[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: mysterious coil failure (fwd)
---------- Forwarded message ----------
Date: Tue, 30 Oct 2007 20:10:36 -0800
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: mysterious coil failure (fwd)
Hi Gary, All,
I meant to say "concurrent" readings (happening at the same time), not
concentric. Sorry about that. Looks like I need to fix that. The point
is to view both V and I at the same time. The values can bob up and
down, so using a single meter is "not" very accurate. Accuracy with this
method requires 2 meters side by side. Using a hairdryer for the ballast
is my recommendation. It's been the best load that has the least
fluctuation in my experience. Just let the hairdryer heat up and the air
does a great job to stabilize the load. This method works great and was
first described to me by Terry Fritz. I've done it with and without the
RC network (it's not needed).
Take care,
Bart
Tesla list wrote:
> ---------- Forwarded message ----------
> Date: Mon, 29 Oct 2007 13:04:46 +0000
> From: "Lau, Gary" <Gary.Lau@xxxxxx>
> To: 'Tesla list' <tesla@xxxxxxxxxx>
> Subject: RE: mysterious coil failure (fwd)
>
> One doesn't need a signal generator or scope of any kind to measure
> coupling. You need only know the primary and secondary inductance, and
> perform the measurement described at
> http://www.classictesla.com/download/M_and_k_Measurement.gif
>
> I've not found it necessary to include the RC network across the
> secondary. The wording is confusing with "Take concentric readings from
> meters." I think what was meant is to take both primary current and
> secondary voltage measurements at the same time on separate meters.
>
> Regards, Gary Lau
> MA, USA
>
>
>> From: resonance <resonance@xxxxxxxxxxxx>
>> To: Tesla list <tesla@xxxxxxxxxx>
>> Subject: Re: mysterious coil failure (fwd)
>>
>>
>>
>> You need to check your coeff. of coupling and usually keep it below 0.12 for
>> most classic spark gap coils. Some of my coils run best with greatest spark
>> output at .08 to 0.1 range. A local Univ. or tech college with a storage
>> scope and sig gen can help you do this. The equations and procedures are in
>> the Tesla List Archives.
>>
>> If your coeff. of coupling is producing a "double hump" then your coupling
>> is too tight, energy is being wasted, and your coil will hit HV peaks at two
>> points --- sometimes not at the end of the sec.
>>
>> This produces tracking and eventually destruction of the coil.
>>
>> Also, be sure to always sand both interior and exterior of any coilform
>> prior to winding. Also use some small acrylic baffles approx 6-8 inches
>> down from each end in the sec. Silicone into place with GE Silicone II ---
>> available at most hardware stores.
>>
>> Dolph's AC-43 has much greater anti-tracking properties than polyurethane,
>> and it's price is reasonable if you consider the amount of repair time that
>> is required when a coil fails.
>>
>> Dr. Resonance
>>
>> Resonance Research Corp.
>> www.resonanceresearch.com
>>
>>
>> ----- Original Message -----
>> From: "Tesla list" <tesla@xxxxxxxxxx>
>> To: <tesla@xxxxxxxxxx>
>> Sent: Sunday, October 28, 2007 8:03 PM
>> Subject: RE: mysterious coil failure (fwd)
>>
>>
>>
>> ---------- Forwarded message ----------
>> Date: Sun, 28 Oct 2007 19:50:56 -0400
>> From: Scott Bogard <teslas-intern@xxxxxxxxxxx>
>> To: Tesla list <tesla@xxxxxxxxxx>
>> Subject: RE: mysterious coil failure (fwd)
>>
>>
>> Thanks guys,
>> I don't think it was a shorted turn, there is no carbon on the inside
>> but there is a tiny black spot on the outside (I don't use end caps on my
>> coils, is this bad?). I attach my RF ground by a copper strap, soldered
>> onto the end of the bottom turn, I think it arced from the sharp edge of
>> the strap to the wire above it (turn 2). This occurred underneath of the
>> several layers of electrical tape coated with polyurethane insulation on
>> the bottom. One other detail I forgot to mention, I set the coupling as
>> high as I could get it that night to make up for decreased performance
>> from wind and humidity, so that may have contributed. I'll sand her down
>> and rewind the bottom and see if it works again, thanks guys.
>>
>> Scott Bogard.
>>
>>
>>> Date: Sun, 28 Oct 2007 11:07:40 -0700
>>> From: tesla@xxxxxxxxxx
>>> To: tesla@xxxxxxxxxx
>>> Subject: Re: mysterious coil failure (fwd)
>>>
>>>
>>> ---------- Forwarded message ----------
>>> Date: Sun, 28 Oct 2007 11:01:32 -0800
>>> From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
>>> To: Tesla list <tesla@xxxxxxxxxx>
>>> Subject: Re: mysterious coil failure (fwd)
>>>
>>> Hi Scott,
>>>
>>> Yes, the glowing spot is either a shorted turn or carbon track. It may
>>> be a shorted turn and easy to fix if right on the bottom, and "if" it is
>>> like the very bottom turn, it's probably too much power for too long a
>>> period. I've had this happen on my 4" coil even with low coupling. If
>>> enough power is provided, it can cause extensive heating a greatest
>>> heating on the bottom of the secondary (highest current). If you were to
>>> continue running it, a nice little fire will begin. If it's a shorted
>>> turn, you'll have a nice black carbon ring around the entire turn. Real
>>> easy to fix obviously.
>>>
>>> Take care,
>>> Bart
>>>
>>> Tesla list wrote:
>>>
>>>> ---------- Forwarded message ----------
>>>> Date: Sat, 27 Oct 2007 22:10:06 -0400
>>>> From: Scott Bogard <teslas-intern@xxxxxxxxxxx>
>>>> To: tesla@xxxxxxxxxx
>>>> Subject: mysterious coil failure
>>>>
>>>>
>>>> Hey guys,
>>>> I was running my 6-in MOT coil tonight for my little cousins, and
>>>> it
>>>> died and I cannot figure out what is wrong. The spark gap fires fine, I
>>>> did not adjust anything, it just died between runs, and won't arc except
>>>> to a grounded rod (it acts like it is badly out of tune, but like I
>>>> said,
>>>> I adjusted nothing). The only thing different I notice, is that there
>>>> was
>>>> very high humidity, and I could see a tiny spark at the base of the
>>>> secondary. It isn't arcing to anything, it is just a glowing spot, that
>>>> melted through the electrical tape insulation. I'm stumped, I guess
>>>> I'll
>>>> tear the insulation off of the bottom of the sec' coil and see if
>>>> anything
>>>> is amiss, but I've never had a failure like this before. The only other
>>>> possibility is that somehow my ballast malfunctioned, but I don't think
>>>> so.
>>>>
>>>> Scott Bogard.
>>>>
>>>>
>>>>
>> _________________________________________________________________
>>
>>>> Help yourself to FREE treats served up daily at the Messenger Caf?. Stop
>>>> by today.
>>>>
>>>>
>> http://www.cafemessenger.com/info/info_sweetstuff2.html?ocid=TXT_TAGLM_Oct
>> WLtagline
>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>> _________________________________________________________________
>> Windows Live Hotmail and Microsoft Office Outlook - together at last. Get it
>> now.
>> http://office.microsoft.com/en-
>> us/outlook/HA102225181033.aspx?pid=CL100626971033
>>
>>
>>
>>
>>
>>
>
>
>
>
>
>
>