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Re: Doorknob Caps

Subject:  Re: Doorknob Caps
  Date:   Wed, 11 Jun 1997 19:48:00 +0000
  From:   "John H. Couture" <couturejh-at-worldnet.att-dot-net>
    To:   Tesla List <tesla-at-pupman-dot-com>


At 05:32 AM 6/11/97 +0000, you wrote:
>Subject:   Re: Doorknob Caps
>  Date:   Tue, 10 Jun 1997 22:51:08 +0500
>  From: "Alfred A. Skrocki" <alfred.skrocki-at-cybernetworking-dot-com>
>    To:  Tesla List <tesla-at-pupman-dot-com>
>
>
>On Tue, 10 Jun 1997 05:41:49 +0000 wrote;
>
>
>>  Power factor losses? Do you mean high power factor means high losses?
>> 
>>  How do you determine losses using the power factor?
>
>When you apply R.F. do a dielectric as in a capacitor, the dielectric
>will absorb a percentage of the R.F. and dissipate it as heat and 
>this dissipation is inversely proportional to the power factor of the 
>dielectric. For example Mica has about the lowest power factor 
>(0.0001) of all the available dielectrics and it consequently has the 
>lowest losses from R.F. absorption, next to Mica is Teflon with a 
>power factor of 0.0002 and then we have Polyethylene at 0.0002 
>to 0.0005. a really bad dielectric would be Cellulose Acetate with a 
>power factor of 0.01 to 0.1 it will melt down rapidly under R.F. due 
>to it's high absorption of R.F.
>
>>  The last I heard losses were resistive in capacitors or inductors.
>
>I would think the resistive losses in a capacitor is going to be 
>insignificant, the reactance losses are another story, remember 
>were dealing with A.C. Your also forgetting that inductors also have 
>hysteresis losses.  
>

  Alfred -

  I received your answer before I got my posted question on the List?

  Dielectric dissipation is resistive loss (heat)
  RF absorption causes resistive loss
  Melt down requires heat (resistive loss)
  Resistive losses in capacitors are always significant in Tesla coils
  Reactance losses - what do you mean? 
  All losses in reactors are resistive
  Hysteresis losses are resistive losses

  Note that dissipation loss and dissipation factor are two 
  different parameters.   

  The dissipation (resistive loss) in a capacitor is DIRECTLY 
  proportional to the power factor. The dissipation FACTOR is
  inversly proportional to the power factor.   

      Watt loss = VA cos (a)           cos (a) = power factor

      Watt loss = resistive loss R     PF = W/VA = R/VA

  

  If the power factor (decimal 0 to 1) increases the wattage
  (resistive losses) increase. If the angle (a) (0 to 90)
  increases the cosine and the resistive losses will decrease.   
   
  Your comments are welcomed.   

  John Couture