Dan,
Another thought that I had regarding adjustable phase controllers is that they may not be good for your capacitors. If you adjust the phase to purposely fire anywhere other than the 0 and 180 degree points for a 120 BPS system, then you are introducing voltage reversals on the capacitors. The worst case for a 120 BPS system would be if you set it to fire at 90 and 270 degrees which would theoretically yield up to a 100% voltage reversal of up to the output voltage of your NST. The capacitors would be seeing this reversal 120 times per second. We all know that voltage reversals are not good for HV pulse rated capacitors. I don't know how damaging this would be. I posted this idea previously and didn't see any response so I don't know how serious it could be.
Steve White
Cedar Rapids, Iowa
----- Original Message -----
From: "Daniel Kunkel" <dankunkel@xxxxxxxxx>
To: "Tesla list" <tesla@xxxxxxxxxx>
Sent: Monday, October 22, 2018 8:17:36 AM
Subject: Re: [TCML] SRSG strobe
Steve,
Thanks for the insight. For some reason I was thinking typical ignition
voltage was in the 10-15kv range, but it looks like you are right, I'd need
a few more KV. I did however try to trigger it with a 12kv NST and that
didn't work.
For now I am using a 3,600 RPM 1/2 HP motor with a 11.5" disc...it is
drilled for 16 electrodes...which is for future growth and pole pig
experiments. For now, I am stuck with my humble NST bank, and from what I
can remember, it seems like 120 BPS seems to be the best option for NST's.
So 240 BPS it probably not an option.
I do have a cheap oscilloscope, but it is not a two channel unit. I do want
to get the phasing dialed in as good as possible to protect the NST bank
from damage.
Thanks,
~Dan
Kansas City area
On Mon, Oct 22, 2018 at 7:15 AM Steve White <steve.white1@xxxxxxxxx> wrote:
> Hello Dan,
>
> If your SRSG is running at 240 BPS, and assuming that you have
> synchronized the spark gap properly without use of the phase controller, I
> wouldn't bother making an adjustable phase controller. I went to a lot of
> trouble to make an adjustable phase controller using a big variac and some
> motor run capacitors to vary the power supply phase to my SRSG motor. Using
> an optical sensor and oscilloscope, I confirmed that it would provide
> almost 90 degrees of phase adjustment. To my great surprise, it had no
> discernible affect on the streamer length or quality. A few others have
> also reported this when I mentioned it on an earlier thread. If your SRSG
> is running at 120 BPS, it might have an affect.
>
> To answer your question though, have you considered using an optical
> sensor and an oscilloscope, if you have one, to set the firing phase? I
> used one of those U-shaped optical sensors. I mounted it so that the flying
> electrodes would pass through the U to break the beam. You can then see the
> pulse train in relation to the 60 Hz power line on the oscilloscope and
> rotate the motor until the phase is exact. I used 2 channels on the
> oscilloscope with one channel displaying the optical sensor output and the
> other channel displaying the 60 Hz AC power line. Then you just rotate the
> motor until the pulses align with the 60 Hz sine wave at 0, 90, 180 and 270
> degrees for a 240 BPS SRSG. Be sure and use an isolation transformer of
> some type for the power line input to the scope or you could create a
> direct short circuit. I just used a small transformer that I had laying
> around.
>
> To use your automotive strobe light I think you would have to add some
> electronics to trigger it. Basically, you would need a zero crossing
> detector on the AC power line which would then trigger a high voltage pulse
> of sufficient magnitude to fire your strobe light. Remember that an
> automotive strobe light pickup coil is designed to work with 30 KV spark
> plug voltages.
>
> Steve White
> Cedar Rapids, Iowa
>
> ----- Original Message -----
> From: "Daniel Kunkel" <dankunkel@xxxxxxxxx>
> To: "Tesla list" <tesla@xxxxxxxxxx>
> Sent: Sunday, October 21, 2018 10:37:35 PM
> Subject: [TCML] SRSG strobe
>
> I'm getting ready to build my phase controller to control my new SRSG. I
> thought I've heard of others use an automotive ignition timing light to
> strobe and watch the phasing, but I can't get mine to trigger off a 60Hz
> source. Can anyone offer some advice here?
> ~Dan
> Kansas City area
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