what is Illuminance E ?

The unit of measurement is the lux [lx]: E = F / A F = luminous flux in lumenensA = area illuminated in m2 Illuminance E is the ratio between the luminous flux and the area to be illuminated. An illuminance of 1 lx occurs when a luminous flux of 1 lm falls evenly on an area of 1 m². Based on the definitions for illuminance luminous intensity and solid angle W = A/r2, we obtain the following formula for illuminance: E = I / r2Photometric inverse square law r = distance of the light source to the object in mA = area illuminated in m2I = luminous intensity in Candela It is assumed that the light falls perpendicular to the surface it illuminates. If the surface is at an angle a then E = I/r2 must be multiplied by cos a.

What is HMI lamps

HMI lamps are metal halide lamps with an increased load on the bulb wall and very short electrode gaps to improve luminous efficacy and colour rendering, at the expense however of lamp life. These lamps are ideal for applications such as theatre lighting, endoscopy, filming and TV recordings under daylight conditions (colour temperature = 6000K).These lamps range in wattage from 200 W to 18 kW.

what is Halogen cycle

Halogen cycle The main characteristics of an incandescent lamp, namely its luminous efficacy and service life, are determined to a large extent by the filament temperature. The higher the filament temperature, the higher the luminous efficacy but the shorter the life of the lamp. This reduction in the life of the lamp is a consequence of the rate at which tungsten evaporates from the filament. This rate increases rapidly with increasing temperature. Not only does it blacken the inside of the bulb, it causes the filament ultimately to burn out. This blackening of the bulb can be effectively countered by adding halogens to the filler gas to prevent evaporated tungsten from depositing on the bulb wall by a "halogen cycle process". The tungsten that evaporates from the filament during normal operation migrates towards the bulb wall by diffusion or thermal convection In the temperature region <1400>1400 K) where they dissociate back to tungsten and halogen, leaving the halogen to repeat the cycle. Some of the tungsten is transported back to the filament, but not to its original location. The "normal halogen cycle" therefore merely prevents the bulb from blackening, it does not extend the life of the lamp. The lamp comes to the end of its life when the filament melts at one of its hot spots.

Pulse ignition systems

For HS, HI and C-HI lamps - PZ 1000 K / PZ 1000 K P20 For high-pressure sodium lamps (HS), metal halide lamps (HI) 35 -1000 W and ceramic discharge tube lamps (C-HI) 35 - 400 W Ignition voltage: 1.8 - 2.3 kV or 4.0 - 5.0 kV, respectively No. of pulses: 2 per mains period Load capacitance: 20 -1000 pF Suitable ballast types: NaHJ ... PZ/PZT with special winding tapping point, whose position is determined by the magnitude of the ignition voltage


For HI lamps - PZI 1000/1 K and PZI 2000/400 V 1.2 kV For metal halide lamps (HI) with an ignition voltage up to 0.9 kV or 1.3 kV, respectively. No. of pulses: 1per mains period Load capacitance: max. 10,000 pF Suitable ballast models: Q...

Edison bases are predominantly used for mercury vapour lamps (HM)

Edison bases are predominantly used for mercury vapour lamps (HM)

Bases for the most widely used HI and HS lamps

Bases for the most widely used HI and HS lamps

Lampholders for high-pressure discharge lamps

Metal halide and high-pressure sodium lamps feature extremely different bases, which include RX7s, Fc2, G8.5, GX10, G12, PG12, E27 and E40, depending on whether the lamp is single- or double-ended. All lampholders are subject to the same typical conditions found with discharge lamps: high ignition voltages and temperatures. The high start-up currents deserve particular attention in lampholder design. This is also reflected by the insulation materials, which are usually solid ceramics or heat-resistant plastic (e.g. PPS - polyphenylene sulphide). Depending on the lamp´s requirements (voltage, current, temperature, etc.), silver, nickel and copper alloys with thick nickel coatings are used as conductors. The luminaire regulation IEC 60598-1, in accordance with EN 60598-1, defines the safety requirements with regard to ignition voltages in connection with creepage and air clearance distances.

Special care must be taken to ensure that lampholders are approved for discharge lamps when using high-pressure lamps with E27 and E40 Edison bases. Lamholders that are suitable for this purpose are marked with a maximum value of "5 kV" and comply with the creepage and air clearance distances required by EC 60238 and EN 60238 (VDE 0616 part 1). The lampholder regulations governing special lampholders, IEC 60838-1 and EN 60838-1 (VDE 0616 part 5), apply analogously to all other base systems. The high ignition voltage pulses also place special demands on the conductors. In practice, silicone-insulated conductors with an outer diameter of 3.6 mm have proved suitable for discharge lamps. Silicone-insulated conductors with a glass-silk lining with a diameter of 7 mm should be used for lamps with an immediate hot restart function.

Circuit diagrams for high-pressure sodium lamps and metal halide lamps

Superimposed ignition of HS and HI lamps


Pulse ignition of HS and HI lamps



Power reduction of HM lamps



NHT-SDX lamps 100 V/200 V (autotransformer for European voltage)

Mandatory regulations of HID Ballast

DIN VDE 0100
Regulations for the installation of power current facilities with rated voltages of up to 1000 V
EN 60598-1
Luminaires - part 1: general requirements and tests
EN 61347-1
Devices for lamps - part 1: general and safety requirements
EN 61347-2-9
Devices for lamps - part 2 - 9: special requirements for ballasts for discharge lamps (except fluorescent lamps)
EN 60923
Ballasts for discharge lamps - performance requirements
EN 55015
Maximum values and methods of measurement for RFI suppression in electrical lighting installations and similar electrical appliances
EN 61000-3-2
Electromagnetic Compatibility (EMC) - part 3: maximum values - main section part 2: maximum values for mains harmonics (device input current up to and including 16 A per conductor)
EN 61547
Installations for general illumination purposes - EMC immunity requirements

Click on the image to get a PDF-file with the assembly instructions of electronic converters.

Power reduction with HS and HM lamps

The lamp wattage can be reduced by operating the ballast at a higher impedance value, higher than the rated value. The lamp manufacturer´s specifications must be observed in doing so to avoid shortening the lamp´s service life. The lamps should be started at the ballast´s rated impedance and only switched down to reduced operation after a period of at least five minutes.
The impedance value can be altered by using an additional ballast (high-effort option) or by using a switchable ballast (low-cost option). These ballast models can be switched using either a modern, time-controlled electronic power reduction switch, which is equipped with an additional control conductor (230 V), or a power reduction switch with a constant incentive rate setting (no control conductor).

The construction of power reduction switches with control conductors differs according to the selected increase in impedance. PW devices are suitable for additional ballasts and PU devices for switchable ballasts.

Ballasts for HM lamps

Even in the event of major mains fluctuations (94 -106 % of the rated voltage), the ballast must not fall short of the no-load voltage specified by the lamp manufacturer nor exceed a fixed short-circuit current.

The start-up current must be high enough to ensure that at least 90 % of the lamp´s operating voltage is achieved within 15 minutes.

Electromagnetic ballasts for HI and HS lamps

As the lamp manufacturer´s reference values regarding lamp current and voltage are generally identical for metal halide (HI) and high-pressure sodium lamps (HS) of the same lamp wattage and the impedance values required for the ballast are also identical, the same ballasts can frequently be used for both lamp types. It should be remembered that HI lamps react sensitively to impedance deviations from the rated value with appreciable colour changes. Vossloh-Schwabe ballasts therefore comply with the lamp´s narrower tolerances. Moreover, the maximum peak direct current value must be observed when operating HI lamps. This value is not specified for HS lamps; instead, the maximum stated start-up current must not be exceeded.
In order to keep the temperature of the luminaires and the electrical values of the lamps within tolerable limits, the impedance of the ballasts must remain constant over the entire service life. A so-called service life test provides proof of this requirement having been met.

