Can I use step down transformer as step up ?

[Frosty_47]

Hello,

I would like to use a 12V step-down transformer as a step up to 1200V. That is, I want to apply 120VAC into secondary and take my output from primairy. This should give me 1200VAC at the output. The transformer is ratted for 10A on secondary. Which means that it's primairy can handle up to 1A. My load on primairy will be 0.5A. This means that the secondary thats connected to 120VAC will have a load of 5A. Is it acceptable to use a step-down transformer in this configuration ?

Thanks

 

[Claude Abraham]

No. If the xfmr steps 120V rms down to 12V rms, then in reverse you must limit the input on the low side winding to just 12V rms. The output will be 120V rms. The current ratings for each winding still apply.

Do not even think about energizing the low side with 120V. The core will saturate, the magnetizing current will be abnormally high, the voltage on the high side will reach dangerous levels, and the xfmr will overheat, as well as insulation possibly breaking down.

What you describe involves lethal shock hazards. If you are not familiar with xfmrs or electric power in general, I'd advise you not to tinker with voltages of this magnitude. Please heed my advice. Best regards.

 

[Frosty_47]

No. If the xfmr steps 120V rms down to 12V rms, then in reverse you must limit the input on the low side winding to just 12V rms. The output will be 120V rms. The current ratings for each winding still apply.

Do not even think about energizing the low side with 120V. The core will saturate, the magnetizing current will be abnormally high, the voltage on the high side will reach dangerous levels, and the xfmr will overheat, as well as insulation possibly breaking down.

What you describe involves lethal shock hazards. If you are not familiar with xfmrs or electric power in general, I'd advise you not to tinker with voltages of this magnitude. Please heed my advice. Best regards.

Thanks for your advice! I will not proceed in such a case than.

However, I was wondering if I could wire a microwave oven transformer to a 70VAC step down transformer. This should give me around 1166VAC at the output. Since microwave oven transformers are ratted for 2000VAC output, that gives it a 16.667 ratio between primairy and secondary. 16.667 * 70VAC = 1166VAC. Is this acceptable configuration ?

 

[Hero999]

Another option would be to increase the frequency by a factor of 10 but good luck building a 120V 60Hz to 600Hz converter.