Articles

HACKED!: Microwave Transformer becomes a High Current Transformer


a while back I built this electric motorized longboard that still works to this day but over time I noticed the biggest mechanical weak spot of the system which is this one pole connection to the truck so the question is how can I improve the stability of this joint and the answer is all over the Internet’s what I need is a weld and luckily I recently found this old microwave whose high voltage transformer can more or less be easily converted into a high current transformer that could function as a stick welder so in this video let’s do this transformation have some fun with high current tests and see what I’m capable of creating a weld in the end let’s get started first off I removed all the screws that held the top cover of the microwave into place and took it off afterwards on the right side you can already see all the interesting electronics components that we can salvage I started with the main control PCB year which contains a useful relay and a cup of high-power resistors then followed the main power cord the thermal fuse a small light bulb a cooling fan the magnetron which contains two rather big and useful magnets a high voltage capacitor with a high voltage diodes a timer relay limit switches an AC motor and finally the long-anticipated transformer in addition to the remove screws I would say that a couple of those components will be helpful in the future but for now let’s focus on the transformer it’s top label wants us about high voltage and from the side we can see the two main coils or the system the lower one is the primary coil which directly hooks up to mains voltage with its two terminals the upper one is the secondary coil which creates a high voltage between its output pin and the iron core of the transformer as the first test I use my auto transformer to power the primary coil whuppin AC RMS edge of around two bolts this resulted in a voltage of 17.2 volts AC on the output of the secondary coil which means the transformer has a theoretical transformation ratio of 8.6 thus our transformer usually outputs around 2 kilo volts which is definitely not our goal to English projects we want high current instead so we need to replace the secondary coil for that I personally removed the protective paper plastic layer and then slowly and carefully cut through the middle of the coil on both sides and remove the excess cup of strings along the way after clear separation of the coil sites was established I use my rotary tool with a cutting wheel to trim off all the excess copper in order to create a flat surface then I use my drill to create holes inside the coil and remove the remaining copper by pulling it out all in all this process was rather tedious and time-consuming but in the end it worked out just fine for the last step I move the additional low-voltage coil and use my screwdriver with a hammer to knock out the two shanks right above the primary coil then I grab two meters of 70 square millimeter thick wire and phoned the new secondary coil by winding the conductor two times around the iron core afterwards the high current transformer was completes and produces around 1.7 volts AC on the outputs which is even safe to touch so it was time to head out and perform some tests with two aluminum plates whose material is similar to those of the trucks and motor mounts I connected one side of the secondary coil directly to the sheets while the other side was hooked up to Universal pencil electrodes but all I got in the ends were only a couple of sparks and the current flow of around 60 amps and even by using a special aluminum electrodes no electric arcs were seen the reason is the low output voltage which might be useful if you want to heat up a coin or a nail or a piece of metal or even a brush but it is not so for arc welding that is why I had a plan B R which is a transformer from a different microwave again I removed the secondary coil of it’s in pretty much the same manner as before except that I used my rotary tool with a cutting wheel right from the start after I successfully knocked out the shunts from this transformer as well I use 16 square millimeter wire to form a new secondary coil with a total of eight windings four inner ones and four outer ones which resulted in an output voltage of around 7.5 volts ac so once again I hooked up one side directly to the material and the other side to the pencil electrodes but the results were still unsatisfactory year with the universal electrodes the aluminum electrode on the other hand showed a bit of potential but still no successful welds maybe a bit more voltage another kind of pencil electrodes and someone who actually knows how to welds could make this work but I hope you still enjoyed watching this failed attempt and maybe I will improve this project in the future as always don’t forget to Like share and subscribe that would be awesome consider supporting me through patreon to keep such videos coming stay creative and I will see you next time

Be the First to comment.

Leave a Comment

Your email address will not be published. Required fields are marked *