[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: center tapped transformers

Original poster: "Qndre Qndre" <qndre_encrypt@xxxxxxxxxxx>

Sounds plausible. So the center tapping is done to reduce leakage current or it's simply the only way of handling this voltage without using more expensive equipment?

----Original Message Follows----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: tesla@xxxxxxxxxx
Subject: Re: center tapped transformers
Date: Thu, 03 Nov 2005 15:56:49 -0700

Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>

Galvanically isolated, but certainly not AC isolated. There's significant capacitance from windings to core. Let's say, for grins, its 1 nF... At 60 Hz, that's about 2.6 Meg impedance, which sounds like a lot, but at 7.5 kV, that would be about 2 mA of current flow.

At higher frequencies (like, say, 120 Hz, from the break rate of a gap), the current could be even higher.

"real" isolation transformers have a metallic shield between windings and core for just this reason.




From the glorious pupman archives:
http://www.pupman.com/listarchives/2001/October/msg00752.html Discussion of RF stress

http://www.pupman.com/listarchives/1999/June/msg00046.html Measurements of C from bushing to ground, cites 2nF for a 60mA NST.

http://hot-streamer.com/TeslaCoils/MyPapers/NSTWindingStress/NSTWindingStress.html some tests by our moderator