A parabolic reflector, driven by an electric motor, revolves around a continuously illuminated bulb on the vertical axis of the beacon creating a powerful beam of light travelling through 360 degrees.
These units are available with either a filament or a tungsten halogen bulb. In general, this type of beacon has a greater degree of light output than other models but this is reduced as the parabolic reflector only illuminates one given point at a time.
Operating through an internal circuit, which simply cycles the bulb On, and Off. These types of beacons generally give a much lower light output as it takes longer for the bulb to fully illuminate itself.
The effective brightness can be increased by use of a Diotropic (Fresnel) lens which is placed over the internal cap, capturing the light emitted, magnifying and directing it to create a more effective warning signal. In terms of light coverage this type of beacon is more efficient as it illuminates the total surface constantly through 360 degrees.
Static Filament (Continuous) Beacons
These units are identical to Flashing Filament beacons with the exception that they do not operate through an On, and Off cycle. When the unit is energised the light source stays permanently ‘On’.
The main advantage of this type of beacon is that the light can be controlled by a separate source i.e.. a control panel, giving the unit more flexibility.
Xenon (Strobe) Beacons
A discharge capacitor operating through a converter circuit ignites xenon gas inside a tube creating a brilliant flash of light. Xenon gas ignites virtually instantaneously so maximum brightness is obtained immediately. This signal can be improved further by the use of a Dioptric (Fresnel) lens as described earlier. In some Moflash models a ‘Double Flash’ option is also available this extends the signal duration making it more noticeable to the human eye. See X88, X201-200, X401-400, X501-500.
Xenons have an added advantage of low current consumption combined with long life. The tube life of a xenon beacon is approximately 5 million flashes. These units are the most efficient available incorporating a 360 degree light output with the brightest and most effective visual signal.
A light emitting diode (LED) is a semiconductor device that emits visible light when an electrical current passes through it. The four major benefits of LED technology incorporated into warning beacons are:
- Low power requirement
- High efficiency
- Very Long Life
- Multiple colour signal options in a single beacon enclosure.
Moflash offer a range of LED options, from beacons containing 8 off LEDs up to 144 off LEDs in a single enclosure. They can be set in various modes of operation from Flashing, Static and Rotating. Some beacons have a combined Audible & Visual option. Ethernet compatible and PLC controllable beacons also make up the range along with high ‘Ingress Protection’ enclosures.
Levels of Brightness
Brightness depends upon the type of beacon chosen, the rated power output of the unit i.e. Watts and Joules, the distance that the signal is observed from and the dome colour of the beacon used. In general, if the viewing distance is doubled, the light intensity observed is reduced to a quarter and if the distance is quadrupled the light intensity is reduced to a sixteenth.
Beacon Lens Colours
The intensity of the light can be greatly reduced as it passes through the dome of the beacon. The extent of this reduction is dependent upon:
- The type of light source used i.e. conventional Filament (Incandescent) Bulb, Tungsten Halogen Bulb, Xenon Tube or LED.
- The colour of the beacon lens that is used.
Lens colours available are shown in the below table:
The next table gives an indication of the percentage of light that will pass through the beacon dome for different light sources and dome colours.
Dome colours convey different messages to the observer:
|RED||Serious Danger - Act now!|
|AMBER||Warning proceed with care|
|GREEN||Ok proceed as normal|
|Blue||Specific process notice/warning|