HI and HS lamps constitute a special case in terms of thermal testing. In rare cases, a safety risk can occur at the end of the service life of lamps fitted with external bulbs. The safety risk is caused by the so-called lamp rectifier effect, which can lead to overheating of ballasts, ignitors, lamphoders and conductors and can therefore destroy the luminaire. Against this background, the luminaire standard EN 60598-1 "luminaires; part 1: general requirements and tests" has been supplemented by tests concerning this safety risk. As a result, since 1September 2002, it has been illegal to market luminaires that do not comply with the new regulations, i.e. that do not limit the degree to which a lamp heats up in the event of this malfunction. Approvals of luminaires according to the old version of EN 60598 are being withdrawn by the testing institutes. The luminaires are tested using an equivalent circuit, whereby the respective resistors must be dimensioned to suit.

Electronic ballasts for HI and C-HI lamps

Electronic ballasts are fitted with all the components required to operate discharge lamps. Furthermore, they safely shut down lamps at the end of their service life to prevent high temperatures from being generated within the luminaires that could influence the service life of the luminaires and components. Vossloh-Schwabe provides electronic ballasts that are equipped with an additional switching contact that makes it possible, for instance, to switch on a light bulb during the dark phase of a discharge lamp.

By adding a strain-relief module, these electronic built-in ballasts turn into independent operating devices that can, for instance, be used as a power unit and can also be installed in intermediate ceilings in this form.

Components for discharge lamps

If the electrical current through a discharge lamp is increased, a discharge channel with very high luminous efficiency is created in the discharge chamber; luminous flux and light output increase substantially. The internal pressure of the discharge chamber rises and attains between 1and 10 bar these are so-called high-pressure discharge lamps (general: discharge lamp). The light output and colour rendition of high-pressure lamps vary considerably depending on the lamp family.
Discharge lamps can only be operated with ballasts. Ignitors are additionally required for sodium lamps and metal halide lamps. Furthermore, to compensate blind current when using magnetic ballasts, compensation capacitors must be fitted. The lampholders enable the lamp to be fixed in the luminaire and ensure simple exchange of lamps at the end of their service life. As well as stabilising the lamp´s operating point, ballasts also influence the lamp´s output and luminous flux, the system´s light output, the service life of the lamps as well as the colour temperature of the light

High-pressure sodium lamps (HS lamps)
Metal halide lamps (HI lamps)
Metal halide lamps with a ceramic discharge tube (C-HI lamps)
Mercury vapour lamps (HM lamps)
Low-pressure sodium lamps (LS lamps)
Ballasts can be of either electromagnetic or electronic construction. Unlike with fluorescent lamps, lamp efficiency is not decisively altered by the use of electronic ballasts. In contrast, electronic ballasts lead to a reduction of the inherent losses and thus to an increase in system efficiency. In addition, electronic ballasts ensure gentle lamp operation, which increases the lamp´s service life.

