiem i try to connect it i get huge sparks at the terminals.....so i just hooked it up and flipped the switch on my pwm......it gave a good 2 second go then hissed and smoked.....i think i blew my mosfet....i have my pwm to transformer hooked up as the following picture below.....are my connections wrong or is this type of transformer no the right type....it is meant for ac current but i am pulsing the dc soo.....it's also a single phase transformer....

(http://i2.photobucket.com/albums/y2/kinesisfilms/pwmshortcircuit.jpg)

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Hi,

I had the same thing some weeks ago. You must start at a very low frequency with pulsing.
like 10hz.

My toriod trafo didnt like frequencys higher then 1 khz at the end......
Above that, you will short out everything!

Hopes this helps

Br
Steve

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hmm i see.....when i use it as a step down transformer it seems to work perfectly...but only in reverse does it bite back...thank you though....i am just going to repair it and build another one.

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yeh, you better have some FETS on stock...you will need them!

br
Steve
Master FET killer