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Re: [TCML] First run

Thanks Gary,
I'm not sure what I was thinking. lol. I didn't use the RMS voltage when I calculated 
the number of the MOVs I needed. Guess I'll get busy removing 4 of them.

Steve
----- Original Message ----- From: "Gary Lau" <glau1024@xxxxxxxxx> 
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Sent: Sunday, November 14, 2010 2:34 PM
Subject: Re: [TCML] First run



I think you have too many MOV's.  It won't affect performance, but it won't
adequately protect.

The MOV you used appears to be a beefier version of the one that Terry
originally used, with the same voltage specs, but better power and current
specs. As you noted, the max voltage is 1465 VDC or 1000 VAC, RMS. If you 
have a 12kV RMS NST, 12 of these MOV's would just come in under the wire.
Cranking up the Variac or setting the gap just a bit too wide would violate 
the MOV spec.  So use the next even number - 14 MOV's total.

Regards, Gary Lau
MA, USA
On Sun, Nov 14, 2010 at 12:22 AM, Steve Vance <steve_vance@xxxxxxxxxxxxx>wrote:
I ran it again tonight. Everything seems to be OK now. I put an adjustable gap in series with the quick gap. The streamers didn't get much bigger but 
it got a lot louder. All it needs is a little more tuning.
As far as the Terry filter goes, I think I did it right. The varistors are 
1.8 kV. The max voltage is 1000V AC / 1465V DC. I figured it like
this...12000 X 1.414=16968Vrms / 1000=16.968 I used 18 for an even number. Was I suppose to use the max ac voltage? It looKs like the ones terry used 
were pretty close to the ones I used. The main difference is the current
surge. If he used 16 for a 15kV NST, he must have used the max DC voltage 
of the varistor in the formula. Is this how it's done?

Steve

----- Original Message ----- From: "Gary Lau" <glau1024@xxxxxxxxx>
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Sent: Saturday, November 13, 2010 10:38 PM
Subject: Re: [TCML] First run


 If the Terry filter MOV's were clipping, they would be very hot, if not

smoking.  The MOV's shouldn't be clipping anything unless the gap is
opened
too far. Since your safety gap isn't firing and assuming the MOV's aren't hot, I'd say it's good. YOu shouldn't add any more MOV's unless you know 
for sure that they're clipping at too low a voltage.

The MOV's that Terry originally specified were Panasonic ERZ-V10D182,
Digikey P7215-ND. For a 15kV NST, a total of 16 of these are needed. Any more and the protection would be compromised, and any less, and the MOV's 
will conduct and smoke all the time.  You're using a different part, so
it'll be up to you to ensure that you're using the right MOV part and the 
correct number for your NST voltage.

By saying that the output of the filter seems weak, do you know that the
coil would perform differently without it? I'd say give that a try if you 
really suspect the filter, but I doubt the filter is the problem.  More
likely the Quick gap is not properly set. That's one reason I prefer the 
sucker gap - it's a lot easier to set.

Regards, Gary Lau
MA, USA

On Sat, Nov 13, 2010 at 1:29 AM, Steve Vance <steve_vance@xxxxxxxxxxxxx
>wrote:

 Hello coilers,


I have finally finished building my 12-30 NST powered 3.5" coil. I
managed
to get about 20" streamers on the first run. I think I can get more but I need to adjust the gap a bit. This is the first time I have used a Quick type gap. I like it's performance but it is a real pain to adjust. I am 
considering adding another easily adjustable gap in series with it.
During the run the coil didn't seem to be as loud as it should have been 
and my safety gap didn't fire once in a 60 second run. I have it set to
fire
just beyond the bare NST voltage. On every other coil I've built the
safety
gap would fire every few seconds. I'm wondering if the MOVs in my terry
filter might be clipping the the waves....Maybe thats what it's suppose
to
do.lol The output from the filter seems kind of weak to me though. I am using 18 Panasonic ERZ-V14D182 (digi-key# P7227-ND) I have two more I can 
add if needed?? Anyone have any thoughts??
Anyway, if anyone is interested I have some photos. I only got one spark 
photo before the camera battery died though.

http://s241.photobucket.com/albums/ff282/steve-vance/12-30%20Tesla%20Coil/

Steve
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