Distance between converter and luminaire
The converter can be installed some distance away from the luminaire. However, the cable cross-section must of such a size that at least 23V reach the luminaire.

Connecting LED.next luminaires to EIB/KNX and other bus systems poses no problem at all. Please see the technical notes in this catalogue for important information on integrating LED.next luminaires into EIB/KNX and bus systems.

You can obtain texts for calls for tender regarding Nimbus luminaires from projektabteilung@nimbus-group.com

LED.next luminaires achieve a working lifetime of up to 50,000 hours and more. Even then, they continue to shine at around 70 % of their normal output. Although there may be a slight colour shift, it is almost imperceptible. Low-price LED products do not usually have such a long lifetime, as the heat transfer away from the LED is often not sufficient. Our fail-safe technology therefore allows very long maintenance intervals.

The use of LED luminaires for lighting raises no concerns as far as damage to eyes is concerned. Unlike many of its competitors, Nimbus mainly uses low power LEDs. These Nimbus LEDs fall into the safest category, LED Class 1, and since the middle of 2008 have been categorised as a light source belonging to the classical lighting media. However, because of the high luminance (and as with other, conventional light sources) one should not look directly into a LED for a longer period of time.

What happens if, against all expectations, a LED in a luminaire is defective? Does the whole luminaire need to be replaced? In the unlikely case of a failure of individual LEDs or of a whole luminaire, all Nimbus LED products can be repaired/serviced by Nimbus or by an authorised specialist dealer / support centre partner. You have a statutory right to the repair of all defects in connection with any faults occurring during the statutory guarantee period under EU law. Even after the guarantee period has expired, repairs are of course still possible. This involves replacing PCBs or individual LEDs on your premises our in the workshop. During the repair process, the replacement components are adjusted as far as possible to achieve the right light colour and brightness.

Our experience, which covers the use of several million LEDs, has shown that a total failure is very unlikely. The statistical failure rate is 2 LEDs per million installed.

Illustrations and scale drawings of all Nimbus products can be downloaded from www.nimbus-design.com

In comparison to many conventional lamps our LED luminaires have a much higher level of efficiency. On the one hand, this is the result of the LED being 5–6 times more efficient than a light bulb, and on the other hand, it is due to the fact that the light from a LED does not have to be directed out of the luminaire via reflectors, and so the light output of a 10 watt LED luminaire is roughly equivalent to that of 100 watt light bulb or a of a 50 watt halogen lamp.

A LED luminaire can be disposed of in the same way as a conventional lamp. The PCB is treated as electronic waste for disposal purposes. 99 % of the PCB is aluminium and can be recycled. Unlike low-energy lamps, a LED contains no mercury and is therefore not treated as special waste.

A blue-emitting LED is used for generating white light. This generates a white spectrum with the help of a fluorescent material (phosphorous) – like with a fluorescent lamp. Nimbus uses high-quality, warmwhite LEDs with a colour temperature of 3000K. LED lamps give off full light immediately after being switched on.

The LEDs used by Nimbus have a colour rendering index (RA/CRI) of > 80, thereby meeting the provisions of the most frequently applied guidelines for office lighting.

Nimbus uses high-quality, warm-white LEDs with a colour temperature of 3000K. The colour is similar to that of a halogen lamp. Colour temperatures between warm-white (3000 kelvin) and cold-white (5000 kelvin) can also be realised on request.

Switching on and off frequently
You can switch a LED luminaire on and off as often as you wish. Switching a LED luminaire on and off frequently will not damage it.

Load on the converter
The load placed on a LED luminaire converter may always be lower than the rated wattage, but the rated wattage may never be exceeded. That is to say, you can place a 10W load on a 60W converter.

LED luminaires are being used more and more for general lighting. The high-quality warm-white LED light developed by Nimbus was designed to be used for general lighting. Nimbus LED.next luminaires are perfectly suited for use in the professional area (offices and workplaces) where people should be able to work without tiring, as well as for the home with a light similar to that of a halogen lamp. At the beginning of 2009, Nimbus lit an office building for the first time entirely with LED luminaires – over 2500 of them. Thanks to their energy efficiency, LED luminaires revolutionised the lighting market and their impact will be a lasting one.

The useful lifetime of a LED strongly depends on the ambient temperature to which it is exposed, with temperatures on the cool side being beneficial to the length of its lifetime. Steps should be taken to ensure adequate air circulation around external converters.

The luminaire‘s degree of protection also needs to be considered during planning when dealing with LED luminaires. The luminaires of the Modul Q and Modul R Aqua-series, for example, with degree of protection IP44, are suitable for use in damp atmospheres.

