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Re: 2 questions on resonance (fwd)


  Mike, Mark -

  Power, energy, and time periods for Tesla coils can give coilers many
headaches. To avoid errors these variables must be clearly defined and used. 

  For example, "The Average power cannot be increased". Note that average
can be either "average continuous power" or "average instantaneous power".
The equation for average power is: 
  
  Average power = P1+P2+P3+...Pn / n
        P1, P2, etc, is average continuous power or average instantaneous
power.
        n is the total number of individual samples.

  Note that time is not involved and average power can be increased or
decreased depending on the power samples. However, when equating power to
energy the time is involved and the equation is:

  Power = energy/dt
          power is in watts
          energy is in joules
          dt is usually a small fraction of a second

  "Averaging power over time to give J/S" must be used with caution because
average power can be average continuous power or average instantaneous power.

  The usual coiler equation to find the energy in the TC primary capacitor is:

   joules = .5 * Cp * Vp^2

  Note that time is also not involved with this equation. However, equating
these joules to power requires that time be taken into consideration as
shown above. Care must be taken to keep the proper time periods in the
correct order to prevent misunderstandings. When the time periods are
properly used there will be no "J/S out" greater than "J/S in" over time.
However, there can be an "average instantaneous power out" greater than
"average continuous power in" during Tesla coil operation.

  John Couture

-----------------------------

At 09:15 PM 4/17/99 -0600, you wrote:
>Original Poster: Hollmike-at-aol-dot-com 
>
>In a message dated 4/17/99 3:06:40 AM Mountain Daylight Time, 
>tesla-at-pupman-dot-com writes:
>
>> 
>>  >I appreciate we store energy in the primary cap and release this over a 
>>  >much shorter time interval, however in terms of power calculations should 
>>  >we not be averaging this over time to give J/s, and I still can't see how 
>>  >J/s out can be > J/s in over time.
>>  >
>>  >mark
>>  >
>
>Mark,
>     Your thoughts are indeed correct.  The AVERAGE power cannot be 
>increased.  It is the instantaneous power that is magnified and then followed 
>by a relatively long period of no power which over time averages to the same 
>power(not counting the resistance losses etc) as put into the system.  
>
>