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Registered Member #2906
Joined: Sun Jun 06 2010, 02:20AM
Location: Dresden, Germany
Posts: 727
If I understand you well, your idea is to put a wire wound resistor in series with the anti parrallel diode, and wind this resistor around the main coil, but in a reverse way ? Is that it
Yeah.. something like that. I would follow these steps: 1) calculate the aproximate length of the used wire for the main coil 2) calculte the resistance needed 3) with a wire as long as the "main wire" what diameter would you need to achieve that resistance - this is much thinner than the main wire... so it should fit in the emptiy spacec of the coil (hopefully) 4) wind the 2 wires (thick main wire an thin resistive wire) in parallel to minimite stray inductrance 5) put a diode into it and... lets go...
however i can not guaranteee that this would work. Single hotspots inside the thin wire could blow everything. One need to caluclate the heating verry carfully and with a large margin for error.
"Left by themselves, my IGBTs turn off in 8us. Maths: E=99u*300/8u=3.7kV possible if you don't slow it!" - Um, I thought the bunch of diodes are stacked antiparallel to your coil like in a monkey design, clamping it's voltage spike under ten volts, so probably I've missed smg... Are you trying to tell us that a diode you used have a forward drop of 150V conducting 200A of current?! Oh, sorry, I've missed half of the thread... :)
Interesting idea about the thin wire inside the main coil!!! If it will be connected antiparallel to the main coil with a diode, then current flowing through it will lower inductance of the main coil and will cause current spike which will lead to faster heat dissipation and cancelling of suckback force. That's a smart trick. Howheter, I.m not sure about voltage which will be generated over this "secondary" coil during the energizing of the main coil...
Registered Member #1525
Joined: Mon Jun 09 2008, 12:16AM
Location: America
Posts: 294
Yandersen wrote ...
- Um, I thought the bunch of diodes are stacked antiparallel to your coil like in a monkey design, clamping it's voltage spike under ten volts, so probably I've missed smg... Are you trying to tell us that a diode you used have a forward drop of 150V conducting 200A of current?! Oh, sorry, I've missed half of the thread... :)
Can't stop laughing at "myself"! :) Is it what you have been doing for all those monthes instead of get your cg finished? Thanks, Saz. Would you put "Yandersen is against monkey-design!!!" in bold red letters over this pic so I can troll you guys every time I see antiparallel damper diodes? Would be totally epic. :)
Registered Member #1525
Joined: Mon Jun 09 2008, 12:16AM
Location: America
Posts: 294
Yandersen wrote ...
Can't stop laughing at "myself"! :) Is it what you have been doing for all those monthes instead of get your cg finished? Thanks, Saz. Would you put "Yandersen is against monkey-design!!!" in bold red letters over this pic so I can troll you guys every time I see antiparallel damper diodes? Would be totally epic. :)
LOL! I'm glad you like it. Yes it absorbed some time this morning when I could have been sawing some piece of metal.
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