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Those of us who design and build exhibits adapt "found objects" to make
our jobs easier as well as making the exhibits better and cheaper.
Sometimes it seems the most useful items are made obsolete by technical
advance. For example, there's been lament over the advent of digital
photography signaling the end of those very useful film cans.

However, as some things leave others appear that are useful. Electronic
Ballasts for fluorescent lamps are a perfect example. Advance (a leading
manufacturer of ballasts) makes a very handy 25 watt unit which I have
adapted to drive an old 1950s TV flyback transformer to run a Star
Sculpture we have. 

The specific Advance Part Number is: RCN-1P32-SC. This particular
ballast is designed to run a single two pin lamp and puts out about 25
watts of power at 42 KHz. It has an open circuit voltage of 600. Maximum
lamp current should be limited to 180 to 200 MA. Nominal lamp current is
180 MA, nominal lamp operating voltage is 137. 

I have found it prudent to drive the load in series with an 18 watt lamp
or 1000 ohm resister. Doing this will protect the ballast and limit the
output current. If you have an RF milli-ammeter, it's a great idea to
monitor what's going on too. I would suggest that you limit your
experimenting to those ballasts that are designed for single two-pin
lamps as it can get tricky faking the filaments used in four pin lamps
or balancing the loads represented by the other lamps with ballasts
designed to run two or more lamps.

So if you find that you need AC with this power and frequency here's a
really inexpensive way to get it. I bet these would drive Tesla Coil
variants nicely too. The beauty is that if it does die in service you
can buy a replacement at any good electrical supply house.

Happy experimenting!

John Bowditch
Exhibits Director
Ann Arbor Hands-On Museum

Tel:	(734) 995-5439
FAX:	(734) 995-1188

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