Fluorescent lamps

Fluorescent lamps are low pressure gas discharge lamps in which the invisible UV radiation generated by the discharge is converted into visible radiation (i.e. light) with the aid of phosphors. (Principle of fluorescence) There are tubular, ring-shaped and U-shaped fluorescent lamps and also compact fluorescent lamps. The tube diameter is often expressed in eighths of an inch (e.g. T5 = 5/8'' = 16 mm). In the lamp catalogues, diameters are also given in millimetres (e.g. 16 mm for T5 lamps). Most lamps are internationally standardized. Like all discharge lamps, fluorescent lamps cannot be operated directly on mains voltage because of their negative internal resistance characteristics. Suitable control gear between the mains supply and the lamp, limits and control the lamp current and ensures reliable starting under specific conditions. Fluorescent lamps have various operating modes, depending on the way in which the electrodes are brought up to the temperature:
Current-controlled preheating in switch-start mode, preferred in countries with a high mains voltage (200 V or more). Used in most electronic control gear (ECG).
Voltage-controlled preheating with additional transformer for "rapid start" mode.
No preheating (cold start, used for example with slimline lamps). This type of starting reduces the lamp life more than any other type and is therefore not recommended for systems with frequent on/off switching.
Electronic control gear (ECG) converts the mains frequency into a high frequency supply in the region of 35 to 50 kHz. As a result, the 100 Hz flicker that may appear as a stroboscopic effect, for example with rotating machines, is much less noticeable or virtually eliminated. Another advantage of ECG operation is the additional energy savings of around 25% for the same luminous flux, comprising:
10% high luminous efficacy from the fluorescent lamp operating at a high frequency
Much lower losses in the ECG (less than half) compared with conventional control gear (CCG) Dimming Dimmable ECGs make use of the property of a choke whereby its inductance increases as the frequency increases. As the operating frequency is made to increase, the choke connected in series with the lamp supplies a progressively lower current. The frequency is controlled via a 1-10 V or a DALI interface. The dimmable ECGs must also ensure that in the dimmed state the cathodes are constantly heated so that they continue to emit electrons even when the lamp current is at a low level. Lamp life and resistance to switching transients If fluorescent lamps are operated with CCGs and conventional starters their life is shortened considerably as the frequency of on/off switching increases. The same phenomenon can be observed with cold-start ECGs, which have the ability of starting fluorescent lamps instantly. However, the rapid transition from glow discharge temperature to emission temperature seriously damages the cathodes, so frequent switching cycles reduce the life of fluorescent lamps. Warm start control gear behave in a completely different way. In this case, the cathodes are heated before ignition, which virtually eliminates switching damage to the cathodes. The associated delay in ignition, of around a second is not a serious inconvenience. Thermal behaviour The physical properties of fluorescent lamps depend on their ambient temperature. This in turn depends on the characteristic temperature sensitivity of the mercury vapour pressure in the lamp. At low temperatures it is too low so there are too few atoms that can be excited. At excessively high temperatures the high vapour pressure results increasingly in self-absorption of the generated UV radiation. The lamps achieve their maximum luminous output at an ambient temperature of approx. 25°C. In the case of T5 lamps with a tube diameter of 16mm (FH®, FQ®) the rated luminous flux is specified at 25°C, as with other fluorescent lamps but their maximum luminous flux is achieved at an ambient temperature of 33°C to 37°C. In other words, one advantage of T5 lamps is the higher light output from ‘hot’ compact luminaires.

product of illuminance and time

Unit of measurement: lux second [lx s]Exposure H is defined as the product of illuminance and time (at constant illuminance).H = E * t E = illuminance (in lx)t = time (in seconds)Exposure meters are used in photography to determine the ideal exposure time for a given illuminance. Exposure is also an important factor in assessing safe display times for light-sensitive exhibits in museums.

Energy Label

According to EU Directive 92/75/EEC, household lamps operated on main voltage (incandescent lamps and fluorescent lamps with integrated control gear) and household fluorescent lamps (including single and double-ended lamps without integrated control gear) must be marked on their packaging with an energy label indicating their energy efficiency.The light sources are classified in energy efficiency classes A (very efficient) to G (inefficient).

Emergency lighting

There are two types of emergency lighting - standby lighting and safety lighting. Standby lighting takes over the functions of the normal lighting system if the power supply to that system fails so that essential work can continue. In most cases, standby power generators are used and these then supply power to the normal luminaires. The generators must guarantee at least 10% of the illuminance recommended for the activity. There are three types of safety lighting:
Safety lighting for escape routes; safe evacuation calls for a minimum illuminance of >1 lx at a height of 0.2 m, with a uniformity ratio of 1:40.
Escape lighting as minimum background lighting to enable people to reach emergency exits in large rooms.
Safety lighting for hazardous workplaces (near machines with moving parts) if failure of the normal lighting system presents an immediate risk of an accident or injury.

Disposal of old lamps

Disposal of old lamps and electronic control gear
Disposal of incandescent lampsIncandescent lamps consist of glass and metal. They do not contain any materials that will harm the environment so they can be simply thrown away with the household refuse. They should not be placed in containers for recycled glass, however, because the glass used for these lamps is not the same as the glass used for bottles. Tungsten-halogen lamps contain very small quantities of halogens and halogen-hydrogen compounds, but the amounts are insignificant (only a few millionths of a gram). Even several lamps together do not present any risk to people or the environment. The lamps can therefore be thrown away with household waste.Disposal of discharge lampsFluorescent tubes, compact fluorescent lamps, high pressure mercury, sodium and metal halide lamps all contain small quantities of mercury.These lamps can be recycled and the mercury recovered, but they can also be disposed of to special land-fill sites for mercury containing waste (seek advice from the Environment department of the local authority)Electronic control gearECGs do not contain any material that will harm the environment but they do contain recycable electronic components so they should be disposed of as electronic waste.

