Here's a picture of the front, sitting on the work bench. The left two outlets get power through the isolation transformer. Those are the ones that matter. Meanwhile, the right two outlets are powered directly from the wall outlet - which makes them basically an extension cord.
I removed the cover to see what's inside. A hefty 1:1 transformer, meaning that it doesn't step the output voltage up or down. This thing just uncouples the power electrically from the outlet.
When I first opened it, all of the ground leads were tied together by a thin silver wire, where the red MS paint line is now located. I snipped that out so that whatever is plugged into the isolated outlets won't be tied to ground.
Wires gone!
I've tested this and it works perfectly. I'm quite happy with it.
The other thing that arrived today (and I didn't have time to get pictures of it), was a variable autotransformer - frequently called by the trademarked name, "Variac".
A Variac allows you to adjust household input voltage quite smoothly from zero volts to greater than 120 volts - typically only up to 130 volts. This is really handy when you have old electrical stuff and you don't want to just switch it on and put 100% juice to it all at once.
Below is what a Variac looks like:
How does it work? There is a primary transformer winding that is connected to the power cord. It is wound in a cylindrical shape, with the secondary transformer wound outside of it. The secondary coils can be added or subtracted from the electrical circuit with a wiper arm connected through a carbon brush.
Physically the inside of a Variac looks like this:
The carbon brush is inside the holder to the right. As the brush rotates along the secondary windings, it adds or subtracts windings from the circuit, increasing or decreasing the output voltage.
Electrically it looks like this:
Pretty simple. Not cheap. Or light. There is a lot of iron and copper in a transformer.
1 comment:
Thanks for sharing this valuable information.
variac transformer
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