Re: tested my coil at neon shop!

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

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Neonglo-at-aol-dot-com>

In a message dated 12/21/01 6:17:39 PM Central Standard Time, 
tesla-at-pupman-dot-com writes:

<< what exactly are bombarders ?  >>

Essentially, it is a large non-current-limited transformer used in the 
production of neon tubing. They are used to ionize low pressure air with a 
great deal of current in a new neon tube in order to heat the glass and 
electrodes. Once the glass reaches about 500 degrees F. and the electrodes 
are glowing bright orange, the remaining air and other impurities are 
exhausted with the vacuum pump before the inert gas is admitted.

Most bombarders are either dry or asphalt filled. They are very similar to a 
pole pig except they are not as rugged for TC use. This is because they 
normally see only a purely resistive load during their intended use, and are 
not built as rugged as an oil filled pole pig.  Sometimes pole pigs are used 
as bombarders, but a bombarder is not rugged enough to be used as a pole pig 
because it is not intended for continuos duty. Bombarders are smaller and 
lighter because of this. 

Bombarders are controlled by either a sliding core choke, a tapped reactor, 
or a saturable reactor. Typical ratings for bombarders are from 7.5kVA, to 
22.5kVA, and are usually in the 20kV to 24kV range. The older ones were 
usually centertapped on the secondary, but most new ones have a floating 
secondary to prevent flashback to the pumping manifold.

A bombarder would make a great TC power supply, but a good kickback 
protection circuit would be a very good idea if you decide to use one. They 
will not withstand the impulse (BIL rating) that a pole pig will. Also some 
means of ballasting will be required. On top of that, they are usually more 
expensive than a pole pig of equal size. But if you find one for cheap, it 
should work just fine for TC use. 

Tony 
----------------
Tony Greer
Special Effects Neon
Lubbock, Texas
"Flowing Glass and Glowing Gas"