From: boris petkovic
Date: Wed, 1 May 2002 04:07:39 -0700 (PDT)
Subject: Re: [TSSP] Secondary voltage stress factor
Bert,All, (regarding racing spark problematics) I'm not very optimistic in determining its start by simulation nor possibility for discovering all the critical factors that enable the phenomenon. Currently,we can simulate (quite accuratelly asuming no losses or known primary losses) transient response of secondary given coupling and typical system geometry --->Voltage time-space function. But despite relatively low critical voltage gradient condition Bert reffers to,I'm not convinced ideal clean dielectric will show start of racing spark before somewhere ,at some point in time critical surface E field strenght reaches ~26-28 Kv/cm. Whatever be the main reason of racing spark creation in that case ,it may travel latter in much less intensive fields without problems. Even if we knew the exact parametrs desribing the process there's lack of satisfaction with present E field simulations in very surface of coil coating. Since two resonators of same height H,but different diameters D with same Vtop and even same voltage profiles may have Emax different on their coating surface,field simulator is necessary (E=grad(V) in space coordinates). Programs like E-Tesla field introduce more error as point in space gets closer to a resonator surface.This must be especially true for thin coating and small wire diameters. Dielectric "memory" of coil form and coating togather with amount of coupling is another factor that contributes to local field increase. I have no idea how to deal with this problem becouse it varies from case to case. Let alone all said ,what to say about surface charges coming from a nearby top electrode ion cloud during longer runs? Treat that right and with good preceison,and substitute yourself among gods. Regards, Boris __________________________________________________ Do You Yahoo!? Yahoo! Health - your guide to health and wellness http://health.yahoo.com
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