Dimming lighting system

Dimmable lighting systems were developed originally to meet the need for lighting that was easier on the eye. To an increasing extent, these systems are now also being used for cost saving reasons. Users can control the lighting with remote controls and switches, or control circuits with daylight sensors can be used. Leading edge phase dimming is used for low voltage tungsten halogen lamps operated with magnetic transformers. Trailing edge phase dimming is generally used for those lamps operated with electronic transformers. Compact fluorescent lamps (dimming range 3% to 100%) and fluorescent tubes (dimming range 1% to 100%) with electronic control gear are dimmed via a 1-10 V interface. Cables can either be laid separately (recommended for cable lengths > 100 m) or together, provided the requirements of wiring regulations are met.

DALI (Digital Adressable Lighting Interface)

DALI is a method of controlling electronic control gear for fluorescent lamps using digital signals. Unlike analogue brightness controls, DALI enables each luminaire to be controlled individually. It can be easily integrated in a building management system. Individual addressing means that not only the luminaires can be controlled but they can provide feedback messages so they can be operated in versatile energy-saving arrangements. DALI supplements Appendix E of the existing IEC Standard 929 in terms of the mode of operation of electronic control gear
1. Digital switching - Luminaires can be switched via the control cables irrespective of polarity.
2. Addressing - 64 ballasts can be addressed, allowing them to be controlled independently with a common control wire.
3. Simple control wiring - Switching and dimming circuits are independent of the wiring layout, allowing maximum flexibility and convenience; this low-voltage wire can be routed in any way and is polarity-free to reduce installation errors.
4. Refurbishment - Control circuits are independent of polarity. This allows the use of existing wiring in old buildings. In new buildings, a five-conductor cable for both power supply and control wiring can be employed.
5. Lighting scenes - Preset lighting scenes for different tasks and moods can be programmed and stored in the DALI ballasts.
6. Flexible room layout - Future layout changes do not necessitate wiring changes.
7. Upgrading - New sensors or interfaces can be added without changing the luminaire wiring; simply choose which luminaires are to be controlled and reprogrammed.
8. Distortion-free - Digital signals allow greater freedom in wiring layout.
9. Flexible - Each sensor can be configured to control any luminaire or group of luminaires.
10. Overlapping groups - Luminaires can be included in more than one sensor group, e.g. movement detection and infrared control.
11. 11 Infrared control zone 1 - Zones can be altered without the need to rewire.
12. Infrared control zone 2
13 PIR (passive infrared) controlled zone
14. Daylight regulating zone - Controlled by Photocell
15. DALI room controller

