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Re: flashover

Hi Herwig,

	I would put the insulator ring further away from the seconcady were the
field stregth is less.  Thus letting the air and distance do most of the
insulating work.  Insulators have different dielectric constants than air
so they sometimes do strang things in high E-fields.  So my vote would be
for the 6 inch ring.



At 08:06 AM 1/4/1980 +0100, you wrote:
>Hi coilers,
>I am about tuning my CW, DC driven VTTC = Vacuum Tube Tesla 
>Coil. V plate = 10 kV, primary coil = 36 turns of AWG 7 stranded 
>wire on 6" form, secondary coil = 1300 turns of AWG 26 on 4" 
>form, toroid 1" x 5"
>Today the secondary was hit for the 3rd time by a flash from the 
>primary, starting under an angle of about 45 deg from the 
>uppermost turn. Luckily the secondary was not fried, but in order to 
>avoid this, I'm about to rewind the primary to a 8" form.
>Now my question to the experienced coilers:
>To protect the secondary furthermore, I'm intending to add a PVC 
>or acrylic (appearance) tube between the two coils. I could use a 5" 
>tube (wall 0.15" thick), which is closer to the secondary or a 6" 
>tube (wall 0.18" thick), which is closer to the primary. Which 
>solution would protect my secondary best taking into consideration 
>the E-field distribution?
>Thank you for your advice,