Jesse Log

Wen Aug 15, 2018

• Began compiling transformer disassembly/rewinding videos.

• Some notes were generated in a conversation with Miles and Marcin:

"I think we should try both and record the results! I've got some diodes in now so I can rectify the wall power then break open a few PC power supplies for hopefully ballpark capacitor values. My adventures in rewinding transformers have led me to believe that we should likely wind our own rather than subject people to the power tool experience thresholds needed to disassemble a core gently enough to preserve primary windings. Finally yeah, I think if we can find a way around a transformer we should, I just respect the things as a common component worth getting to know.

Winding our own transformers would give us the ability to wind multi tap transformers for a large range of voltages which could be rectified more efficiently if the power loss from the buck boost/ arduino controlled power transistors is too great.

So I wonder, if we rectify the 120V AC then smooth it out with a nice big capacitor, I think then we could just use something simple and easy like a voltage divider to give the arduino the power it needs to start regulating the now smooth DC into duty cycles through power... I could be wrong on that and the buck boost is the stable way to go, but at this point we will get to try some things and see what works unless anyone has some more definite direction for this after the rectification and capacitor smoothing parts.

Finally, have any of you had any luck modelling existing components not in the qucs library into the program? I can just try and build a rectified smoothed transformer-less power supply and measure it and see what happens in real life but simulations are more efficient. "

Tue Aug 14, 2018

Finally got a solid hit looking for used kijiji microwaves. Arranged a meeting nearby and will transport it home for the great price of $15. Another one lined up for Friday. Once I've got the used microwave I'll get to work on making the safe microwave transformer salvage guide.

• Went to get the microwave! Brand is Emerson, specs on back claim power of 1.4KW single phase grounded with max power output at 1000W max.
• Added transformer steel to Electronics List
• Attended my first video meeting!
• Disassembled microwave and recorded process of disassembly and salvage of transformer. Safely disassembled core and found ways to remove the primary coil with minimal damage. It was really difficult work though, it really might be easier to make our own transformers once we could find an affordable source of transformer steel.
• My next task will be compiling the video I took from various camera sources into a how to guide with kdenlive.

Rewound transformer and re attached primary. Temporarily reassembled core to test for voltage (multi-meter read 0.075V, might really be 75V cant be sure will get new meter) and amperage (1.4A), touched the wire together on my re-wound secondary coil for an intense spark! It would be interesting to see what a buck boost converter could do with the stepped down power.

Maybe we could consider using multiple points in our power supply which were rectified then put into a buck boost circuit (one at wall voltage, one at stepped down voltage, perhaps one at a higher voltage, so as not to strain their range/loss?). Lots of video to compile now though!

Mon Aug 13, 2018

Read the safety considerations in power supply design pdf file.

Sat Aug 11, 2018

Practiced using Quite universal circuit simulator.

Fri Aug 10, 2018

Created Microwave Transformer page on wiki. Linked newly created page to the possible parts section of the Research Development page for the Universal Power Supply.

Some of the parts salvaged from the microwaves might have use in the Universal Power Supply project. There are some high voltage relays, micro switches, and some nice fans that run off 120v AC. This is just to name some of the parts. While safety should be considered if you are going to harvest the microwave capacitor as well as the magnetron- as long as you discharge the capacitor and bag up the magnetrons you salvage you should be fairly safe as long as you follow safe electronics practices. The magnatrons contain a dust thats bad for lungs so they should be sealed away in airtight bags.

Also learned about QUCS (Quite Universal Circuit Simulator). Downloaded and installed a copy and found a Tutorial..

Thu Aug 9, 2018

Studied:

       * Current tasks
       * Crash course on Power Electronics
       * Electricity
       * Electronics List
       * UPS Initial Design

Contacted two more Kijiji users about cheap used microwaves in range.

Wed Aug 8, 2018

Sourced a few cheap ($10) microwaves on kijiji in the area and contacted sellers.

Tue Aug 7, 2018

Finished modelling then uploaded free-cad model of microwave oven transformer core. Ordered some KBPC5010 high current bridge rectifiers.

