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Re: Inducing Voltage In Metal Object Close To A TC. Was RE: FirstLight at Last! (update)

hello,

 will this work ground the case and put a shield around the motor made of
copper

    kid-kv



> Original Poster: "William Parn" <parn-at-fgm-dot-com> 
> 
> 
> Greetings,
> 
>> -----Original Message-----
>> From: Tesla List [mailto:tesla-at-pupman-dot-com]
>> Sent: Friday, April 14, 2000 9:25 AM
>> To: tesla-at-pupman-dot-com
>> Subject: Re: First Light at Last! (update)
>> 
>> 
>> Original Poster: "Bert Hickman" <bert.hickman-at-aquila-dot-com> 
>> 
>> Mark,
>> 
>> Not clear just why it chose to break down at the thermostat, but that
>> apparently was the "weakest link" at the time. However, the point still
>> remains that you're picking up enough voltage to cause breakdown in this
>> circuit, either through magnetic induction from the close proximity of
>> the TC primary winding, or from the near field of the TC in the wires
>> going between the motor and the variac in your control box. BTW,
>> near-field pickup can ALSO couple into your house wiring if you happen
>> to use house wiring in the area near the coil that's not contained
>> within metallic conduit, or if you have nearby large sections of
>> conductive metal (such as aluminum siding) that are not grounded. Some
>> coilers on this list have actually started small fires due to induced
>> voltage and arcing... :^)
> 
> I have my static spark gap sitting in a 2 foot diameter by 1 foot length
> of aluminum tube.  The open end is flush with my garage floor and then
> I also have a metal sign on top of the other open end.  The idea was to 
> help prevent RF from bugging the neighbors.  Initially I didn't have this
> connected up to ground, and being as my garage floor is not as perfectly
> level as the aluminum tube there are some air gaps down by the floor.  I
> noticed that sparks were jumping between the concrete floor and the 
> aluminum tube.  I didn't really know why so maybe what was going on
> was the induced voltage from the Megnetic field of the TC.
> 
> Very interesting thanks for sharing that information, I need to 
> come up with something better for containing the UV and RF of my
> spark gap.
> 
>> 
>> To fix your motor problem, you may want to add a couple of 600 volt (or
>> better) bypass capacitors between each motor lead and the case of the
>> motor to bypass induced RF around the windings, and use a similar
>> approach on the controller end. Other coilers have successfully used EMI
>> line filters (internally, a combination of coupled inductors and bypass
>> caps) to do the same thing. Also, try wiring the motor with a pair of
>> wires close together (like regular 120V. zip-cord), and also try to
>> route these wires so that they are short, and at a right angle to the
>> primary wiring - this should reduce the magnitude of direct inductive
>> coupling from the primary. Finally, if you still have problems, you may
>> need to physically increase the vertical distance between the motor and
>> the TC primary above. 
>> 
>> Safe coilin' to you, Mark!
>> -- 
>> Bert Hickman
>> Stoneridge Engineering
>> http://www.teslamania-dot-com
>> 
>> 
> 
> Cheers,
> Bill Parn
> 
> 
Regards