FAQ - Emergency led tube,VDE, UL,TUV led tube
内页横幅五
内页横幅五

FAQ


 

1.     LEDs

LEDs are Light Emitting Diodes: electronic components that convert electrical energy directly into light through the movement of electrons inside the diode material. LEDs are important because, due to their efficiency and low power consumption, they have become a substitute for most conventional light sources.


2.      SMD LED

The Surface Mounted Device (SMD) LED is 1 LED on a circuit board, which can be in mid-power or low power and is less sensitive to heat generation than a COB (Chips On Board) LED. SMD LEDs are usually mounted on a Printed Service Board (PCB), a circuit board onto which the LEDs are soldered mechanically. When a small number of LEDs with relatively high power are used, the heat distribution on this PCB is unfavourable. It is better to use a mid-power LED in that case, because the heat is then better divided between the LED and the circuit board. The circuit board must consequently also lose heat. This is achieved by placing the PCB on an aluminium profile. High-quality LED lighting products have an aluminium profile on the outside in order for the ambient temperature to cool the lamp. Cheaper variants are equipped with a plastic casing, since plastic is cheaper than aluminium. These products only offer good heat dissipation from the LED to the base plate. If the aluminium does not lose this heat, cooling remains problematic.


3.      Lm/W

The lumen per watt (lm/W) ratio indicates the efficiency of a lamp. The higher this value, the less power is required to produce a certain amount of light. Please note if this value is determined for the light source or luminaire as a whole or for the LEDs used in it. LEDs themselves have a higher value. There is always some loss in efficiency, for example when drivers and optics are applied. This is the reason why LEDs may have an output of 180lm/W, while output for the luminaire as a whole is 140lm/W. Manufacturers are required to state the value of the light source or the luminaire. The output of the luminaire has priority over the light source output, because LED luminaires are assessed as a whole


4.      Power factor

The power factor indicates the relationship between the power input and the power used to enable the LED to function. There is still a loss in LED chips and drivers. For example, a 100W LED lamp has a PF of 0.95. In this case, the driver requires 5W to function, which means 95W LED power and 5W driver power.


5.      UGR

UGR stands for Unified Glare Rating, or the glare value for a light source. This is a calculated value for the degree of luminaire blinding and is valuable for assessing comfort.


6.      CRI

The CRI or Colour Rendering Index is an index for determining how natural colours are displayed by the light of a lamp, with a reference value for a halogen or incandescent lamp.


7.      SDCM

Standard Deviation Colour Matching (SDMC) is a measuring unit of colour difference between different products in lighting. Colour tolerance is expressed in different Mac-Adam steps.


8.      DALI

DALI stands for Digital Addressable Lighting Interface and is applied in light management. In a network or stand-alone solution, each fitting is allocated its own address. This allows each lamp to be individually accessible and controlled (on – off - dimming). DALI consists of a 2-wire drive which runs apart from the power supply and can be expanded with motion and light sensors among other things.


9.      LB

The LB standard is increasingly mentioned in lamp specifications. This gives a good indication of quality, both in terms of light recovery and LED failure. The ‘L’ value indicates the amount of light recovery after a lifetime. An L70 after 30,000 operational hours indicates that after 30,000 functional hours, 70% of the light remains. An L90 after 50,000 hours indicates that after 50,000 operational hours, 90% of the light is left, thus signalling much higher quality. The ‘B’ value is also important. This relates to the percentage that may deviate from the L value. This may for instance be due to the failure of LEDs.  L70B50 after 30,000 hours is a very common specification. It indicates that after 30,000 operational hours, 70% of the new light value is left, and that a maximum of 50% deviate from this. The B value is based on a worst-case scenario. If the B value is not mentioned, B50 is used. PVTECH luminaires are rated L85B10, which indicates the high quality of our luminaires.


10.   Motion detectors

Motion detectors or presence sensors are an excellent combination to be used with LED lighting, because they can directly turn on and off. This type of lighting is ideal in a hall, or a toilet, but it can also be used in a variety of industrial spaces and warehouses where people are working. Most LED lights are tested to survive 1,000,000 switching times, which is good for years of use. One tip: it is preferable to apply a motion detector separate from the luminaire, since the light source is likely to last longer than the sensor. Moreover, a defective sensor can prevent additional cost savings.


11.   What does operating temperature mean?

The operating temperature is a major influence on the lifespan of LEDs. The recommended operating temperature depends on the selected cooling, driver, LEDs and housing. A unit must be judged as a whole, rather than its components separately.  After all, the ‘weakest link’ can be the determinant. Low temperature environments are ideal for LEDs. Cooling and freezing cells are particularly suitable, because the LEDs can get rid of the heat well. Since less heat is already generated with LED than with conventional lighting, cooling will also need less power to maintain its temperature. A win-win situation! In relatively warm environments, the situation becomes different. Most LED lighting has a maximum operating temperature of 35° Celsius, PVTECH lighting goes up to 65°C!


12. Why are lenses used more often in line lighting than reflectors.

LEDs have a focused beam of light, unlike traditional luminaires that spreads light on its surroundings. When LED luminaires are provided with reflectors, much of the light in the centre of the beam leaves the system without even coming into contact with the reflector. This reduces the degree of modulation of the light beam and can be the cause of blinding. Lenses help to guide almost any beam of light emitted by the LED.


Emergency led tube,VDE, UL,TUV led tube
Emergency led tube,VDE, UL,TUV led tube

Emergency led tube,VDE, UL,TUV led tube

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CONTACT US

 

E-mail:sales@pvtech.com.cn

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