Re: [TCML] Need info help Model M-150 Tesla Coil from late D.C. Cox.

[jhowson4@xxxxxxxxxxx]

Hey, 

I am not familiar with DC's coils personally, 
But i ran your numbers through Java TC and from what you have given us, the coil apparently tunes ar 3.5 turns on the secondary or in that area. according to the data you have given. But pre my below querys, i am not sure if the 3.5 is right. 
http://www.classictesla.com/java/javatc.html 
When i tune my coils i set up a break out point on the toroid (hunk of wire sticking out the side) and a large vertical peice of Al foil some distance away. start with it close, and run the coil on low power, so you see little sparks? 
if you do you can be reasonably sure that you have everything wired right. 
Then just move the tuning point around until those sparks look the best, while it is off of course . 
increase the power move the foil and do this again. You should have gotten it pretty close on the lower power, but when the arcs are large, it changes it slightly, so just mess with this tap point until you get the best looking sparks. 
Then remove the break out point, repeat, It should be pretty set at this point though. 
At full power you should get good sparks without the break out point. 


You are saying that the inner turn of the primary is inside the secondary, 17" dia vs 11.5" dia 
Which I am thinking is unlikely as I have never heard of a coil being that way. 
So i am thinking you might have mistyped something there which would make a difference in the capculations. . 

I also noticed that you specify a 40" secondary with 4+1=5" inches being uncovered. but you specify the winding as 35.5". 

The capacitor is probably a compact array of C DE 942C20P15K's as if I recall DC liked to use those. 
But it also could just be a maxwell inside a box to make it look nicer and protect people in case it were to ever explode. 



best of luck, 
John "Jay" Howson IV 


"Why thank you, I will be happy to take those electrons off your hands." 

----- Original Message -----
From: "Mike DeLosier" <mdelosier@xxxxxxxxxxx> 
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx> 
Sent: Monday, October 15, 2012 8:34:01 PM 
Subject: [TCML] Need info help Model M-150 Tesla Coil from late D.C. Cox. 

Hello, 

I am currently working a Resonance Transformer Model M-150 Tesla Coil 
1,000,000 volt unit, 
It said it develops 8-9 foot long sparks with minimal input power 6-7 
kVA . 

The late D.C. Cox built this Tesla Coil for the museum and didn’t 
install it or complete it they received shipment in Feb 2012. 

I am volunteering to get the M-150 Tesla Coil into operation at the 
Museum as an exhibit. 

I looking for some one who has M-150 Tesla Coil or knows about it, D.C. 
Cox seemed to have many friends over the years.. 

I have been reverse engineering it the Tesla Coil Primary, Secondary, 
Rotary Spark Gap, Control Box, Variac unit and H.V. power supply.. 

I now have schematics I drew of complete M-150 Tesla Coil wiring end to 
end. 

My questions are the Coil Design, Resonance, Tuning, operation and 
duration of operation. 

Today I debugged the last of the wiring problems from the Variac unit to 
AC Voltage Meter. 


After tracing the wiring out over several evenings we powered M-150 up. 

Didn’t apply full power yet, 

Initial power up and check out of control box, OK 
Initial check out rotary spark gap all is OK, 
Initial check out of HV power supply: 

230 VAC Input H.V. Output no load, ( no coil or spark gap 
). 
50 VAC 2.9 KV 
100 VAC 5.71 KV . 
150 VAC 8.68 KV 
200 VAC 11.67 KV 

We then powered up M-150, but not to full power no output sprites from 
top load break out wire. 

I think there is a tuning issue and or re-design issues, the coil 
secondary turns is only 350 turns, D.C. Cox had it shorten by two feet 
and maybe not adjusted into tune. 

Toroid terminal is 33" x 8" = 35.6 pf 

Secondary Coil: 
350 turns of 18ga stranded red pvc jacket. 
17" coil dia. 
Total secondary tube length is 40" 
Actual winding length 35.5" 
Wound with 18ga stranded red covered pvc wire. 
Winding starts 1" from top end' 
Winding ends 4" from bottom end. 
40" X 17" dia sonotube covered with looks like Dolph's AC-43 

Primary Coil: 
8 Turns of 1/2 copper tubing. 
Minor dia 11.5" 
Major dia 19.5" 
Winding Type Copper Tube 1/2" 
Winding Spacing 1" 
Primary base 4' dia of 1" wood plywood or particle board. 

Primary Capacitor 0.1 uf and 80KV 

Capacitor is a mystery white box as picture shows, there are two one 
connect and one not. 
On cap says 0.1uf @ 80KV, I may open the white box, Maxwell’s or home 
maid caps? 

18” dia 10 point rotary spark gap ran by 1725 RPM ½ hp motor 

350 secondary turn seems to be vary short of the 1 million volt output. 

I have also taken several pictures of M-150 Tesla Coil, HV Power Supply, 
H.V. output Variac and Main Control Box. 

Any insight on the M-150 would be appreciated :-) 

I have done the math on coil specs, seems to be a problem? 

Tomorrow I bring my scope, freq generator / counter double check 
resonance freq to math and a capacitance meter to check the un-marked 
mystery caps capacitance too. 

Thanks 
Mike DeLosier 
mdelosier@xxxxxxxxxxx 


_______________________________________________ 
Tesla mailing list 
Tesla@xxxxxxxxxx 
http://www.pupman.com/mailman/listinfo/tesla 
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla