> The LC-102 can also generate as much as a thousand volts for measurement
> of leakage current. So I put 1000VDC (the capacitor is rated for 3500
> volts) across the air variable and measured leakage current thru it. The
> value of leakage current varied ranged between 1 and 2 microamps as I
> turned the rotor. Leakage current seemed to be slowly increasing as
> time passed. What is typical leakage current for this type of capacitor?
> What is the leakage path? Can the leadage be reduced/eliminated? Or,
> more to the point, should I be concerned with this level of leakage
> current? As a comparison, I had three other air variables (including two
> big transmitting air variables of the type used in Johnson KW
> Matchboxes) that measured zero leakage under the same test conditions.
>
> Advice?
As I mentioned in a previous post: Is the capacitor clean? Are any of the
plates bent, or have nicks?
Spray it with "Simple Green", let it set for a few minutes, and then run it
through the dishwasher a couple of times. Let it dry completely and test it
again.
1 to 2 microamps is way too much leakage for a 3500 volt cap.
Leakage should be measures with the plates fully engaged.
Leakage will increase considerably if there is dirt and grime on the plates
or the end-caps.
73, Barrie, W7ALW
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|