Re: Ballast bulk buy / Bombarder Chokes

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Steve White by way of Terry Fritz <twftesla-at-qwest-dot-net>" <slwhite-at-zeus.ia-dot-net>

I would like to know the dimensions of your 5 KVA unit. I have been
wrestling with how to build a reliable ballast at this power level. I would
like to know the following.

1. Dimensions of core
2. Bobbin dimensions
3. Number of turns

What sort of duty cycle do you get with your ballast?

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, August 11, 2001 5:11 PM
Subject: Re: Ballast bulk buy / Bombarder Chokes


> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<Neonglo-at-aol-dot-com>
>
> In a message dated 8/9/01 9:47:17 AM Central Daylight Time,
tesla-at-pupman-dot-com
> writes:
>
> << Hi All
>
>  I have a lot of x-ray transformer laminations of various sizes. In
>  particular I have enough laminations of size 22.75"L x 4"W to a form a
bar
>  core of size 22.75"L x 4"W x 4"H. I am thinking about making a bobbin
that
>  the core could slide through, and then wind the bobbin with very heavy
wire.
>  Does anyone think that this is a worthwhile approach to build a variable
>  ballast? The big problems for me would be pulling heavy copper wire
tightly
>  around the bobbin, and constructing a mechanism for sliding the core.
>
>  Godfrey Loudner  >>
>
> Hi Godfrey, All,
>
> What you are describing here sounds like the way some neon bombarder
chokes
> are made, which work really well on pole pigs too. They are basically what
> you describe, with a handle attached to the end of the laminations, and
> usually a mechanism to allow the core to be pulled out, but which will not
> let it be pulled back in. (This type of sliding choke is also a very
strong
> solenoid!)
>
> While you can buy ready made chokes in sizes from 5 to 15 kVA, they are
very
> pricey for what they are. They will cost in excess of $500, which is a lot
> for a laminated core and a coil of wire. (Here is a page from Daco Neon's
> catalog with a very fuzzy picture of a sliding choke and bombarder.
> http://www.daconeon-dot-com/page5.html ) I don't see why a very successful
choke
> could not be made, especially if you already have the core material. Use a
> stranded THHN wire with enough capacity for the current you will be
running,
> and build a very sturdy bobbin the length of the core. You will need some
way
> of holding the core in position while it is energized, because it will
have a
> very strong pull! Different length blocks of wood can be placed between
the
> bobbin and a bracket on the end of the core.
>
> I have both a 5 kVA and a 12.5 kVA sliding choke at the shop which I can
get
> some of the important dimensions from if anyone is interested. If a
suitable
> core can be found, the rest should be simple and straightforward to build.
>
> Tony
>
> ------------------
> Tony Greer
> Special Effects Neon
> Lubbock, Texas
> "Flowing Glass and Glowing Gas"
>        ~~~SINCE 1980~~~
>
> New Geissler Gallery: http://hometown.aol-dot-com/thepacratz/xfmrs.html
> eBay Page: http://members.ebay-dot-com/aboutme/thepacratz-at-aol-dot-com/
>
>
>
>