Control gear for fluorescent lamps

Discharge lamps have to be operated with control gear to limit the current. There is a choice of conventional, low-loss or electronic control gear. An important factor as far as quality is concerned is their power loss which, together with the lamp wattage, is used to calculate the system wattage.Electronic control gear (ECG) In contrast to conventional control gear, ECGs operate at frequencies at or above 30 kHz which means they offer significant gains in efficiency. These gains are based essentially on two mechanisms:
A reduction in electrode losses.
An increase in luminous efficacy, which is due almost entirely to more efficient conversion of electrical energy into the UV lines of the mercury atom at 185 nm and 254 nm.The use of modern ECGs, above all for fluorescent lamps, has led to significant increases in lighting comfort, economy and reliability.
Lighting comfort
Flicker-free starting
Pleasant flicker-free light with no stroboscopic effects
Silent operation with no annoying hum from chokes
No flashing of faulty lamps
Automatic restart of replacement lamps
Economy
Up to 30% savings in power input compared with CCG operation
More than 50% longer lamp life compared with CCG/LLG thanks to preheat start
Low maintenance costs
Suitable for use in emergency lighting systems to VDE 0108
Reduction in energy costs for air-conditioning systems
Reliability
Safe shutdown of defective lamps
Compliance with the specific standards for safety and EMC
Protective circuit to guard against transient voltage surges and prolonged overvoltages
Dimmable electronic control gear enables compact fluorescent lamps to be dimmed smoothly and without flicker from 100% to 3% luminous flux and tubular fluorescent lamps from 100 % to 1% luminous flux. Control is via a separate 1-10 V interface or a digital addressable lighting interface (DALI).
Conventional control gear (CCG):
This is a simple self-inductance comprising an iron core around which copper wire is wound. Because of its ohmic resistance there is considerable power losses and from self heating. The system wattage for a 26W compact fluorescent lamp operated with conventional control gear is 32 W; in other words, the power loss is 6 W (23%). By contrast, the system wattage with an ECG is 28 W, which corresponds to a power loss of only 7.5%. The various operating modes are as follows:
Switch-start operation
Starter less operation
Control gear with temperature limitation
Switch-start operation can be described as follows:
The voltage needed for the starter to generate a glow discharge between the bimetallic contacts, is lower than the ignition voltage of the lamp with cold cathodes. When mains voltage is applied, the starter generates a glow discharge, the current of which heats up the cathodes. The bimetallic contacts then close and the full short-circuit current of the choke flows through the cathodes of the lamp. As the bimetallic contacts cool down they spring open again. A high voltage pulse is generated by the choke to ignite the lamp. Once the lamp has ignited only the lamp voltage is across the starter. This voltage is too low to cause the starter to initiate a glow discharge, so does not attempt to light the lamp.Special lamps are needed for starter-less operation. Whereas fluorescent lamps connected to a European 230-240 V mains can be operated with simple chokes and an additional preheating transformer or a sophisticated double resonance choke is needed for starter-less operation. The voltage for lamps connected to American 120 V supply systems has to be transformed with two additional heater windings on the control transformer, which involves little extra outlay. For this reason, starter-less circuits are widespread in the USA. Control gear with temperature limitation help ensure that dangerous overheating does not occur as lamps reach the end of their lives. This protection is provided by thermal cut-outs approved in VDE 0712 T10 The European Ballast Directive (2000/55/EC) has classified all fluorescent ballasts in terms of their energy efficiency. The most inefficient types will be legally banned from sale in Europe from May 2002. The aim of the Directive is to encourage the widespread use of electronic control gear which are the best in terms of energy efficiency. Low-loss gear (LLG): Compared to conventional control gear, low-loss gear has a lower power loss but are larger and are more costly to manufacture because of their improved design and larger iron cores. The system wattage for a 26 W compact fluorescent lamp, for example, is around 30 W

Constant light control

This is incorporated into dimmable lighting installations with the aim of reducing lighting costs, increasing lighting comfort and promoting individuality.This form of control is based on a dimmable ECG with a 1-10 V interface or DALI in combination with appropriate sensors. A distinction is made between automatic controllers, manual controllers and complex controllers. The choice of appropriate 1-10V dimmer components depends to a large extent on the application.The lighting system is controlled by light sensors according to the amount of available daylight, so full use is made of free natural sunlight. Energy savings of up to 60% are possible, rising to 70% if motion detectors, time switches and sensors with automatic disconnection circuits are used.

Computer workstations

Guidelines for lighting at computer workstations are given in DIN 5035, Part 2 and EU Directive 90/270/EWG. Its appendix contains the following minimum requirements:Lighting
General lighting and/or special lighting (task lamps) must be dimensioned and arranged so that lighting conditions are satisfactory and contrast between the screen and its surroundings is adequate, according to the type of activity and the viewing requirements of the user.
Glare, reflex or reflections on the screen or any reflective surface must be avoided by arranging the objects in the work area according to the arrangement and technical properties of the artificial light sources. Reflex and glare
Computer workstations must be set up so that light sources such as windows, other openings, transparent or translucent partitions, bright items of furniture and light coloured walls do not produce reflections on the screen.
Windows have to be equipped with suitable adjustable mechanisms for preventing or reducing the amount of daylight falling on the workplace. For further technical information see the DIN 5035-7 and DIN 66234-7 standards.

