We have collected answers to frequent questions on the following pages (Frequently Asked Questions). If you cannot find the answer to your special question or have more questions, please contact the respective sales or production site near you or write us a message using our Contact Form.

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What determines the service life of electronic ballasts?

The service life and therefore the reliability of electronic ballast is determined by the failure rate of the construction elements used. The temperature is a fundamental parameter along with the electrical specification and quality of the elements.

In order to ensure the specified service life, all components of the VS electronic ballasts are designed so that they can be operated beneath the authorised limit values. All units run through several test stations during the production process to rule out premature failure due to hidden faults. Tests are performed on the components and measurements of the relevant data for operation are taken among other checks. Before delivery, the electronic ballast is subjected to a final Burn-In-Test.

What's the difference between warm start and cold start technology?

Warm start: 

Correctly optimised ignition of fluorescent lamps whereby the cathodes need to be preheated on the ends of the lamps to the right temperature so that controlled discharge can take place. This achieves the best conditions for maximisation of the service life of fluorescent lamps.

Cold start: 

Ignition of fluorescent lamps without preheating the cathodes means that the emission materials from the cathodes are used up more quickly. 

Which advantage do electronic ballasts have in comparison to conventional ballasts?

Electronic ballasts produce high-frequency alternating voltages with frequencies of around 20 to 70 kHz. This means that the luminous efficiency of fluorescent lamps is increased by approximately 10% in comparison to 50/60 Hz operation with inductive ballasts. The high-frequency operation therefore allows the reduction of the system output without reducing the lamp's luminous flux

  • Low loss of output
  • Defined lamp conditions for a commission, operation and switch-off at  lamp fault
  • High reliability
  • Flicker-free lamp start and steady light
  • Longer lamp service life and longer maintenance intervals
How can I improve the EMC conduct of my luminaire?

In order to achieve good suppression of sparks and the best possible operational safety, the following points should be taken into account when laying the cables:

  • Keep cables between the electronic ballast and lamp (HF cables short (reduction of the electromagnetic influences). Lamp cables with a high potential must be kept short, especially on tube luminaires. These lamp cables are marked on the wiring diagram of the print plate with " * "
  • Mains and lamp cables are to be guided separately and not parallel to each other where possible. The distance between HF cables and mains cables should be chosen as large as possible, e.g. 5 - 10 cm (coupling interference between mains and lamp cables is avoided).
  • Lay HF cables at a distance (a few centimetres if possible) from earth metal surfaces (reduces capacitive coupling). If longer HF cables are unavoidable, such as for fluorescent tube lamps or for primary-secondary switching, twisting makes sense (the HF radiation is reduced).
  • Keep mains cables in the luminaire short (reduction of interference coupling).
  • The electronic ballast must have good contact to the metal luminaire case or be earthed using a PE connection. This must be laid as a separate cable and means that the HF leakage current is deflected better. The EMC becomes more favourable at frequencies above 30MHz.
  • Do not guide the mains cable too closely along the electronic ballast or lamps (this particularly applies to through wiring).
  • Do not cross over mains cables and lamp cables. If this is not possible, the crossover points should be designed at right angles where possible (avoid coupling mains and each is influences).
  • Cable recesses through metal parts should never be unprotected, and should always be provided with an additional insulation (insulation sheathing or recess bushing).
  • The luminaire body or parts thereof may never be "misued&quot as conductors nor have contact with the mains or lamp cables in any other way. e.g. bare cables, insulation too long, screws piercing through the installation or sharp metal edges. This can result in an acute danger to persons or the destruction of the ballast.
  • When looping-through several luminaires, e.g. with a 5-pole cable, you must always ensure that the two phases are never connected to the electronic ballast mains clamps instead of the group phase, the neutral cable and the protective earth cable. In case of any faults, switch off the electronic ballast in good time or immediately where appropriate.
How does the electronic ballast react if the lamp is defective?

VS electronic ballasts have an automatic identification feature and safety shutdown for abnormal lamp operating conditions. This can include defective lamp electrodes or high ohm lamp stretches through untight areas of a glass tube.

The critical operating condition at the end of the service life of fluorescent lamps is also detected. The resulting rectification effect leads to an increase in the lamp burn voltage around the electrodes and therefore to an increase in temperature in this area. The cause of this process is the loss of emitter material in the electrodes over the period of operation. This becomes particularly significant for the so-called End-of-Life phenomenon and when observing T5 and compact lamps due to the small tube diameter.

Können auch Fassungen mit individuellen Leitungen erworben werden?

VS bietet zusätzlich zum Standardportfolio auch kundenspezifische Produkte mit individuellen Leitungen, bei entsprechendem Auftragsvolumen, an. Setzen Sie sich mit uns in Verbindung!

In which temperature range can capacitors be used?

The normal temperature range is -25/40 °C to 85 °C

VS also offers special type B capacitors in the range of -40 to 100 °C.