• https://wiki.opensourceecology.org/wiki/File:Transformercore.fcstd
• https://pdf1.alldatasheet.com/datasheet-pdf/view/34010/WTE/KBPC5010.html

On a side note, I successfully salvaged three microwave fans and mounted them to a wooden frame, then connected them to a wall main in parallel. They all run on 120V AC and are a convenient salvage for cooling future projects (and work-spaces!)

Mon Aug 6, 2018

Recorded dimensions for one of the disassembled microwave oven transformer cores. Also recorded transformer core slice thickness at .025" or .635mm and began modelling the transformer in free-cad. In the future I should make a short guide on salvaging parts from microwave ovens and what can be found as well as the best ways to get at the goods. Should also look into places from which to order the core slices to replicate this design or one similar to it in the future. The slices, if made from scratch, should be painted with an insulator to reduce magnetic eddy currents which contribute to heat buildup. Cold roll steel seems to be the way to go. This article states a silicon content might help as well if we ever end up pouring our own steel.

Transformer Steel

Sat Aug 4, 2018

Disassembled one microwave oven transformer. Learned how to liberate the primary and secondary coils- but need to be more gentle next time, I damaged the enamel on the winding for the primary so I'll have to try again with another core. Got an unmodified core hooked up to power and producing arcs in order to have a hands on understanding of a high power transformer in operation. We should mount it on a massive heat sink if we end up using this component. I plan to model a microwave core in free-cad soon for reference, will have to engineer a hinged transformer core or maybe just screw holes for easy core winding access if replacement winding need ever be addressed. Ordered some different gauges of enameled copper magnet wire.

• Microwave oven transformer salvaged from the alley

• Disassembled microwave oven transformer.

Fri Aug 3, 2018

Studied the Universal Power Supply. Noticed the possible use for microwave oven transformers, in all of their high power glory. Decided I'm going to try to rewind a microwave oven transformer core secondary winding to provide 30v at around 2 amps to the buck converter circuit, which I ordered ten of off amazon for something awesome like $2.40 a piece.

Thu Aug 2, 2018

Learned the basics behind how to dimension drawings in free-cad. Took half an hour to download and explore dimension drawing workbench. Still need to learn how to change the Title and info in the bottom right table. This is what I have so far. Practice dimensions

Sent an email to info@opensourceecology.org to notify them of completed steps.

Wed Aug 1, 2018

Learned how to use Vokoscreen to record myself through the webcam on my laptop which was running the OSE live-USB. Recorded the video interview questions and uploaded them to youtube.

http://img.youtube.com/vi/9y8gRox_JXI/3.jpg

This took about an hour and a half to get to work as I had to calibrate it to proper settings to get it to record the sound in sync with the video.

In the end I used Window style recording and clicked on the webcam window to record just my image while reading the questions. I left the frame rate at 25, changed the videocodec to mpeg4, avi and the audio format I left at libmp3lame.

Sent off an email to ops at ops@opensourceecology.org to let them know I've completed the steps in the list.

• Update: Linked to corner_cube_test_video and learned how to upload my freecad file to the wiki.

Download corner_cube.fcstd

http://img.youtube.com/vi/zroXi9xBAUY/3.jpg Link to Corner cube test video

Time frames:

1. Installing Linux: 20 minutes
2. Learning Free-cad: 3 hours of trying to get faster and more comfortable.
3. Documenting my work: 2 hours learning to organise on the wiki.

The hardest part was learning to use Free-cad. Its a tricky program with tons of tools and features.

Ill give myself a score of 95%. I'm missing some formatting techniques to make everything here appear clean and concise.

Tue Jul 31, 2018

Created live-usb and installed OSE Ubuntu OS to my desktop computer. Used the live CD on my laptop to record the desktop video due to microphone requirements. I'm having a hard time getting the sound to work with clarity on my laptop microphone for the video interview so ill give it a try tomorrow or start looking for old external microphones around the city. Recorded developer test video. Learned to edit video down to appropriate size and uploaded to youtube. OSE_DEV_TEST

Freecad is a lot to learn but now that I can use it a bit more reliably, its not crashing anymore and I am learning ways to speed up my workflow. One of the most useful tricks was the (ctrl) selection of files to mass rotate a bunch of copies. This saved a lot of time and will be a useful technique in the future. Hot-keys and always save!