RE: TC Spark Energy

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

Original poster: "Malcolm Watts" <m.j.watts-at-massey.ac.nz> 

On 11 Mar 2004, at 22:56, Tesla list wrote:

 > Original poster: "John H. Couture" <couturejh-at-mgte-dot-com>
 >
 >
 > Malcolm -
 >
 > Note that it is the energy in the spark that we are after not voltage.
 >
 > Efficiency = energy out/energy in
 >
 > The problem is to find the energy to produce a spark of a certain
 > length with a certain TC of a certain design.
 >
 > John Couture

When you are talking spark length, voltage is most certainly one of
the dependencies. 1J at a voltage of 1V is not going to produce a
terribly long spark. Neither for that matter is 1MJ. One of the expts
I suggested to Marco should help in determining just how important
voltage is beside the other factors, particularly in repetitive
operation.
     A low capacitance (read "small") coil pumped with 1J can be made
to produce the same voltage and single shot sparklength as a much
larger, higher capacitance coil fed with 10J.

Malcolm

 > -----------------------------
 >
 >
 > -----Original Message-----
 > From: Tesla list [mailto:tesla-at-pupman-dot-com]
 > Sent: Thursday, March 11, 2004 9:27 AM
 > To: tesla-at-pupman-dot-com
 > Subject: RE: TC Spark Energy
 >
 >
 > Original poster: "Malcolm Watts" <m.j.watts-at-massey.ac.nz>
 >
 > On 10 Mar 2004, at 17:00, Tesla list wrote:
 >
 >   > Original poster: "John H. Couture" <couturejh-at-mgte-dot-com>
 >   >
 >   >
 >   > Dr. Resonance -
 >   >
 >   > As you know the topic of TC spark energy has been discussed before
 >   on > this List. Little progress was made because of the confusion
 >   over the > difference between power and energy. The TC spark energy
 >   test is very > simple, only an input wattmeter and tape measure are
 >   required. The > operation is continuous and the same as typical TC
 >   operation. Just add > a wattmeter at the input and measure the spark
 >   length. > > Because the operation is continuous the wattmeter
 >   (power) indicates > watts per second (energy). All you need is the
 >   number of sparks per > second to find the number of watts seconds or
 >   energy per spark. The > number of equal sparks per second is not an
 >   easy number to come by. > However, it can be determined provided the
 >   coiler adjusts the TC spark > output to give 120 equal spark lengths
 >   per second (for 60 Hz). The > spark should be horizontal and to a
 >   suitable ground. > > In my test I adjusted the variac to get a
 >   continuous wattmeter reading > of 120 watts or watt seconds. The
 >   sparks were adjusted until the spark > was continuous and of equal
 >   length at 120 sparks per second. Energy = > watt seconds = joules. >
 >   >     Joules per spark = 120 joules/120 sparks = 1 joule per spark >
 >   > The spark length was measured and found to be 8.5 inches. This
 >   then > gave me a Tesla coil rating for my Tesla coil of 8.5 inches
 >   per joule > of energy. > > It is obvious from the above that if the
 >   wattmeter had indicated 175 > watts with a 10 inch continuous spark
 >   and at 90 sparks per second the > TC would be rated > >       175/90
 >   = 1.94 joules per spark > >       10 inch/1.94 = 5.16 inches per
 >   joule. > > This TC would have been less efficient because it is
 >   producing less > spark length per joule of input energy. All very
 >   simple. So why is it > that coilers have seldom rated their TCs this
 >   way?
 >
 > Because the length of spark per JOule is highly dependent on the coil
 > design. Pumping 1J into a high-C secondary is not going to give the
 > same sparklength as pumping 1J into a low-C one is it? Just for
 > starters, the output voltages will be quite different.
 >
 >   > The answer is also very simple. This rating method gives low
 >   ratings > for large TCs,  only a couple inches per input joule. In
 >   other words > large TCs appear to be very inefficient. This is a
 >   problem. Any > comments?
 >
 > I fail to see what the voltage developed by 1J into a small
 > capacitance vs the voltage developed by putting 1J into a large
 > capacitance has to do with efficiency.
 >
 > ?
 > Malcolm
 >
 >
 >