Bad post, sorry.
Have any of you wound bifilar coils? What is the difference in performance?
Sent from my Galaxy S®III
-------- Original message --------
From: tesla-request@xxxxxxxxxx
Date:03/19/2014 2:00 PM (GMT-05:00)
To: tesla@xxxxxxxxxx
Subject: Tesla Digest, Vol 77, Issue 19
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Today's Topics:
1. Re: I think I fixed it ;^) (Scott Bogard)
2. Re: I think I fixed it ;^) (Steve Ward)
3. Re: Capacitors (Tyler Burns)
4. Re: Capacitors (Jim Lux)
----------------------------------------------------------------------
Message: 1
Date: Tue, 18 Mar 2014 10:30:11 -0400
From: Scott Bogard <sdbogard@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: Re: [TCML] I think I fixed it ;^)
Message-ID:
<CACCAFV0yg_hTSgFiysvQm2qtGonafV96D5-_7Et3e_oSgawC6A@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset=ISO-8859-1
David,
Glad you got that sorted out, it does make me wonder though, how do
folks manage to build DRSSTCs and not have all the components explode...
I'm wondering if you could leave hte brick grounded if it was in a cage or
something, though I suspect not. At any rate, good job!
Scott Bogard.
On Tue, Mar 18, 2014 at 7:41 AM, David Rieben <drieben@xxxxxxx> wrote:
> Hi Adam,
>
> Yes, I am still using the same treadmill motor. Like I had mentioned
> previously, I had changed up the 120 volt wiring for the RSG motor
> strictly for an asthetic upgrade, but had left the electrical layot iden-
> tical, EXCEPT, I had started grounding the exterior metal case of
> the FWB brick. That was obviously a big NO-NO, as the FWB
> was promptly destroyed as a dead short within seconds of engaging
> the spark show from my coil. And since I was trying to fire it for
> a small audience of middle school children, I tried to "push" it even
> though I could quickly tell something was seriously wrong, when it
> initially happened. As a matter of fact, I ended up actually catching
> the 10 amp, 120 volt rated RSG control variac on fire! Thankfully,
> those 35 or 50 amp, 1 kV rated FWBs bricks are relatively cheap
> and readily available on eBay, because I ended up smoking a couple
> of more before finally figuring out the grounding issue. Also, thankful-
> ly, I had a spare 10 amp, 120/140 volt rated variac that was just
> about identical to the flamed one, including an identical mounting foot
> print, so no messing up my control panel face with additional holes :^)
>
> Lesson learned: NEVER make any modifications to your known
> working coil and then try to display it in action for civilian observers
> without giving her a SPARKING "test drive", as the FWB and mo-
> tor would run fine all day with NO sparks after my modification!
>
> David
>
> From: Yurtle Turtle <yurtle_t@xxxxxxxxx>
> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> Sent: Tuesday, March 18, 2014 4:21 AM
> Subject: Re: [TCML] I think I fixed it ;^)
>
>
> Good to hear. Are you using the treadmill motor discussed a while back?
>
>
>
>
> ________________________________
> From: David Rieben <drieben@xxxxxxx>
> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> Sent: Monday, March 17, 2014 10:30 PM
> Subject: [TCML] I think I fixed it ;^)
>
>
> Hi all,
>
> For those of you who remember my "help please" thread, about my Green
> Monster Tesla coil suddenly seeming to have developed an appetite for the
> FWB rectifier for the ARSG motor, I think I have fixed the problem (keeping
> my fingers crossed). I tried mounting the FWB "brick" on a flat piece of
> cop-
> per for heat sinking WITHOUT grounding the external metal case of the
> brick.
> I also installed an extra corcom line filter upstream of the FWB and in-
> stalled a 20 amp button circuit breaker upstream of the RSG control
> variac, so as to not engulf it in flames in case of another FWB going
> dead short. I wheeled her out tonight and I ran her for a good minute
> or so without a hitch (it was smoking the FWB rectifiers within seconds
> before making the "corrections"). I was still a bit "gun shy" to really let
> her rock tonight but was able to determine that I had obviously cor-
> rected the rectifier eating problem. Thanks for the helpful suggestions to
> all who responded to my "plea".
