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Two DRSSTC Coils as twin system - run out of phase.

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Dzejwor

Sun Jun 13 2010, 06:36PM

Registered Member #2750 Joined: Sun Mar 21 2010, 08:47PM
Location: Poland
Posts: 46

Hi I have two identical DRSSTC's and I want to run out of phase and made sparks betwen coils ... but now they are don't want to conect together on the contrary can be said that even they do not like each other

. When I move coil's closer I have smaller sparks. I drive coils with one interrupter they are start work at the same time. I think I need to reverse the phase in one of the coils but is it enough ? Maybe I need to build interrupter where I could change the phase of the signals triggering the coils ? How Steve and Jeff do this on this movie ?

Gregory

Sun Jun 13 2010, 09:40PM

Registered Member #2922 Joined: Sun Jun 13 2010, 12:08AM
Location:
Posts: 226

the bases of the secondaries are connecteds together?

Goodchild

Mon Jun 14 2010, 01:47AM

Registered Member #2292 Joined: Fri Aug 14 2009, 05:33PM
Location: The Wild West AKA Arizona
Posts: 795

Ok keep in mind I have never tried to run my DRs out of phase but if I was to try it, this is what I would do:

First off amusing the Fo of both coils is the same, you will need to delay the + on pulse to one for the coil by
the duration of one RF half cycle of the Fo of the coils.

In other words while one coil is in a + RF half cycle the other coil is in a - RF half cycle.

So for example say the Fo of the 2 coils is 100KHz:

1 / 100,000 = 0.00001S or 10uS period

So your interrupter has to do this:
1. Turn one coil on
2. Wait 10uS then turn other coil on

I have never tried this but this is how I would do it. Some one please correct me if I'm wrong on this.

Coronafix

Mon Jun 14 2010, 08:14AM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

Wouldn't you just reverse one of the primaries?

Dzejwor

Mon Jun 14 2010, 07:13PM

Registered Member #2750 Joined: Sun Mar 21 2010, 08:47PM
Location: Poland
Posts: 46

the bases are connected together with AWG3 wire and that wire is grounded. I reversed phase in one coil. Now I wait to good weather to made some tests.

Goodchild

Tue Jun 15 2010, 12:37AM

Registered Member #2292 Joined: Fri Aug 14 2009, 05:33PM
Location: The Wild West AKA Arizona
Posts: 795

Dzejwor wrote ...

the bases are connected together with AWG3 wire and that wire is grounded. I reversed phase in one coil. Now I wait to good weather to made some tests.

umm how do you mean revers the phase? As in the feedback or GDT? because if you did that won't work.

teravolt

Tue Jun 15 2010, 03:37AM

Registered Member #195 Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111

Hi Dzejwor, make shure that the resonant frequency is the same. the fields of each coil are in phase and canceling each other when they are moved together. they should be treated like one big half wave coil that is cut in half and placed verticaly. hopes that helps

Steve Conner

Tue Jun 15 2010, 09:47AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

I got good results by just connecting a second resonator, of roughly the same frequency, to the base of my DRSSTC. The second resonator is base-driven by the ground current of the first one, only one set of drive electronics is needed.

A problem with this approach is that the base of the master coil develops a fair amount of voltage, and can flash over to the primary. You can't ground the bases because it breaks the connection between them, so out-of-phase operation won't be forced any more.

It should also work with two driven coils, and the symmetry should be better, with less risk of flashover.

Another problem is that there are now three resonant frequencies: depending on which you choose, you can get sparks from one coil, or the other, or both. When both coils are making sparks, the sparks are necessarily in the right phase to connect with each other.

Tying the bases together cancels one of the resonances: if you ground the bases there are four resonant frequencies, and one of them corresponds to "Both coils making sparks, but the sparks avoid each other".

Dzejwor

Tue Jun 15 2010, 01:14PM

Registered Member #2750 Joined: Sun Mar 21 2010, 08:47PM
Location: Poland
Posts: 46

As usual, it is not as easy as it seems

I rversed phase by reversing pins of GDT primary and reversing CTs, primary ringup proper. I have secondaries wound in oposite directions. teoretic when the primary current of both coils are in pghase secondary voltage is out of phase but this is just only teory I don't know what is in real word. Resonant frequency will never be ideal the same. I can run both primaties at near the same frequency. I dont want to run in out of phase for a long periods of time I want only to try do this. In future coils will be used primarily for paly music

Goodchild

Tue Jun 15 2010, 03:33PM

Registered Member #2292 Joined: Fri Aug 14 2009, 05:33PM
Location: The Wild West AKA Arizona
Posts: 795

OK look it's not that hard look at this scope shot of the bridge out put and primary current waveforms:
4627741312 024fe88e02 O

The bridge oscillates at the same freq as the Fo, so at one point it's + and at other times it's -
If you sent both coils the same interrupter pulses, both bridges would go + at the same time and
both bridge would go - at the same time.

All you should have to do is turn one coil on, then wait for it to swing - and then when it dose turn on the
other coil, this way when the second coil turns on the first coil is out of phase with it.

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