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Primaries



Hi all,
       I have some questions I would appreciate some answers to.
(1) To Greg Leyh : You mentioned some figures for gap current and
    gap conduction voltage the other day. How did you measure those?
(2) To Richard Hull : Have you tried primaries with v. large L/C 
    ratios (for example, L of 200uH+). If so, how well did they work?
    Was there any improvement over say 100uH? I am assuming that
    the bang size and break rate was kept constant.   
(3) Also to Richard : Have you _ever_ measured a dynamic primary Q
    above 10?
    
    I have desgined and am construction a low frequency secondary for
a number of different experiments, several different types of systems
and also to have a crack at setting a record for around 2.3kW. I am
constantly running into a barrier with the primary and in particular 
the gap losses. It seems that this is almost the sole determining
factor of system performance and I am desperately trying to find a 
way to improve it without resorting to exotic devices. For your 
interest, resonator spec is:
    L about 140mH
    Cself around 24pF
    Winding Height 39"
    Diameter 16.5"
    Closewound with 0.9mm diameter wire
    Former = open frame (simply because I don't have any pipe).
    Predicted Fself around 87kHz
    Predicted F with around 45pF topload about 50kHz with a range
of frequencies in between for smaller toploads.

    I am currently constructing the former which is turning out to be 
a tricky exercise with the materials I have on hand.
    An analysis based on a dynamic primary Q of 10 suggests that the
lower in frequency I go, the smaller the gap losses become.
    If anyone has any input on this or comment to make I would 
welcome it. I am just about at the end of the rope with regard to the 
primary. I had hoped late last week that gap losses might reduce with
a drop in gap current but it seems that hope is doomed.

Malcolm