>
> David Rieben
> _______________________________________________
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> Tesla@xxxxxxxxxx
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>
------------------------------
Message: 2
Date: Tue, 18 Mar 2014 18:10:21 -0700
From: Steve Ward <steve.ward@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: Re: [TCML] I think I fixed it ;^)
Message-ID:
<CAD=yrf=uHSQE_dU0dk_cX8eirL6M37ry_RtD17WC-_OdRP-upg@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset=ISO-8859-1
Scott,
Its taken years of "learning" to avoid the very same problem David is
having.
The problem is simply this, your RF ground is bouncing by many kV relative
to other power supplies or line voltage. This stresses the insulation
between diode and heatsink until it blows up.... David knows this now :-).
For DRSSTCs its common practice now to use "RF bypass" capacitors between
the power bus and "ground" so that there cannot be large transient
potential that stresses the silicon isolation. Being initially clueless
about this issue explains a lot of my IGBT grave yard
:-). So it really comes down to using pretty standard EMI suppression
techniques to avoid blowing things up around tesla coils.
Steve
On Tue, Mar 18, 2014 at 7:30 AM, Scott Bogard <sdbogard@xxxxxxxxx> wrote:
> David,
> Glad you got that sorted out, it does make me wonder though, how do
> folks manage to build DRSSTCs and not have all the components explode...
> I'm wondering if you could leave hte brick grounded if it was in a cage or
> something, though I suspect not. At any rate, good job!
>
> Scott Bogard.
>
>
------------------------------
Message: 3
Date: Tue, 18 Mar 2014 18:36:47 -0400
From: Tyler Burns <t-burns14@xxxxxxxxxxx>
To: "tesla@xxxxxxxxxx" <tesla@xxxxxxxxxx>
Subject: Re: [TCML] Capacitors
Message-ID: <COL127-W55AC141C1F09E45683076EB7C0@xxxxxxx>
Content-Type: text/plain; charset="iso-8859-1"
So I'm looking at Cornell Dubilier's 942C series and I need some more guidance. Does the VDC rating matter since these use AC? Regardless, what range voltage rating should I be looking at? Or at least what is it related to so I can do my own calculations.As far as capacitance per individual cap, I assume that depends on how many caps I want to buy, as the number of strings and number in series can create infinite combinations to reach a specific capacitance. Oh and it will also depend on my voltage as well, so it can handle the voltage.
Please correct any of this if it's wrong and answer any of these many questions if you can.
Thanks guys,Tyler
------------------------------
Message: 4
Date: Tue, 18 Mar 2014 20:31:43 -0700
From: Jim Lux <jimlux@xxxxxxxxxxxxx>
To: tesla@xxxxxxxxxx
Subject: Re: [TCML] Capacitors
Message-ID: <53290F9F.3000802@xxxxxxxxxxxxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
On 3/18/14 3:36 PM, Tyler Burns wrote:
> So I'm looking at Cornell Dubilier's 942C series and I need some more
> guidance. Does the VDC rating matter since these use AC? Regardless,
> what range voltage rating should I be looking at? Or at least what is
> it related to so I can do my own calculations.As far as capacitance
> per individual cap, I assume that depends on how many caps I want to
> buy, as the number of strings and number in series can create
> infinite combinations to reach a specific capacitance. Oh and it will
> also depend on my voltage as well, so it can handle the voltage.
> Please correct any of this if it's wrong and answer any of these many
> questions if you can. Thanks guys,Tyler
>
There's some MMC calculators out there (geekgroup, maybe)..
DC rating is important in the sense that you use that to figure out
your rating based on the peak voltage of your source. For instance, a
15kV (RMS) NST has a peak voltage around 21 kV (15*1.414).. I'd be
comfortable with running 11 2kV caps in series (22kV).. i'd even be
comfortable running 10 in series. Maybe even 9, living a bit dangerously.
There's lots of posts in the archives from more than 5 years ago about
how far you can push these babies. (you might look for "EMMC")
A more important thing for longevity is the RMS current. Overheating
will kill the capacitor.
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