[RFI] Elimination of Treadmill RFI on 160 meters

[Christopher Brown]

Looking at the picture I am a bit concerned about a potentially serious
safety issue.

Brick filters like the Delta shown have a pair of line terminals (does
not matter which is hot and which is neutral so long as you keep it
straight) but the safety ground terminal bonds to the metal case of the
filter body.

The filter body in turn is meant to be bonded to the chassis of the
equipment it is installed in.

I could be wrong, but based on the picture you appear to have neutral
and safety ground on the equipment side connected to the neutral
terminal of the filter.


This can present a serious hazard, as the green wire bonds to the
chassis of the treadmill...  Should there be a neutral fault anywhere
upstream of that filter and the chassis of the treadmill would go hot
with full line voltage.

For exactly this reason, NEC allows only ONE neutral to safety ground
bond AT the primary disconnect.  Otherwise, failure of a neutral
conductor puts voltage on the chassis and creates a shock hazard.


On 1/8/15, 4:11, Don Kirk wrote:
> For many years my wife's treadmill caused strong interference on 160 meters
> when it was in use, and yesterday I was able to completely eliminate the
> RFI using a combination of two different filters.  I created a simple
> website that documents my tests and the filters used, and for those
> interested the website URL is http://sites.google.com/site/treadmillrfi/
> 
> The website contains a link to a video on youtube where you can actually
> see the effectiveness of the filters.
> 
> 73,
> Don (wd8dsb)
> _______________________________________________
> RFI mailing list
> RFI at contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
>