Introduction
The advantages of LED lighting are becoming increasingly well known. The solid state technology requires nearly no maintenance, regularly consumes only one third of the energy of the traditional HID light sources, and offers instant on, white light. By populating a total cost of ownership (TCO) calculation with their own data and costs, operators can readily estimate their expected energy and maintenance savings.
Yet even when their own calculations tell a favorable payback story, some operators still hesitate to invest in LED lighting, mainly because the cost of acquisition for LED fixtures typically exceeds that of fixtures with traditional light sources. A miscalculation, a bad installation, any unforeseen cost or quality problem can be an expensive proposition and eliminate anticipated savings. Having little experience with LED technology, some operators have opted to forego the benefits because they consider adopting the technology too high a risk.
Mitigating risks and managing concerns
Scott Fredrick, chief executive of Phoenix Products Company, Inc., manufacturer of LED lights for port applications, understands. “As a manufacturer, we had the same concerns when we developed our ModCom™ LED floodlight,” he says. “It was a major investment, and we had to be sure the technology was ready for these applications.”
For Phoenix, it was a matter of managing risk through education, in house testing, third party verification, and beta testing. With LED experience in other industries and decades of experience in general floodlighting at ports, Phoenix knew the keys to a successful application of LED technology on port cranes would be:
- maintaining sufficient and uniform light levels
- managing vibration to maximize the fixture life
- ensuring the longevity of the light engine in a marine environment
- managing thermal properties to maximize light engine life
First and foremost, the fixture should provide ample illumination evenly in the application. Phoenix determined that an output of over 20,000 lumens was required from its LED floodlight to replace a 1,000 watt high pressure sodium fixture. Operators should be able to get a firm idea of how a fixture will perform by requesting a lighting study from their LED lighting manufacturer. Sample specifications from similar applications may also be available to help clarify goals.
Generally speaking, operators are looking for 200 lux minimum at any point 10 meters from the centerline of a crane. A common evenness goal would be 3:1 uniformity within a 3 meter radius; in that area, the maximum light level would be no greater than three times the minimum level in the space. A common performance goal specified for LED fixtures is an L70 of 50,000 hours. This figure indicates that, at 50,000 hours, the fixture would provide 70 percent of its initial lumen output.
Operators may also want to specify the color temperature of the light according to their preference. With crane operator comfort in mind, several specifications have been written with 5,500 degrees Kelvin at a maximum, which would be similar to daylight, as opposed to being ‘warm’ or ‘cool’ in color. Lighting fixtures on port cranes are subject to constant vibration and the corrosive elements of a marine environment. Standard for any fixture in this environment are corrosion resistant materials and finishes, such as low copper content aluminum, marine grade paint, and stainless steel hardware.
In addition to contributing to corrosion, residue left by saltwater condensation and evaporation can degrade optical performance. Terminal operators should ask LED fixture manufacturers to discuss how the fixture, light engine and optics are protected from the effects of saltwater and vibration. In its ModCom floodlight, Phoenix uses circuit boards conformally coated with silicone approved by the LED manufacturer.
The ModCom also incorporates fully potted drivers, sealed optics (IP67), and stranded wires with protective sleeves at wear points. Phoenix tests its fixtures against the extreme vibration standards of the makers of the world’s largest earthmoving equipment, mining draglines and shovels. Phoenix fixtures have successfully performed in these mining applications for nearly two years.
To read the full article download PDF
