Every lighthouse light has its own characteristics – 1. the number of flashes per minute, 2. it’s range, which is dependent on intensity, lenses, and height, and 3. the number of beams from the light, plus other identifying features.
Flashes per Minute
The number of flashes per minute is regulated by the speed of rotation which is governed by the motor turning gears to drive the light around. The old heavy Fresnel lens lights sat on a bath of mercury and rotated in the early days from a hand-wound clockwork mechanism, later to be replaced by an electric motor, and later to be replaced altogether.
Enclosed lights such as the DCB-10 and DCB-36 (originally used as airport beacons) were only driven by electricity and gearing regulated the speed of rotation.
Each light in a certain area has a unique characteristic. Continue reading