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My first solid state tesla coil

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ShadowSpark

Sun May 19 2013, 02:08PM

Registered Member #16605 Joined: Wed May 08 2013, 02:09AM
Location:
Posts: 12

Hello I have recently started building a solid state tesla coil...well the coil, primary and secondary and i have been having some trouble finding the frequencys with an ossillascope I watched some youtube videos and there were helpful a little bit but diden't awnser all my questions. For example i did the same thing twice on finding the secondary frequency and got 2 different results one was near the calculated frequency the other was not and the primary frequency was just a bust i diden't have a resistor and am not going to have a spark gap so the video was useless. so does anyone have any advice on what i should do?

Mads Barnkob

Sun May 19 2013, 04:40PM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

Hello ShadowSpark

Are you building a SSTC or a DRSSTC?

If you are building a SSTC, there is no reason for you to know the resonant frequency of the secondary circuit as it does not really matter for the operation except that the driving circuit has to be able to drive at that frequency. The primary is dumping energy into the secondary from a feedback that is the frequency of the secondary, thereby it is a selftuning circuit.

If it is a DRSSTC you have two tuned circuits that needs to be the same frequency when loaded down by making sparks. This usually means that you adjust your primary frequency to be a little lower than the secondary frequency as the spark will lower the frequency of the secondary circuit and thus hitting the primary frequency if you have hit the right spot.

This is a good collection of tools to calculate the basic parameters of a tesla coil:

Here is a complete calculator to tune your tesla coil, find primary tap, simulate resonant capacitor size, experiment with different coil and topload sizes. Don't give up if you find JAVATC confusing at first, read the help tips and get to know it, this is a valuable tool that will help you from now and on:

HV Enthusiast

Sun May 19 2013, 05:33PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
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Posts: 3068

Welcome to the group.

To measure your secondary / toroid frequency with an oscilloscope just do the following:

1. Hook up a frequency generator to the base of the secondary through a series reisistor. 1k ohms usually works fine.

2. Hook up oscilloscope to the secondary side of the 1k resistor and to the RTN (GND) of the function generator.

Vary the function generator until you see a voltage dip. (I think its a voltage dip for series resonance) That voltage dip is your resonant frequency.

Of course, i could be backwards and it may be the voltage peak. Can't think straight this lazy sunday afternoon.

ShadowSpark

Sun May 19 2013, 06:52PM

Registered Member #16605 Joined: Wed May 08 2013, 02:09AM
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Posts: 12

I was planning to build a drsstc as i wish to make it play music and be quite large. if this can be done simpler with a sstc please explain as id like to know. and i do not have theese resisters nor do i know whare to get them unfortunatly and yes it would be a voltage peak.

Physics Junkie

Sun May 19 2013, 07:58PM

Registered Member #7267 Joined: Tue Oct 16 2012, 12:16AM
Location: Detroit, Michigan
Posts: 407

you could have came up with two different resonant frequencies if you or any other objects were physically close to the toroid/secondary (about 4ft or closer usually will effect your reading). An sstc will not have nearly the magnificent spark output than a drsstc, but an sstc can be made to produce much better quality music. First decide what you want more, large musical sparks or small musical sparks.

Also, when you say you want it to be quite large, how large do you mean? what power levels do you think you will be working with?

ShadowSpark

Sun May 19 2013, 10:09PM

Registered Member #16605 Joined: Wed May 08 2013, 02:09AM
Location:
Posts: 12

ill post a picture of it later to show the size and id really prefer large musical sparks

odd im not able to post pictures

question i have. I was trying to run my new coil off of the system i run my old coil on hoping id get somthing out of it and i ended up with the most screwed up thing of all arcs coming from the secondary to other points on the secondary and some going from the torrid to secondary ...it was really weird. i understand that its because there different systems but how can somthing so weird like that happen?

[Edit: Triple post]

Physics Junkie

Mon May 20 2013, 04:55PM

Registered Member #7267 Joined: Tue Oct 16 2012, 12:16AM
Location: Detroit, Michigan
Posts: 407

Sounds like racing sparks to me, usually has to do with coupling coefficient and sometimes really bad tuning.

ShadowSpark

Mon May 20 2013, 05:13PM

Registered Member #16605 Joined: Wed May 08 2013, 02:09AM
Location:
Posts: 12

so if its not the fact that the systems not meant for it then how do i fix it?

Physics Junkie

Mon May 20 2013, 07:20PM

Registered Member #7267 Joined: Tue Oct 16 2012, 12:16AM
Location: Detroit, Michigan
Posts: 407

I dont know what you you mean by the systems not meant for it. Sorry if I misunderstood you. Are you just swapping the secondary out for another one? If you could provide more details on your system parameters and or pictures then it will be easier to help you.

Assuming you are having racing sparks, try raising the secondary up in increments of a half inch until your problem goes away.

Is your primary a flat pancake style? What are the params for your primary and secondary? How high does the secondary sit from the lower most turn of the primary?

ShadowSpark

Mon May 20 2013, 08:05PM

Registered Member #16605 Joined: Wed May 08 2013, 02:09AM
Location:
Posts: 12

what i mean is i took the 2 wires from my old tesla coil and hooked them to the primary of the new one hoping to just do a test to see how it would work before i made the new one solid state and i tried that i had the secondary 3 almost 4 inches above the primary and it made no difference at all. and yes its a flat primary the secondary is about 50 inches tall with around 3000 turns on a 6 inch pipe the primary is copper tubeing with 10 turns and ill try again to post a picture last time it wouldent post

20130519210205

wow that came out really big ...wow

[Edit: Oversized picture]

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