120 vac to DC

Thread Starter

abstruse1

Joined Jan 18, 2021
6
Greetings. I have a 20 amp rated 120 vac variac autotransformer and would like to change its output voltage to DC, still with around 20 amp capacity and voltage to around 120vac. I'd rather not have to make anything (unless its very simple). I'd rather buy something readybuilt.

The output voltage will be used to power electromagnets (microwave oven power transformers with secondary windings removed).

My area of knowledge is machine work, but I am comfortable with electronics as long as I know exactly what to do.

Thanx!
 

Sensacell

Joined Jun 19, 2012
2,821
I modified my own variac with a 20 A 600 PIV bridge rectifier, along with a switch so I can select either AC or DC output.

One needs to be very careful NOT to accidentally supply DC to devices using transformers or induction motors.
 

crutschow

Joined Mar 14, 2008
27,188
Also, If you are not aware, the output of a Variac is not isolated from the mains as are most line transformers, so there is a danger of electrical shock to any ground from either output connection.
 

Thread Starter

abstruse1

Joined Jan 18, 2021
6
Also, If you are not aware, the output of a Variac is not isolated from the mains as are most line transformers, so there is a danger of electrical shock to any ground from either output connection.
Thanx, guys. I’ll see what I can find.
Sounds like it might be a good idea to isolate the variac from the mains. I suppose an isolation transformer would do this?
 
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