Відео

How about my generator

Look at my video, there is a circuit

Please do so abd add in amazon affiliates links

I am using a normal N channel Mosfet here. I don't remember the part number, but It's rated for much much higher voltage and current than required (I think rated for 800V, 120 A continuous, pulsed to 1000 A). But I did add small amount of resistance to guarantee some sort of current limit (about 1 ohm). It's also avalanche rated. I did not have any issues with it burning up, but I definitely had some issues with noise and clean switching. I added a low impedance mosfet driver on the gate, kept all the wires short, etc. etc. all the standard stuff. I think if you don't limit the current you will always burn up your switches. The resistance and inductance in those short wires is super low. The "proper" way to do this is to add inductance in series with the switch, and control the duty cycle like you would in a buck converter. This requires extremely fast electronics, though. And a lot of math and careful design to prevent oscillation.

Thanks so much. This is a 1999 Martin DM. I still need to learn a lot about recording audio, but I think it's a good start. I appreciate your comment.

Sorry for never replying to this. If I remember correctly, I played with different frequencies and duty cycles, and determined that 30-40 kHz with 5-15 microsecond pulses worked the best. The duty cycle was chosen/discovered such that the bulk capacitors were allowed to recharge mostly between arcing. This gave me the most consistent results. If the electrode voltage was below about 60 volts at the beginning of a spark, it would not reliably initiate an arc. IIRC I ran the bulk capacitor around 90 V max, and during arcing it would measure 75-80 V with a DMM.

@@gizmoguyar "The duty cycle was chosen such that the capacitor was allowed to recharge between arcing" Was the RC-Circuit-frequency a straight multiple or straight fraction of the frequency of the mosfet-switching, or was it chosen so that both have nearly the same frequency? Thanks !!!

@@klausbrinck2137 It was neither. I empirically measured the RC time constant, and I used a MOSFET frequency of about 4-5 times that. This way I could be confident that at the beginning of each pulse, the capacitor was roughly at the same level of charge, independent of the size or length of the previous pulse.

@@gizmoguyar This answer was very satisfactory, finally I know about the relationhip of the 2 oscillating systems !!! Thanks a lot. The ratio may be different for my efforts, but, at least, now I know what I should pay attention at. I know nearly nothing about electronics, all I do, is to logically evaluate all statements expressed here, bring them in relation, and find the truth. My biggest fear was, that the "ON"-part of the mosfet-duty-cycle is gonna precisely overlap with the least-charged-capacitor-state of the RC-oscillation-cycle, for example. But your answer tells me, that I shouldn´t fear that much, generally... Thanks again !!! I endlessly envy your results, greatly done !!!

Yes, I'm sorry about that. I recorded this with my phone, and it was doing some strange noise suppression stuff (there were other noisy machines running in the room). ...one more thing I need to learn.

@@gizmoguyar 😁No prob, we all must live and learn, otherwise we may not live long enough to learn LOL

ua-cam.com/video/8gjdXbLPsxE/v-deo.html

Looks like a great machine. I agree with the other guy, your linear motion is very jerky and large. I would add filtering and tune your PID so that you get smooth slow downward motion. Your cut speed will increase, and your surface finish and tolerances will improve.

The sound was music to my ears, and the light from the sparks was barely perceptible, exactly as should be !!! I mean, he surely is my hero, but I´d love to know more about the circuitry and the PWM-generator , as well as the cap-voltage-sensing/code... I cannot program an arduino as a PWM-generator, but there´s very cheap ones to buy, but I cannot judge whether such one is gonna pair well with the Mosfet I will use.

I took a look at your video, and I'm super impressed. You have done some amazing work. The Stirling engine looks really great as well. Unfortunately I don't have any schematics or other documentation that I can give. But I can explain the additional circuit that I added. It is simply a very high speed mosfet and high current mosfet driver in between the capacitor bank and workpiece. The mosfet circuit is optically isolated for safety. I also needed a snubber to handle the high current flyback from any stray inductance. The arduino outputs pulses of varying length and frequency to the mosfet circuit. It sounds like you already know more than I do about tool wear and different materials, but adding this circuit may help. I used very short pulses, about 10 microseconds. And I used a frequency of about 5-10 kHz. Although I didn't investigate reducing tool wear heavily, I can say that I did get some cuts that were quite good. About a 5 to 1 wear ratio was the best I got. Regarding the stability of small tool areas. This is simply a matter of tuning the feedback loop. I suggest using a much smaller discharge capacitor (around 0.5 to 1 uF). And adding additional low pass filtering on the feedback signal. I did all of the PID tuning digitally on the microcontroller, which was much easier than tuning an analog circuit. Best of luck!

@@gizmoguyar would be possible to prepare some schematics for us non-experts in electronics together with arduino code and BoM? Do you have some patreon to send you money for that?

@@jozefdzugan1828 I'm sorry, no. I work full time as an engineer, so I don't have time to prepare well documented schematics and code. I also generally don't like to do that, because I want people to learn the underlying principles rather than copying a schematic for something that is extremely dangerous.

@@gizmoguyar OK .. I understand your point.. anyway thanks for sharing your knowledge in video.. But what about sharing at least arduino code via pastebin? It is not very time consuming I guess and for me it would be very useful

@@jozefdzugan1828 That's fair. I'm not familiar with pastebin, but I will see if I can dig up the code for you.

Nope, sorry. I'm not a freelance machinist.

It's made from polyethylene terephthalate with glycol. It can withstand temperatures much higher than boiling.

@@gizmoguyar lol thats a mouthful. Thanks for the info.

I never said it was, genius.