The Los Angles City Hall was damaged in the Northridge earthquake in 1994. Project Restore, a non-profit restoration and preservation organization, spearheaded fundraising and planning for refurbishing the landmark building called the ‘The Crown Jewel of Los Angeles’. The restored beacon was helicoptered into place atop the building’s 29-story tower on 8 September amid mass media coverage.
Combining historical restoration with an opportunity to upgrade to a modern light source, Phoebus designed and engineered a number of improvements. The beacon was refitted to accommodate a 2.5kW HMI metal halide short arc discharge lamp. The original glass mirror was removed and a metal mirror was installed to accommodate the increased heat of the new HMI Lamp. Phoebus’ in-house engineering staff re-aligned the beacon’s photometrics to accommodate the new light source and mirror. A forced air cooling system was added incorporating two brass-domed intake ports and two fan-forced exhaust ports and includes a thermostatic over-temperature shut-down system. Safety interlocks were added to prevent the unit from operating with the lens cover open. The beacon’s red glass lens was removed and the unit was returned to its original clear lens color using tempered soda lime plate meeting ETL shock standards. A dual-output magnetic power supply was custom built for the unit which allows the beacon to operate at full intensity or at a reduced light level. Remotely mounted in the City Hall tower, the internally-cooled power supply enclosure contains an integrated control panel to operate all of the beacon’s functions from its location, including Master Power Controls, Lamp Auto-Strike Activation and Shut-Down, Lamp Illumination Intensity Control (Full Intensity / Reduced Intensity) and Beacon Lamp House Rotation.
The beacon’s rotating mechanism, commutator and motor drive were completely rebuilt including a new housing and supports matching the original 1928 design. With the lamp house and motor housing refitted with upgraded water seals, the completed beacon went through several days of extensive ETL testing at the Phoebus manufacturing facility in San Francisco during rare 90° weather. The re-fitted beacon easily passed cooling, water and glass breakage tests and received ETL certification.
