Re: Newby

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

Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com> 


Welcome to the group.

BTW, what city and state is Perry in?

Dr. Resonance


 > Original poster: "Michael Brooks" <mbrooks-at-perrytech.edu>
 >
 > Thank you for the input; I am very interested in creating a little
 > monster of my own.
 > As far as my background I teach Electrical Technologies at Perry
 > Technical Institue. We train students for their Journeymen Electrical
 > License. I don't have any engineering background per se (though I am
 > working on that)
 > Primarily I teach basic theory behind caps, inductors, 1 & 3 phase AC
 > generation, sine wave characteristics, transformer theory and
 > connections, 3 phase power and PF correction.
 > Some of what I have read on the list so far is well beyond the capacity
 > of my noodle at this point but I am confidant I can figure it out in
 > time.
 > Again I appreciate the information and I will continue to learn and most
 > probably patronize with many questions!
 >
 >
 > Michael Brooks
 > Instructor
 > Perry Technical Institute
 > mbrooks-at-perrytech.edu
 > 509 453 0374 xtn 234
 >
 >
 > -----Original Message-----
 > From: Tesla list [mailto:tesla-at-pupman-dot-com]
 > Sent: Tuesday, July 27, 2004 12:08 PM
 > To: tesla-at-pupman-dot-com
 > Subject: Re: Newby
 >
 > Original poster: "Paul Nicholson" <paul-at-abelian.demon.co.uk>
 >
 > Michael Brooks wrote:
 >
 >   > I have just recently signed up for the list
 >
 > Great!
 >
 > Your description of power factor correction of an inductive load
 > is essentially the same thing as occurs when a coil is tuned to
 > some required frequency by adding capacitance at the top.
 >
 > If you picture a source of AC driving into the *top* of the coil,
 > (with coil base grounded) the source will see a lossy inductive load.
 >
 > (At least it will if the drive frequency is below the lowest self-
 > resonance of the coil).
 >
 > Then adding shunt capacitance (by way of the self capacitance of
 > a toroid or sphere) to the top of the coil is having the same
 > effect as power factor correction.   The PF correcting caps are
 > forming a parallel resonant circuit with the load inductance.
 >
 > However, this doesn't reflect the way that toroid sizes are chosen
 > when coils are designed.  Instead coilers (should) choose the
 > toroid (or whatever topload shape is employed) size that best suits
 > the generation of streamers  - if that's the intended application.
 >
 > They fit this chosen topload to the coil and then look for the
 > frequency at which the power factor correction naturally occurs,
 > ie the resonant frequency of the coil/topload combination.  So it
 > is kind of like the PF correcting process in reverse - start with
 > the cap and find the frequency at which correction occurs!
 >
 >   > Is this similar of the same as the calcs you may be using to
 >   > get to reasonance?
 >
 > Yes, when you've finished calculating the PF correction cap, you
 > should find it resonates at the line frequency with the load
 > inductance, ie Xc has the same value as the Xl of the load when
 > calculated at 60Hz.  In general,
 >
 >     (Xl = 2 * pi * Freq * L) = (Xc = 1/(2 * pi * Freq * C))
 >
 > which leads to Freq = 1/(2*pi*sqrt(L*C)).
 >
 > Welcome to the list Michael - and as you're obviously involved in
 > elec eng you won't have any trouble figuring it all out.  All the
 > usual laws of physics apply (with the odd subtlety to make life
 > interesting) so your existing EE knowledge applies 100%.
 > --
 > Paul Nicholson
 > --
 >
 >
 >