When I exchanged the spindle motor of the CNC from 230W to 400W and the power supply from the unknown underpowered linear crap to a 600W switching mode supply, the later one just blow because of the missing protection diode (my fault)
When I started to repair the above supply, I made the second mistake. I forgot that all mains powered oscilloscope is ground referenced. Second blow, and the repairable supply completely destroyed.
So Is started the CNC motor driver project and on the side I figured out that I definitely need in isolation transformer to avoid such kind of accidents.
I ordered, bought several parts for the transformer - a toroid isolation transformer, an enclosure, switches, connectors, and a nice multifunction panel meter, what able to measure volts, amps, watts, voltampers, and power factor.
All of the parts was lying around in my workshop, as I didn't want to cut, drill the necessary holes to the front and back panel of the enclosure, by hand. I waited to finish the CNC, to do this job.
A few weeks ago I was thinking of testing some power supplies for the home automation project. As I built an electronic load for this, the isolation transformer also appeared as a required tool.
Today I'm in a better situation. May CNC still doesn't work, but the 3D printer does. So what if I just replace the aluminum front and back with plastic, as I did in the electronic load project.
I did it.
Here is the result: