Hi Phil,
Although I can't comment upon your preference for varying the input inductance, via the ballast, instead of varying the the input voltage, via the variac, as I have very limited experience with this avenue of input power management, I have personally had very satisfying results with a "fixed" ballast, while varying the input voltage, via the variac. It sounds like a suitable saturable reactor or slide choke (or just the different amperage settings of a "tombstone" or "buzz box" stick welder) is what your proposed method of power management calls for. Maybe your method does offer a broader range of power control, but I am actually quite pleased with the power management afforded with my fixed ballast inductance/infinite voltage adjustment for fine power management through the input variac. And once the ballast is completed, it is a simpler setup as well. Then there are some who employ a combination of BOTH of these means of power management in their systems. Just my $.02 ;-)
David
Sent from my iPhone
> On Aug 6, 2015, at 7:46 AM, Phil <pip@xxxxxxxxxxx> wrote:
>
> Miles,
> By using the input variac as the control you are only "indirectly"
> controlling the power - by altering the input voltage to the pig. A better
> way, assuming you run 100% at the moment when it suits you, is to vary the
> power directly by running with full variac but varying the ballast value
> instead.
>
> With any external ballast there is always going to be a favoured mH value
> (sweet spot) that combines with the MMC value to give resonant charging, and
> by altering the ballast setting instead, you can hopefully vary it to find
> the best performance point. (Assuming your ballast covers the correct range)
>
> See Richie's webpage at http://www.richieburnett.co.uk/async.html
>
> He posted on TCML about it as well in June 2001, but that post has dead
> graph links that the post references to, but a complete verbatim copy with
> his original graphs also included can be found here:
>
> http://www.hvtesla.com/richie.html
>
> I've used the system for years
>
>
> Regards
> Phil Tuck
>
> www.hvtesla.com
>
>
>
>
>
>
> -----Original Message-----
> From: Tesla [mailto:tesla-bounces@xxxxxxxxxx] On Behalf Of Miles Mauldin
> Sent: 06 August 2015 02:33
> To: Tesla Coil Mailing List
> Subject: Re: [TCML] Variable Ballast
>
> I picked up a Lincoln AC 225-S Variable Voltage ARC Welder. Big heavy
> clunker and runs in 220 V.
>
> Questions:
> This unit has a selection of 11 settings, is this the type of unit most of
> you use?
> Is there a formula other way to know the amperage of each setting, or do I
> need to just start on the lowest setting and measure?
> Basically I use the welder on a fixed setting most of all of the time and
> vary the coil power with a variac, correct?
>
> Best!
> Miles
> Sent from iCloud on a little Device with a tiny keyboard...
>
>> On Aug 3, 2015, at 10:52 AM, Buds tape mail <bud@xxxxxxxxxxxx> wrote:
>>
>> Hi all,
>>
>> The toroid is 14.5 inches on the ring diameter and the main diameter is
> 56" dia. The secondary......with the toroid.....and with a 10' leader off
> the toroid all resonate at 53 khz. Tested for this last night! The toroid
> was built using foam panels 3.5" thick. Very similar construction as
> spelled out in HVTESLA.COM . I put 1/4" ply on the top and bottom
> sides of the inner toroid. Filled the gaps with foam and spun on an axle of
> 2" PVC right thru the center. This allowed me to spin the whole unit
> between two picnic tables with my 1/2" drill using a variac . I smoothed
> the foam ring now rough as all get out with a 90 deg. grinder with a very
> aggressive sanding disk. The foam was all over me! Not a project for
> indoors as the foam is now all over the yard and blowing everywhere. Wife
> is not happy......go figure! The a layer of spackling was applied and later
> sanded to just smooth the rough foam out. Then primed with stain blocking
> primer. Then a layer of fib
> er glass was applied all over.....this was to add surface strength as the
> foam is very soft and dents easily. Then another layer of spackling and
> then sanded smooth. This is where doing body work came in handy! Then
> primed again and then a layer of aluminum tape was added for the final
> finish. This thing looks like it was turned on a lathe!......well it was
> sort of! The 1/4" ply gives me the base I needed to support the toroid and
> to mount the upper terminal to.
>>
>> The cool thing is the toroid is not real heavy. 50-60 lbs.
>>
>> The entire unit was assembled yesterday and stands around 10' tall. Yes I
> have plenty of room to get it in and out of the barn.
>>
>> Does anyone know the address for the Teslathon at Roger's in Chillicothe
> this coming weekend? Got the invite from Roger but not the address. Is
> anyone else going?