Which capacitor types are there?
  • Type A capacitors = self-repairing capacitors without overpressure/disconnection device for errors.
    These are also referred to as unsecured capacitors.
  • Type B capacitors = self repairing capacitors with overpressure/disconnection device for errors.
    These are also referred to as hermetic, sealed or secured capacitors. 
How long is the service life of capacitors?
  • Type A = 30,000 hours
  • Type B = 50,000 hours
What is binning?

The LEDs are subject to production related variation in brightness, colorimetric locus (especially for white) and forwards voltages. In manufacturing, the LEDs are measured and compiled in groups with similar properties - this is a bin. The LEDs in the bin can be viewed as a homogenous class with respect to properties. The bin names and the authorised tolerance of the bins differs between manufacturers. Due to the fact that each production run defines the bins differently, the availability of certain groups is not guaranteed. The smaller bin is, the more difficult and expensive is procurement. It is therefore advisable to check the availability of the required selection before ordering.

What is the output of an LED and how can I compare it with other sources of light?

The output from an LED depends on the chosen operating current. As the operating current can be freely chosen and the Uf voltage is directed towards the current, the electrical output is a variable factor. For some modules, Vossloh-Schwabe provides the Pel depending on the current in the data sheet. This is why details of the wattage we are used to for incandescent lamps is not sufficient to draw a conclusion on the brightness or quality of the LED. A 4W LED is not necessarily "better" than a 1.2W LED. It may be the same LED under some circumstances, but just operated with different currents.

A better way of comparing the brightness is offered by the Lumen information for the light source or the efficiency in Lm/W (Lumen per Watt) to compare the energy efficiency.

The brightness of the LED does not increase proportional with higher operating currents but saturation of the semi-conductor takes place. This is why the efficiency of the LED (lm/W) does not reduce with an increasing operating current despite the increasing brightness.

What is an LED?

LED stands for Light Emitting Diode and describes a semi-conductor element which emits light at a defined wavelength when a direct current of electricity is provided. The emitted wavelength spectrum is very narrow.



What us a MacAdam-Ellipse?

Eine MacAdams Ellipse ist eine Ellipse im Farbraum, die die Gleichartigkeit eines Farbtones beschreibt. Sie ist ein Maß für die Homogenität von Farbort-Bins. Eine 7fache MacAdam Ellipse entspricht einem typischen ANSI-Bin, der die Farbortverteilung eine Leuchtstofflampe umfasst. Der Trend bei LED geht zu kleineren Macadam Ellipsen- zu 4fach bis 3fach Ellipsen. Die LED-Hersteller bieten entsprechende Selektionen an.

Quelle: Cree, Inc.

Empfohlene Links zur LED-Technologie und deren Anwendung findet man auf der Website der CELMA - Federation of National Manufacturers Associations for Luminaires and Electrotechnical Components in the European Union unter http://celma.org/home/index.php?module=publication

Besonders empfehlenswert ist der Leitfaden zur Auswahl der richtigen LED für Leuchten.

What do I need to consider when working with LED modules?

The safety and assembly instructions on the data sheet are to be observed when working with and assembling the LED modules. Precautions must generally be taken against ESD damages.

What are the disadvantages of the LED?

Disadvantages are proving to be the large variety of LEDs on the market, the fast technology cycle and the still relatively high price. Furthermore, thermal management needs to be taken into account in the lighting design. Simply replacing the current sources of light without adapting the luminaires is not possible in our experience.

What are the advantages of the LED?

In comparison to standard light sources, LEDs are very efficient and compact, switch on immediately, can be dimmed without any problem and have an excellent service life if thermal management is taken into account. They are free of pollutants, are very sturdy against mechanical influences and do not emit any dangerous ultraviolet or infrared radiation.

Which models of LEDs are there?

The semi-conductor chips are installed in a casing to be able to be processed mechanically and electrically. LEDs are available in different versions - through hole (5mm, 3mm, Piranha), CoB (Chip-On-Board) and in SMD technology. Vossloh-Schwabe offers LEDs for different applications in a variety of versions. Ready-to-use LED modules are available for use in LED luminaires.

Which norms are there for LED applications?

Eine zusammenfassende Übersicht über relevante Normen zu LED-Modulen, Vorschaltgeräten und LED-Leuchten findet sich unter celma.org (Link: http://www.celma.org/archives/temp/CELMA-ELC_LED_WG(LCB)001_CELMA_ELC_Guide_LED_related_Standards_3rd_Edition_Final_July2011.pdf)

How do I operate an LED module correctly?

