Re: TV vs Hair Dryer ?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Mike Tucknott" <michael.tucknott-at-virgin-dot-net> 

Hi Terry

I had the same sort of event the other night.

I was in the garage running up our maggie for a demo for Steve Bell
and when we came back inside my girl friend told me she could hear
the coil running as the sound was coming from my PC speakers.

Now my PC was off and my PC sound system was also off, as my
girl friend gets to see and hear the coil running quite often she could
tell straight away what the sound was.

No damage was done to the PC or the sound system... She did say
that it was quite clear.

The more I play around with coils the more questions they bring up.

Cheers Mike Tucknott

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Sunday, September 28, 2003 12:18 AM
Subject: Re: TV vs Hair Dryer ?


 > Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>
 >
 > Hi Christoph,
 >
 > At 12:09 AM 9/28/2003 +0200, you wrote:
 > >Hello all!
 > >
 > >Today I came around some strange occourances during running my
 > >TC.
 > >I coil indoors, but the room's walls an ceiling are heavyly steel
 > >reinforced and with a good ground and some improvements I had
 > >never problem with the phone / TV / radio or computer running
 > >while the coil was running.
 > >Today I did some short runs and my mother complained that her
 > >hair dryer made strange noises like the TC itself during these
 > >runs when she was using it upstairs in the bathroom.
 > >Has this ever happened before? I feel there is anything bad going
 > >on, but why don't the more sensitive devices like the TV set
 > >react.....might the grounding for the bath mains be interrupted?
 > >I use a Siemens 20A 240V line filter and thought this would be
 > >sufficient.
 > >
 > >Any suggestions?
 > >
 > >regards
 > >
 > >Christoph Bohr
 >
 > I assume the hair dryer is just resistive elements and a common fan.  No
 > microprocessors or LCD displays...  I note that some capacitors now have
 > uPs and LCDs :-p
 >
 > First thought is that the coil is dropping the AC line just a little
 > bit.  Say 2%.  2% does not matter, but you may be able to "hear" that in
 > something that is AC voltage sensitive like the dryer.  It could be acting
 > as an audio speaker.  I bet that is it.  No problem at all there.
 >
 > Another thought is that the sound of the coil is traveling around the
house
 > (air vents, tile bathroom walls, and all) along with just getting out of
 > the shower, with the dryer going...  Just a complex accustical
 > thing...  Maybe that part of the house has a mechanical resonance at 60
 > (50) Hz...
 >
 > If you are grounding to the house water pipes...  Hmmm....  Maybe
something
 > there???
 >
 > Cheers,
 >
 >          Terry
 >
 >
 >
 >
 >