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Re: Current Limiting and Impedence



Original poster: "Dr. Resonance" <resonance@xxxxxxxxxx>




145-160 turns will work well with a pig. It will give you approximately 140-150 mH which is the inductance required to limit your current in the 30 amp range with a 3 x 4 inch cross section of Supercil C-10. Works good with a .05 to .06 uF capacitance value.

Dr. Resonance


> > I dont think the 160 turn ballast would Saturate ,as long as I have a 'gap' > , I really, really appreciate your help/ideas, but, all this math is > WAY over my head ,....the original 150-160 turn idea came from a man that > makes transformers/inductors for a buisness , ...he said to keep the turns > down a bit , or , it may saturate,.... heck, I dont know !! Lots of turns > , BIG air gap , Few turns, Smaller air gap,.....Brett , at Precision > Transformer in Ft C helped me out when I went up there to pick up my #12 > wire ,....493-9094, (2506 Zuric Dr #5 )............ > > > > >From: "Tesla list" <tesla@xxxxxxxxxx> > >To: tesla@xxxxxxxxxx > >Subject: Re: Current Limiting and Impedence > >Date: Thu, 12 May 2005 10:28:10 -0600 > > > >Original poster: "Gerald Reynolds" <gerryreynolds@xxxxxxxxxxxxx> > > > >Hi David, > > > >You can put your ballast inductor directly across your variac and > >plot the current as a function of the variac's output voltage. and > >see how linear it is and if it saturates. The impedance of the > >inductor will be Xp = Vp/Ip (assuming the resistance is negligable). > > Choose a Vp,Ip pair for where you intend to operate it at. > >Assuming your ballast does not saturate, you can transfer the > >primary ballast impedance to the secondary by multiplying it by the > >turns ratio squared. Xs = Xp * N^2. Cres can then be calculated as > >follows: > > > >Cres (nf) = 10^9 / (2*pi*freq*Xs) > > > >If both of your ballast configurations limit the current at 14 amps, > >the effective inductance should be the same and where you are > >relative to charging resonance will depend on your Cp. This assumes > >no saturation. If the 160 turn ballast saturates, its effectivce > >inductance will go down. > > > >Gerry R. > > > > > > > >>Original poster: "david baehr" <dfb25@xxxxxxxxxxx> > >> > >> > >> > >>Ok, I had trouble when I substituted a static spark gap with a > >>SRSG , would not operate correctly ,....it was suggested that my > >>home made ballast( gapped 'E' and 'I' core ) was resonating with > >>the ballast, and,I should add more turns to the ballast. Now, just > >>say I wanted a short circuit value of 14 amps , would there be a > >>diff in resonance if I had 270 turns at 14amps , but having to > >>remove the 'I' completly from the 'E' to reach that value , or , to > >>have 160 turns , but having the 'I' shimmed about .06" to reach the > >>14amps Im lookin for ??? ....between these two configurations , > >>would they still have the same resonances with the cap or ??,,,,,, > >>Heck , I dont know !!!! > >> > >> > > > > > > > > > > >