LED are principally available in two versions - asConstant current controlledmodules and asconstant voltage controlledmodules. The constant current control modules do not have current stabilising switching on the PCB. The current is stabilised by the control gear. When choosing the right control gear, you must pay attention to the correct supply voltage range and the operating current. Typical series of products for this are the VS-PowerEmitter, LED modules for shop lighting, Mini / Line / Spot and M-Klass etc…

The constant voltage controlled modules require a steady voltage for operation. This voltage is usually 24V. There are additional electronics on the LED modules to regulate the current through the LED. Typical product series are the LEDLine Flex, LEDLine CoB or HighPower 24V CA System.

How do I operate an LED correctly?

Individual LEDs as semiconductor elements always require a stabilising current, i.e. the current flow through the LED must be limited at a defined level (operating current). The simplest scenario is when the series resistor is adapted to the forwards voltage  for LEDs with the low output, the operating current is typically at <50mA. For high output LEDs, it can be more than 1A. The maximum authorised operating current according to the data sheet may not be exceeded. In order to protect the LED from a thermal point of view and achieve a good service life, the actual operating currents are adapted lower (350mA, 700mA, 1050mA) than the maximum operating current and the respective application.

If the operating current is not limited, the LED can destroy itself due to overheating. The forwards voltage reduces when the LED heats up. This reduces the resistance and the stronger current flows which leads to a further reduction of the voltage and increased heating. If you do not restrict the supply of current, the LED overheats due to the increasing current.

How do I dim LED modules from Vossloh-Schwabe?

LED modules can be very easily dimmed using the pulse width modulation (PWM) of the operating current. There are the corresponding dimmable ballasts for the constant current system. In the 24V direct voltage system, additional components from the DigiLED series are required.

How do I ensure a good thermal design?

Bei Einsatz von Hochleistungs-LEDs ist ein thermisch gutes Design unabdingbar. Nur mit einem optimierten Design ist eine Leuchte mit einer guten Lebensdauer und Performance zu garantieren. Die Temperatur der LED im Betrieb determiniert ihre Lebensdauer und das Helligkeitsniveau. Als Faustregel gilt - Die gesamte aufgenommene elektrische Leistung muss auch als Wärme an die Umgebungsluft abgeführt werden. Dabei muss sichergestellt werden, dass die im Datenblatt angegebene maximale tc-Temperatur (Temperatur der Platine) des LED-Moduls nicht überschritten wird. Eine ausführliche Anleitung zum thermischen Design von LED-Leuchten findet sich auf der Website http://www.vs-optoelectronic.com/ger/produkte/ledtech/201.php

How are details of the service life of LED modules provided?

The LED semiconductor loses its ability to generate a light overtime. Its ages. This process heavily depends on the temperature of the semiconductor. The higher the temperature, the quicker the semiconductor ages. LEDs have the longest service life out of all artificial sources of light if the temperature of the semiconductor is kept at a defined working level. This is why corresponding heat management is essential in a luminaire. A limit value of 70% is generally tolerated as the ageing limit - this is the L70 value. This means that when the LED has lost 30% of its original luminous current, the installation should be renewed and the end of the service life is reached. Vossloh-Schwabe states the service life and the corresponding parameters (temperature and operating current) in the data sheets.

Example of a service life curve in correlation with the temperature.

When will magnetic ballasts for fluorescent lamps be prohibited in Europe?

There is no prohibition on magnetic ballasts!

Only ballasts in classes EEI=B2 and EEI=B1 may no longer bs used in Europe from 2017.

VS already has extra low-loss magnetic ballasts in class A2 for the standard wattages 18 - 58 Watt in the product range.

What do the type names mean for the VS ballasts?
LStandard ballast for fluorescent lamps
LN Low-loss ballast for fluorescent lamps
SL Ballasts for a special voltage  (combination of transformer with ballast)
NAH Ballast for sodium vapour lamp
J Ballast for metal halide lamps
Q Ballast for mercury lamps
NA Ballast for low pressure sodium vapour lamp
STR Magnetic transformer for low-voltage lamps
What does the tw mark on the ballasts mean?

tw refers to the maximum authorised winding temperature of the ballast which the insulation withstands under continuous operation and the nominal conditions.

The standard ballasts from VS have tw130.

VS also has special units with tw140 and tw150 in their range so that the customer can use them in luminaires with critical thermal conditions.

Will magnetic ballasts for high-pressure lamps be prohibited in Europe?

There is no prohibition on magnetic ballasts in Europe !

Only an energy classification has been passed. Irrespective of the technology, all ballasts must comply with the corresponding loss values.

All HID ballasts from VS already fulfil the limit value until 2017 ( A3 mark  ).

In addition, VS already has a complete product range of all wattages in the program which comply with the limit values from 2017 (A2 mark).

How high is the leakage current for magnetic ballasts?

The leakage current for magnetic ballasts is < 0,1 mA.

How high is the failure rate of magnetic control gears?

The failure rate is less than 0.02 % by 1,000 operating hours.

How long is the service life of magnetic control gears?

The service life is a minimum of 100,000 hours when operated under the nominal condition.