You can receive assistance with light planning and light calculation from lichtplanung@nimbus-group.com

Photometric data files can be downloaded in ldt format from www.nimbus-group.com.

The useful lifetime of LED luminaires is very long and can reach up to 50,000 hours. Even then, a LED does not fail like other lamps, it merely loses light output over a period of time during which there is little change in the subjectively perceived brightness. The failure rate is therefore much lower than for compact fluorescent lamps. The installation conditions contained in the mounting instructions should be observed if the installed components are to achieve their rated useful lifetime.

LED luminaires can be mounted on practically any material (including wood), as the temperature is no higher than 70° C. All Nimbus LED luminaires bear the F symbol and can be mounted on or in materials whose flammability lies within the normal range. Please see the mounting instructions for the installation situation for the individual LED luminaires.

Illustrated installation and assembly instructions can be downloaded in pdf format from www.nimbus-group.com.

In view of the discussion on CO², energy efficiency is set to grow in importance. According to the German Electrical and Electronics Manufacturers‘ Association (ZVEI), 3.2 billion kWh of energy and 1.9 million tonnes of CO² could be saved every year in Germany on office lighting alone. One measure aimed at supporting such saving efforts is the EuP Directive 2005/32/EC (Eco-Design Requirements for Energy Using Products) which came into force in September 2009: Among other things, the directive envisages inefficient products, e.g. for home and office lighting, being successively taken from the market. In comparison, using Nimbus LED luminaires can save up to 70 % in energy costs. Although the purchase price of a Nimbus LED.next luminaire may currently be around 20–30 % higher than that of a comparable conventional Nimbus luminaire, the higher purchase price will have paid for itself within just a short time, thanks to the significantly lower operating and maintenance costs. Nimbus LED.next luminaires are also outstanding in terms of their fixture efficiency and their long, fully maintenance-free lifetime. The luminous flux per watt of the current LED is much higher than that of halogen low-voltage light and at 3000 kelvin colour temperature is currently between 80–90 lm/W. Replacing light bulbs and halogen lights with LED.next technology represents an important contribution to sustainability.

LED afterglow
LED luminaires can continue to glow a short time after being separated from the power supply. This has no effect on the quality and lifetime of the luminaire.

All Nimbus LED luminaires can be operated (if a suitable converter is used) with direct current in emergency power systems with central battery back-up according to VDE 0108/VDE 0100/Part 718.

Nimbus LED luminaires are designed for 24V direct voltage (DC). The LED PCBs have no special protection against short-circuits/overload and excessive temperature. It is therefore important with all LED modules to pay particular attention to the correct polarity (+/-) of the connections. Modules which are wrongly connected heat up and can be destroyed as a result.

LEDs do not emit UV/IR light in their beams and therefore no heat is given off from the luminaire surface. They are therefore highly suitable for lighting in situations where objects need to be preserved, e.g. in museums or galleries.

Light emitting diodes are semiconductor components which can be dimmed (PWM) or dynamically activated in a most efficient fashion. Please see the technical notes in this catalogue for important information on the correct activation and dimming of LED.next luminaires.

Thanks to the way in which they are constructed, LED luminaires are protected against vibration. However, the components in the LED modules may not be subjected to mechanical stress and the circuitboard conductors may not be damaged.

How does the luminous flux change in LED products from one LED generation to the next and what does this mean for the published lighting measurements and parameters? Unlike all other lighting media, LEDs are in a constant optimization process, comparable to that in the microchip industry. Their performance and efficiency is getting better all the time thanks to constant development. We pass these advantages on to our customers by always installing the latest generation of LEDs in our luminaires. The typical measured values of our LED luminaires can therefore change. These modifications are performed without advance notification. Up-to-date data records are always available for download on our homepage at www.nimbus-group.com to assist you in your planning.

Besides the colour temperature, the long intervals between maintenance and the extremely compact construction represent significant advantages of LED technology. Thanks to lens optics and dimples, light can be optimally directed onto the working surface where it is needed, whereby the light output of the LED can be used much more efficiently. LED luminaires are also extremely resistant to knocks and vibration.

A major advantage over halogen low-voltage lamps is the fact that the light contains no IR/UV rays and that there is therefore no heat radiation. The energy efficiency of LEDs is well over twice as high as that of halogen low-voltage technology.

Heat development of a LED luminaire
The temperature on the back of a LED luminaire is no higher than 70 °C. However, care must always be taken with LED modules to ensure correct polarity (+/-) of the connections. Modules which have been wrongly connected heat up and can be destroyed as a result.