ACL

1. A Chorus Line. A Chorus Line on Tour - Official Website, Every Little Step | Sony Pictures Classics.

2. Air Craft Landing light. The narrowest of PAR64 lamps. Because it is a 28V lamp, four fixtures are wired in series (4x28=112V).

GE - 4552 This lamp is a 250 watt, 28 volt PAR64 sealed beam. It is a PAR64 with a 7X8 beam spread, screw terminals and an overall length of 3.7 inches. It is rated at 25 life hours.
GE - 4559 This lamp is a 600 watt, 28 volt PAR64 sealed beam. It is a PAR64 with a 11X12 beam spread, screw terminals and an overall length of 3.7 inches. It is rated at 25 life hours.

Similar narrow beam, low voltage lamps are available in other PAR sizes, notably PAR56 and PAR46.

Posted to another forum:

From my PLSN column a while back:
http://www.plsn.com/index.php?option...2182&Itemid=40

In addition to designing and operating a large number of productions and tours, Howard [Ungerleider, best known as the LD for Rush] is very proud of a particular lighting moment in 1972. He attended a Marine auction and found a case of lamps called Marine Beacon Lights. They were 13-volt lamps the same size as a parcan. He put the lamps into parcans and wired eight of them in a series. “I found a smoke machine, and before my eyes I saw an amazing beam of light that appeared narrow, yet had a long throw.” He instantly thought, “Wow!” as he realized that he had created his own new fixture, now known as the ACL fixture.

Brad Schiller
www.bradschiller.com

See also ACL Harness.