Letters

“Regarding your reply in Volume 6, #3, to the question as why capacitors in series keep breaking down. The reason may be that the total voltage rating of the series connection was not high enough to withstand the applied AC potential. The voltage rating of a capacitor should be at least double the applied AC voltage. Also, only glass or mica dielectric capacitors should be used in RF power circuits. The so-called oil capacitors are actually constructed of paper or plastic film dielectrics with the oil only serving as an insulating filler. Such capacitors are not designed to withstand high frequency currents which cause the dielectric material to become hot (diathermy action) with eventual breakdown. Such capacitors may function for a while if the voltage rating is high enough and use is intermittent but are definitely out of place in high powered tank circuits. Furthermore, many oil capacitors contain toxic PCB's which could be released if the capacitor ruptured.” (Thomas J. Butkus)

“They (TCBA NEWS) are a refreshing change from the usual run of electronics publications for those of us who can envision potentials greater than 15 volts. As always, my congratulations on your fine publication. I am proud to be a member of TCBA.” (Tom Hamilton)

“The project in Volume 6, #4, 'Tesla Coils with Ford Spark Coil,' brought back memories. It was that article that got me started in all this when in grade school.” (Leland I. Anderson) Editor's note: Hugo Gernsback would be delighted to know that one of the boys who built that coil went on to become a leading authority on N. Tesla.

“The Wardenclyffe-like structure shown on page 3 of Volume 6, #2, is not a grain storage bin but a saw mill's defunct incinerator. Many of these are still standing in northern California lumbering areas and are now outlawed by air pollution ordinances. They were used to burn slash, etc. I did a double-take, too, when I first saw one.” (George Trinkaus)

“I would like to commend you for the fine series of publications of TCBA NEWS. I have completely enjoyed each and every issue and have devoured them from cover-to-cover, page-by-page, and article-by-article.” (W.H. Richards)

“The article on 'Resurrecting Old Transformers' was not quite clear as to how the increased output was achieved. Normally, a transformer of this type will produce more power if the shunts are removed. The diagram shows an arrow with the instructions to 'remove these laminations.' The arrow, however, was not pointing to the shunts.

“I would also like to pass on an old trick that was learned from the late Ken Strickfaden. A transformer will give twice the rated current and one-half the rated voltage if one of the secondaries is removed from the core and reversed before being replaced. The secondaries are then hooked in parallel. This hookup following the coil reversal also allows the secondary to have one end grounded.” (Dick Aurandt)

Editor's note: In reference to the article mentioned above, some experimentation might be in order when it comes to the choice of solvents for softening the insulation in transformers. One old-timer told me that they used to dip the ends of wire in solvents to aid in the removal of insulation covering the conductor. This made it easier to scrape away the insulation for making connections. Any solvent that softens the wire insulation is sure to have an effect on the life of the transformer.

Another tip that has come down the vine is to place your transformer in a freezer until the insulation has had time to completely harden. After that, the insulation can be easily chipped away with a screwdriver and hammer. Of course, care must be taken not to damage the windings.

While I have your attention, I would like to report that many members responded to my invitation to comment on the price increase and possible changes in making TCBA NEWS less expensive. All* incoming letters favored keeping the NEWS as is. One member wished it was longer (more pages). Others were willing to pay twice as much. One writer stated it was worth $30 and sent in a check for that amount. Another reader declared TCBA NEWS to be worth $40 (hmmm?). Some members ignored the price increase and sent in the usual $16. Incidentally, any overpayment is credited to that person's account and carried over into the next year's subscription.

There were at least two members who offered to sponsor subscriptions for anyone unable to pay. Golly, can you find nicer people? In this regard, you might be interested to know that TCBA has honored requests for deferred payment, one-half payment, and no payment at all for those who have made such requests due to economic hardship. In more than one case, I have given up to a full year subscription at no cost. After that, the nonpaying member was kept on the mailing list if he became a paid member (even though the back issues remained unpaid). Of course, there are limitations as to how many members TCBA can carry in this way.

* After writing this, a letter arrived questioning the value of the “Tesla Coils Resurrected” column. Another writer suggested we drop the use of photographs.