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Re: coax (grounding shield & AC?)



Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Matt,

What Dr R is getting at is the "Blumlein" effect. I have tried to research this and believe it is a transmission line phenomenum when improperly terminated. I dont know this definitively but believe its possible to figure it out if someone would be willing to create the effect. Presumably one would use a PIG and have a safety gap from each HV bushing to ground to protect the PIG from damage. The setting of the safety gap would be larger than usual so one would be fairly certain that any firing was due to the effect and not to the the voltages created by the TC. If we can find a volunteer, maybe Dr R can help that person create the effect based on his experience. Just an idea :-))

Gerry R.


Original poster: "M G" <gt4awd@xxxxxxxxx>

"Don't run it with AC with the grounded shield on it."

Hi, just wondering why it is not good to use the coax with grounded shield on for AC? I use coax for high voltage wire on my jacobs ladder. I did notice that if the grounding shield was left normal by the high voltage terminals of the NST it would pick up some of the electricity. A small, weak, arc on the other end of the shield would jump to anything conductive, such as your hand. Cutting the shield/coil of wire off about 1" from the terminals stopped the problem though. Is this the reason, or something else?
Thanks,
Matt G.