Violet Ray Tesla Coil

Subject:  Violet Ray Tesla Coil
  Date:   Mon, 2 Jun 1997 17:48:55 +0500
  From:   "Alfred A. Skrocki" <alfred.skrocki-at-cybernetworking-dot-com>
    To:   Tesla List <tesla-at-pupman-dot-com>

Hi all, I purchased another hand held "Violet Ray" machine at a 
flea market over the weekend for $5.00. The unit didn't work at all 
so I opened it up and studied the insides, below is an ASCII 
schematic of what I found. Please excuse the ASCII art!

                                    |   |
    socket for evacuated tubes ---> |   |
                                      ) S
                 VG ____  _|_         )
                      | | ___C        )P
                     #( |__|__________)
                   C #(    |
                   O #(    |
                   I #(    |
                   L #(    |
                      |    |

There is an iron core coil connected at one side of it's windings to 
the line. The other side of the coil connects to a vibrating armature
almost identical to those found on the old induction coils. The 
stationary contact of the interrupter is connected to a 5 turn tesla
coil primary P made of 2 no.20 double cotton coated wires, the other
side of the primary is connected to the tesla coil secondary S which
is very fine wire (No.36 - 40) wound on a wooden form 3/4 inch in 
diameter and 2 1/2 inches long. the primary also connects to the 
moving contact of the interrupter and there is a paper capacitor C
across the vibrating spark gap VG. There is an adjusting screw that 
pushes the moving armature of the vibrating spark gap closer to or 
further away fro the stationary contact. The spring was over bent in 
the unit I purchased so I rebent it back into position. The unit then 
worked and yielded snappy thin bluish white sparks about 2 inches in 
length at the best position of the adjustable control. Sorry I can't
provide any measured values for the inductance, capacitance, voltages,
ect. but one of my kids stole my multimeter! Grrrrrr. The unit is 
about 10 inches long and 2 inches in diameter and made of black 
bakelite, it looks identical to the Tesla coil vacuum testers except 
it is designed to hold evacuated glass tubes instead of the pointed 
metal probe. The only markings on the unit were;

                     20w  115V
                      No. M66
           The Master Electric Co. Chicago

I find their use of a vibrating spark gap in series with the line 
through a choke to be interesting. Its circuit looks identical to the 
circuit described in Thomas Stanley Curtis's "High Frequency 
Apparatus" 1916 (reprinted by Lindsay Publications 1988)in chapter 
VIII "Kicking Coil Apparatus".


                              \\  ~ ~  //
                               (  -at- -at-  )
                           Alfred A. Skrocki
                             .ooo0   0ooo.
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