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arc leaps across the safety gap at the base of WLW's 831-foot vertical radiator antenna tower

PHOTO-ELECTRIC "ARC EXTINGUISHER"

E&MP 94.037

Photo Electric Cells

no date

The instant a arc leaps across the safety gap at the base of WLW's 831-foot vertical radiator antenna tower, thus grounding the electrical energy collected from the atmosphere by the giant steel web, the photo-electric cell trained on the very center of the gap, sets in motion complicated relays which in turn shut off the transmitter's power for a split second and so extinguished the "power follow-up arc."

Were this arc not eliminated, virtually all of the station's 500,000 watts power would be drained from the tower into the earth.

The accompanying photograph [seen here] is typical of a "power follow-up arc" with the photo-electric arc extinguisher (to be seen in the background) disconnected.

With the extinguisher in operation such power follow-up is prevented and the discharge becomes but an instantaneous flash, after which the transmitter continues normal operation.

 


Original Caption by Science Service



National Museum of American History

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