Gizmosmith

Plasma cutter rectifier heatsinks

This evening, I added heat sinks to a couple of rectifiers that I’m planning to use in the power supply of a DIY plasma cutter. The rectifiers will each be handling half of the power load of the device, so I have beefy 35A/600V rectifiers. Each rectifier has a square metal case with a hole in the middle, so I drilled and tapped a hole in a the centers of a pair of CPU heat sinks and bolted the rectifiers to the heat sinks. This picture may help to make the assembly clear.

I had high hopes for the original fans that were on those heat sinks, but the lubricant that was in them had turned to gum, and so they didn’t spin. The new fans are from laptops, and run on 5V.

I’m planning to get the 5V from the low voltage filament windings of the microwave oven transformers that I’m using for the isolation transformer of the power supply. There are two sets of two transformers, wired “back-to-back” to act as isolation transformers. I’m going to post a complete schematic as soon as the power supply section of the cutter is fully assembled.