>>
>> Bud Mohrman
>>
>> -----Original Message----- From: Phil
>> Sent: Saturday, August 01, 2015 4:16 AM
>> To: 'Tesla Coil Mailing List'
>> Subject: Re: [TCML] Variable Ballast
>>
>> Bud,
>> This sounds like a very interesting coil being created! What size minor
> dia'
>> toroid are you using and is it SRSG or ARSG, 120/240 bps?
>> Don't forget to post a YouTube link
>>
>>
>> Regards
>> Phil Tuck
>>
>> www.hvtesla.com
>>
>>
>>
>> -----Original Message-----
>> From: Tesla [mailto:tesla-bounces@xxxxxxxxxx] On Behalf Of Buds tape mail
>> Sent: 31 July 2015 13:22
>> To: Tesla Coil Mailing List
>> Subject: Re: [TCML] Variable Ballast
>>
>> Hi Phil and others, I have been reading thru your web site and Richie's
>> very thoroughly. I have built a 12" X 51" secondary #18 wire and have
>> finished a 56" toroid and will have this thing ready to go very soon. I
>> have a rotary spark gap (copy of Ed's in Rochester) and a 14kv pole pig.
> I
>> have been reading extensively about primary inductive ballast. I do have
>> two 225 amp buzz boxes I could use in parallel as ballast like others have
>> done. I understand the principle series on the primary side limiting the
>> power to the pig.
>>
>> I saw how and why you wound your own ballast. My question is
>> this........can we just use a very large welding transformer........say
> 400
>> amp unit as the ballast while shorting the secondary or should we just
> bite
>> the bullet and wind a huge ballast from an older transformer with a huge
>> iron core? I have my own machine shop.......... www.tape-inc.com
>> ..........and can do almost anything once I know what it is I need to do.
> I
>>
>> think most of us do not know the how and whys of ballast design.....you
> know
>>
>> the core size min/max and wire size min/max for a pig of this size.
>>
>> Bud Mohrman
>>
>> -----Original Message----- From: Phil
>> Sent: Friday, July 31, 2015 5:16 AM
>> To: 'Yurtle Turtle' ; 'Tesla Coil Mailing List'
>> Subject: Re: [TCML] Variable Ballast
>>
>> Jon,
>> The modern cheap import ones you see knocking about are generally not up
> to
>> the job for a pole pig, without getting pretty hot during use. I melted
> and
>> shorted the windings of one a while back while running @ 10.5kv / 400mA -
>> (hardly pig output) simply because I left it running for several minutes
>> (they normally have a thermal cutout to disconnect the mains input during
>> normal use)
>> Their duty cycle is very low sometimes, especially as Yurtle mentions, if
>> Alu' conductor is used; also the resulting voltage drop from lossy
> windings
>> gets multiplied up by the pig, so you could potentially be losing 0.5kv at
>> the worst case.
>> Winding your own ballast is a better option.
>>
>>
>> Regards
>> Phil Tuck
>>
>> www.hvtesla.com
>>
>>
>>
>> -----Original Message-----
>> From: Tesla [mailto:tesla-bounces@xxxxxxxxxx] On Behalf Of Yurtle Turtle
> via
>>
>> Tesla
>> Sent: 30 July 2015 20:52
>> To: GENE GARRAGE; Tesla Coil Mailing List; Tesla Coil Mailing List
>> Subject: Re: [TCML] Variable Ballast
>>
>> I got a 225 amp Lincoln welder at a garage sale.It was old enough to have
>> copper windings. I chose to short the welding leads internally, and
>> eliminate the cables.
>>
>> From: GENE GARRAGE via Tesla <tesla@xxxxxxxxxx>
>> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
>> Sent: Wednesday, July 29, 2015 6:53 PM
>> Subject: Re: [TCML] Variable Ballast
>>
>>
>> From: Jon Danniken <danniken@xxxxxxxxxxx>
>> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
>> Sent: Thursday, July 2, 2015 2:28 PM
>> Subject: Re: [TCML] Variable Ballast
>>
>>> On 07/01/2015 11:14 AM, Miles Mauldin wrote:
>>> Do I need to find an old welder, or will an inexpensive new one work
>>> just as well. Read many posts about shorting the secondary and using
>>> the primary in line with a pole pig. Thoughts, ideas or suggestions
>>> all wanted for a variable ballast.
>>
>> You can get an old 220V arc welder for cheap on craigslist if you are
>> patient, less cheap if you are not patient. As a bonus, you also get a
>> welder.
>>
>> Jon
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