Page:Popular Science Monthly Volume 92.djvu/329

 Popular Science Monthly

��A New Condenser to Protect Wireless Generators

IF a layman were shown about the wireless cabin on board a battleship, without a doubt he would consider the rack of condensers about the least im- portant part of the equipment. The experienced amateur knows better. He knows that should the condensers break down, the entire sending machinery is likely to collapse. Even leaking con- densers may cut down the efficiency of the station so that it would be difficult, if not impossible, to comunicate over a long distance. Think what this would mean if a warship were on a scouting cruise and discovered something im- portant!

Though it is not generally known, an accident such as this was always threaten- ing to isolate the ships of a fleet, not very much more than a year ago. Most ships were using glass Ley den jars or glass plate condensers at this time. The im-

���A condenser built of several units, which are insulated from one another as well as each of the plates within each unit

mense voltages across the high-tension transformer that the jars had to stand, continually broke them down under the

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prolonged strains, and only protective condensers across the wireless generator, saved it from utter destruction. Moreover,

���The same method is used in this condenser, although it is of very different construction

brush discharges invariably took place through the glass of the condensers. These discharges increased in intensity as the glass weakened with use. The dis- charges contaminated the air with ozone, which made it hard for the operators to work; to say nothing about the decrease in the sending power that they produced.

The Navy Department has now elimi- nated the glass condenser, and thus has done away with its disadvantages. A mica condenser, the development of William and Philip Dubilier, of New York city, is now used exclusively. This condenser is made up of a number of units connected together in series. The result is that the full potential across the transformer is divided a good number of times before it acts across any of the units. The voltage that does result across a single condenser is correspond- ingly sm.all; too small, in fact, to set up any detrimental brush discharge action. Such sets of condensers ought to be highly efficient, and, theoretically, ought to last a life time.

Each of the units is built up of al- ternate sheets of copper foil and mica, the copper foil being connected in mul- tiple as in ordinary mica condensers. Though the probability of a breakdown of the mica has been made exceedingly small, the chances of such a breakdown injuring the station has been made

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