Re: [TCML] Subject: Overheated Secondary

[resonance@xxxxxxxxxxxx]

NEVER USE GAS --- PERIOD!

Big mistake.

Dr. Resonance

> Hi, well i went and got a gallon of paint thinner over 6 dollars a gallon
> so
> gasoline is cheap compared to mineral spirits... i am used to paying $2.50
> for a gallon..cul brian f.
>
>
>       www.genapro.com
> ----- Original Message -----
> From: "mark olson" <kc5gym@xxxxxxx>
> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
> Sent: Friday, January 04, 2008 10:41 PM
> Subject: Re: [TCML] Subject: Overheated Secondary
>
>
>> At 11:35 PM 1/3/08 -0800, you wrote:
>> Thanks again Bart,
>>
>> I will begin repairs tomorrow (Saturday). Surely I will post the results
> of
>> this venture.  Most of the tar is gone,
>> but even with gasoline I am not sure that it is possible to get all of
>> the
>> residue out.  I have been a mechanic
>> of one kind or another for most of 50 years, so gasoline is no strange
>> solvent for me, but it is rather expensive.
>>
>> later later,
>>
>> Marko
>>
>>
>> >Hi Marko,
>> >
>> >Inner windings are connected to the core (which is center tap
>> >configuration). Each secondary puts out about 6kVrms in your tranny.
>> The
>> >outer portion of the secondary winding is the high voltage end. This is
>> >the area which usually shorts and your tranny appears to be no
>> exception.
>> >Typically a 2 or 3 layer removal will solve the problem. Some damage
>> >occurs just in the depotting process itself from mechanical stress of
>> >removing the tar. But, after a few layers of unwinding the damaged area
> of
>> >the effected secondary, it's good as new again.
>> >
>> >I like to use new GTO cable on the hv outer secondary windings (which
>> the
>> >tranny originally used). It's good for 15kV insulation and perfect for
> NST
>> >rebuilds. I bought like 100 feet of this stuff a year ago and it's come
> in
>> >real handy (not all that expensive either). You may have found some
> gasket
>> >or cardboard material in the potting compound. Insert something similar
>> >when you repot the tranny. Allow the cardboard to keep the GTO cable
>> out
>> >of harms way (mechanically and electrically meaning more space away
>> from
>
>> >core and case is good).
>> >
>> >Removing 1/2 the shunts will put your transformer into major power
>> mode.
>> >The tranny will push a lot of current to the cap bank. It's not linear
> (if
>> >you remove about 1/2 the shunts your current may go up x3). However,
>> >that's what I did on my 12/60 and achieved about 200mA (big jump in
>> >current). My shunts where divided into two sets. Yours looks a bit
>> >different, but regardless, remove 1/3 to 1/2 of the shunts to boost the
>> >current. The difference is night and day.
>> >
>> >Something I did was to remove several secondary layers to reduce the
>> >output voltage. When I removed 1/2 the shunts, I got a big current
>> boost
>> >and reduced the voltage to a manageable level. Don't remove more than
>> say
>> >15 layers however. That will reduce your voltage down to about
>> 10.5kVrms
>> >and it's nice to keep the output voltage near the original value as
>> much
>> >as possible. However, if you find yourself unwinding more than you
>> >actually wanted to, don't worry about it too much. Simply adjust the
>> gap
>> >for the new lower arc voltage. It will do fine and due to the current
>> >increase, much better than previously realized.
>> >
>> >Try the tranny dry during shunt reduction. If you like it, pot it with
>> >your flavor of potting compound (wax, oil, whatever). Use trial and
>> error
>> >with the shunts. If it seems like a bit much, add a few more shunt
>> slabs
>> >in there until you find what your coils happy with. But definitely,
>> while
>> >you have it apart, now is the time to beef it up by removing 1/3 to 1/2
> of
>> >the shunts. That's exactly what I would do.
>> >
>> >Take care,
>> >Bart
>> >
>> >>Thanks Bart,
>> >>
>> >>My photos are here:  http://members.cox.net/kc5gym/
>> >>
>> >>I have a question or two, maybe a million.
>> >>There is a picture of the shunt in my hand. I should remove 1/2 of
> these?
>> >>
>> >>I was not able to preserve the original "angel hair" wire terminations
> on
>> >>the secondaries.  Are the inner windings
>> >>connected to center tap or are they the hv ends?  I suspect the outer
>> >>ends are the outputs.
>> >>
>> >>Thanks
>> >>Marko
>> >
>> >_______________________________________________
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>> >
>> >
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> 12:05 PM
>>
>>
>
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Dr. Resonance

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