RE: [TCML] Welder core as Ballast

["Jim Mora" <wavetuner@xxxxxxxxx>]

Hi Phil,
I'm curious. What are the core sizes and wire size of your 3p inductor?
Jim Mora

-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of Phil Tuck (hvtesla)
Sent: Saturday, October 10, 2009 6:05 AM
To: 'Tesla Coil Mailing List'
Subject: RE: [TCML] Welder core as Ballast

Hello Scott et al
Thanks for the info but unfortunately, or fortunately which ever wau you
look at it, I will be using something else instead. I have been offered a 3
phase 11kva inductor which will be much better suited. The welder was
pushing a bit on the core and window size anyway.

>> Expect about 3 amps current of each square inch of center core leg 
measure...  
That agrees with what I found with my homemade transformer. That was 8 sq
inches, and saturated around 22/24 amps

Regards
Phil


-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of BunnyKiller
Sent: Friday, October 09, 2009 11:11 AM
To: Tesla Coil Mailing List
Subject: Re: [TCML] Welder core as Ballast

Hey Phil...

normally the secondary is shorted to make the transformer more effective 
for ballasting.
When the secondary is shorted, the "load" is reflected back to the 
primary to create " more current control" when used as a ballast.
If the secondary is open, the current control seems to be more so of 
core magnitizing current flow leaving you with very little current 
capacity or core saturation issues depending on core design.

Since the primary needs rewinding, keep the design as it is, utilizing 
the slide. Short out the secondary, and rewire the primary with wire 
thick enough to handle the current requirements of the load you intend 
to draw through the hi volt transformer.

If the core of the welder is able to be separated, you shouldnt have too 
tough of a time rewinding....  if it isnt, then rewinding is going to 
take some time
 be patient, dont kink the wire....

One last thought....  you can rewind the core as a standard inductor IF 
the center leg is of substantial size and the core is an EI configuration.
Expect about 3 amps current of each square inch of center core leg 
measure...  example, center core leg is 3X4 ( 12 sqr inch) this gives 
you approximately 36 amps of current control. Wire to consider would be 
solid copper core at about #8 with THHN insulator jacket.

Also, if you leave the secondary of the welder in place, you need to pay 
attention to the " duty cycle" listed on the welder. The duty cycle is a 
Time On/Time Off cycle depending on current flow through the secondary. 
If the duty cycle is exceeded, the windings of the welder will go into 
melt down and let the smoke out ;)

Scot D


Phil Tuck (hvtesla) wrote:

>Hello.
>
>When using a welder for ballast it is normal to short the secondary leads
as
>this increases the inductance of the primary considerably, but why does it
>increase it?
>
>The reason I'm asking is that I have an old 160 amp welding transformer,
the
>sort with the secondary one side and the primary on the other with a slide
>in between. What is the best way to rewind this as a ballast coil with this
>setup. (The existing primary needs rewinding anyway)
>
> 
>
>1) Wind a new primary coil to achieve a suitable inductance and leave the
>existing secondary in place and short circuit it.
>
> 
>
>2) Wind a new primary and a new secondary and connect them in series. 
>
> 
>
>Bearing in mind I still wish to use the slide to vary the inductance I'm
not
>too sure if the second method would be very effective.
>
> 
>
>Phil
>
>_______________________________________________
>Tesla mailing list
>Tesla@xxxxxxxxxx
>http://www.pupman.com/mailman/listinfo/tesla
>
>  
>


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