Blowing a 35amp 200v (7Kw) rectifier takes some doing as they will take alot of abuse via their momentary rating.
I suspect that it may be due to the lack of isolation you have, you mention 'Ground', Ground and Common are terms that are often miss-used.
If in fact you have either deliberately or accidentally a connection of the Common to Earth Ground you will blow the rectifier, using a non-isolated source like a Variac.
I always ground my power supply commons, but I ensure a controlled situation by starting out with the proper isolation.
Al.
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CNC, Mechatronics Integration and Machine Design.
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E. |