street lighting knowledge Base series I

lamp compartment which is covered by a transparent cover glass towards the front portion. (reference http://www.urbislighting.com/knowledgebase.php?cat=2&archive=1&sid=2005_3_7)
Making sure that luminaires remain as maintenance free as possible is very important to lighting engineers, and there are many different ways to seal the optical and control gear compartments to achieve this. We asked Bryan Shortreed, Engineering Support Manager at Urbis Lighting, about the different options available.

Why is keeping the optical compartment sealed so important?

"For a luminaire optical compartment, the choice is simple. If there is any ingress of dirt or moisture then the performance of the luminaire is affected, as the maintenance factor is reduced.

Additionally, there will also be a requirement for cleaning the inside of the optic, which will increase the time taken for maintenance. Therefore, it makes sense to choose a luminaire with an optical compartment tightness of IP66."


control gear compartment
Control gear consists of either a ballast, ignitor and capacitor(chinese reference ) for conventional control gear or an electronic ballast. There are often other electrical components such as a photocell or monitoring device.

The life of an electrical component is strongly related to the temperature at which it runs. If we take the conventional ballast as an example, the ballast manufacturer will specify a maximum temperature (TW) at which the ballast should be operated to give it a life of 10 years. Typically, if the ballast were to run through its life at 10 degrees above this figure then the ballast life would probably be halved. Similarly, if the ballast were to run cooler than the TW value through its life, then it would be reasonable to expect the ballast life to be significantly improved. All of the other electrical components behave in a similar manner."