Nonglare LEDs Make it Easier to See in the Tower

Emercon E70: Will be the first of its turbines to recieve the NL24 lights

Standard fluorescent lamps with an emergency lighting feature have been used to light the insides of turbine towers, but they suffer several drawbacks. For instance, installing them takes a lot of time and work, their maintenance intervals are relatively brief, and the lamps have a short service life. So when German turbine OEM Enercon wanted a more efficient way to illuminate its towers, the company turned to electrical-equipment firm Harting Technology Group. The two hit upon the idea of LED-based interior lighting.

LEDs (light emitting diodes) are more reliable which enhances occupational safety, and their cost of ownership is lower than fluorescents. They work the same way as semiconductor diodes, meaning they emit light when they are forward biased. The lamps have a long life, they rapidly switch from dim to bright, and are maintenance free. Better yet, their expected life is over 100,000 hours, which exceeds that of fluorescent lamps by a wide margin. However, to ensure the LEDs function properly, they must be kept dry. Harting’s challenge was to find a housing that offers good protection (IP 65), withstands rough handling, mounts on a heat sink or has one built in, and does not produce an irritating glare. A die-cast aluminum, power supply housing meets all requirements.

This rack holds Emercon LED lamps under test. Test results appear on the panel box (right).

The two firms then joined with Trade Wind Energy (TWE) to develop the new lamp which is now marketed by Enercon as the NL24.

Harting supplies the IP 65 LED lamp housing and mounting bracket for installation in the tower with system cabling to TWE, which manufactures the Plexiglas lenses and the lamp’s PCBs. TWE installs these items along with cabling into the power-supply housing.

The NL24 complies with several DIN and IEC standards. What’s more, system redundancy includes two interior LED lighting circuits in the tower and an acoustic warning if a circuit fails.