Plasma Cutter

[Micke S]

I need to cut thick steel from time to time and ordered a cheap Plasma Cutter directly from China. It is a risk of course but even if it fails there are so little money to loose. This one costed less than 300 dollars including delivery to the door by FedEx.

I started to check the unit inside. It is important that power transistors and diodes that are paralleled are well tightened to the heat sink. Otherwise some will get higher current and fail. The reason is the characteristics of semiconductors are temperature dependent, which will effect the current in them and how the total current is evenly divided between different components.

Most of the components were possible to tighten a 1/4 turn for a good fit. The same with high current joints, which should be well fastened to avoid burn damages and current reduction. I also looked over solder joints to check that they are professionally done and that all connectors are fitted. In case cables are routed so they can scuff against sharp edges they should be securely fixed by tie wraps.

The cutter is a 3-phase machine. The mains wire only included three wires, one per phase. But a ground cable was missing so I replaced it. I finally vacuum cleaned the interior and boards before blowing everything with air pressure. I hope it will be trusty and last after these preventive actions.

https://www.youtube.com/watch?v=8l2olBlt5ZY&feature=youtu.be

 

[xalky]

You can't beat the price, that's for sure. That' s less than a good torch setup without the tanks. )

 

[Micke S]

Yes it seems to be a good find. I'm not going to speak with the machine so it doesn't matter much that we don't share the same language.

But the most satisfactory finds are when you can buy old equipment for a good price from times when companies were proud in making real quality items.

 

[davidh]

im not positive about this but it seems to me, on my plaza, if i cut f a s t it eliminates most of the slag. . .

 

[Rbeckett]

You reduce the slag and the need to go back and clean up by controlling the speed which the torch moves. You want to move as fast as possible while still getting full cut through the metal. If you slow down the slag will start to build up on both the top and bottom edges and is a PITA to grind off for a finished edge that will be used for some other purpose.

Bob