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Registered Member #1107
Joined: Thu Nov 08 2007, 10:09PM
Location:
Posts: 792
Today i scored a mo in the trash so now i want to make a resonant mot supply. Im new to these so i need a little help and have a couple of questions.
1. do the 2 mots have to be identical 2. do the resonant caps have to be identical
here are the ratings on the moc's .8uf 2000wvac and .67uf 1600wvac and .65uf 2100vac I have 3 mots and 2 of them look almost identical in power rating.
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
Yes they don't have to be the same and you will need 4 caps. You can also make big arcs with just 1 MOT and 3 caps (all caps in parallel, and in series with your arc).
Registered Member #1438
Joined: Sat Apr 12 2008, 12:57AM
Location: Canada
Posts: 218
When I finally set up my resonant, it worked great, making a foot long arc but after two minutes of operation, a loud slapping noice could be heard. I stopped and checked out the MOC's and the MOT and everything seemed normal. I powered it up again and it worked normal until I heard the same noise. I have no idea on what the problem is.
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
hydraliskdragon wrote ...
When I finally set up my resonant, it worked great, making a foot long arc but after two minutes of operation, a loud slapping noice could be heard. I stopped and checked out the MOC's and the MOT and everything seemed normal. I powered it up again and it worked normal until I heard the same noise. I have no idea on what the problem is.
Firstly try to space your caps' metal cans so they dont touch. Maybe they are sparking internally.
It is also possible that your MOTs are overheating and causing decreased insulation voltage stand-off capability. Check the temperature of the windings (by your finger, if you burn it you know it is too hot )
Registered Member #1438
Joined: Sat Apr 12 2008, 12:57AM
Location: Canada
Posts: 218
Thanks everyone for the input. I checked the MOT's primary and secondary tempurature but it only rose about 7ºC higher, but I found out what the problem was. While I was making arc's, a huge spark jumped from the canister of the capacitor, to my HV end. I re-organized the caps and the sound went away.
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resonant mot?
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