Common Lamp bases (Conforming to IEC 60061)

Bases for GLS lamps(Dimensions in mm)

Bases for tungsten-halogen lamps(Dimensions in mm)

Bases for compact fluorescent lamps (for switch-start operation)(Dimensions in mm)


Bases for compact fluorescent lamps (for high frequency operation)(Dimensions in mm)


Bases for compact fluorescent lamps (for high frequency operation)(Dimensions in mm)




Bases for tubular fluorescent lamps(Dimensions in mm)

Bases for discharge lamps(Dimensions in mm)

Colour rendering

Depending on the location and the purpose, artificial light should enable colours to be perceived correctly as though being seen by natural daylight. Such assessments are based on the colour rendering properties of a light source, which are expressed in terms of the "general colour rendering index" Ra. The colour rendering index is a measure of the comparison between the chromaticity of an object under the light source being measured and its chromaticity under a reference light source.


Colour rendering property
Colour rendering group
Colour rendering index Ra
Typical lamp
Excellent
1 A
90
Tungsten halogen lamps, LUMILUX DE LUXE fluorescent lampsHQI.../D
Very good
1 B
80 - 89
LUMILUX fluorescent lamps HQI.../NDL or WDL
Good
2 A
70 - 79
Basic fluorescent lamps (25)
Satisfactory
2 B
60 - 69
Basic fluorescent lamps (20,23,30)
Fair
3
40 - 59
HQL
Poor
4
39
High-pressure and low-pressure sodium discharge lamps
The chromaticity of eight (or 14) test colours standardized in DIN 6169 that occur when they are illuminated by the light source being tested are compared with the same test colour when illuminated by the reference light source. The smaller the difference the better the colour rendering property of the lamp being tested. A light source with an Ra value of 100 shows all the colours perfectly, as in the case of the reference light source. The lower the Ra value, the worse the colour rendering.

Test colours for Ra8
R1
Old rose

R5
Turquoise

R2
Mustard yellow

R6
Sky blue

R3
Yellow-green

R7
Violet

R4
Light green

R8
Lilac

Additional test colours with saturated colours (Ra14)
R9
Red

R12
Blue

R10
Yellow

R13
Skin tone

R11
Green

R14
Leaf green

Characteristics of materials

When light hits material, such as a window pane, there are three different phenomena that come into play. Some of the light is reflected, some is absorbed by the material and the rest is transmitted. The resultant luminous flux components are known as Fr (reflected luminous flux), Fa (absorbed luminous flux) and Ft (transmitted luminous flux).The quantitative relationship between these parameters is as follows:
degree of reflectance r= Fr / F
degree of absorption a= Fa / F
degree of transmittance t= Ft / F (where r a t = 1 and Fr Fa Ft = F)
The luminous flux absorbed by material is converted into heat, which increases its temperature. The darker the material, the more luminous flux is absorbed. A single glass sheet with a thickness of 4 mm, for example, reflects 8% of the luminous flux that falls on it, 90% is transmitted and 2% is absorbed.The diagram below shows the extreme forms, namely fully directed and fully dispersed reflectance and transmittance.

Reflectance and transmittance

Burning position

The burning position defines the position in which lamps may or may not be operated. A combination of a letter and a number is used in which the letter indicates the datum alignment and the number is the half-angle of the recommended range. There are three basic datum positions: h = vertical, base ups = vertical, base downp = horizontal

Schematic diagram for burning positions

Luminance L

Unit of measurement: candela per square metre [cd/m2]1 [cd/m2] = 0,0001 cd/cm2 Luminance L is measured brightness of a light source or an illuminated surface. The eye is very good at distinguishing between different luminance values:

Light source
Average luminance [cd/m2]
Light source
Average luminance [cd/m2]
Xenon short-arc lamp
200 000 - 5000 000 000
Candle
7 500
Sun
1 600 000 000
Blue sky
5 000
Metal halide lamp
10 000 000 - 60 000 000
Specular louvred luminaire
100
Incandescent lamp
2 000 000 -26 000 000
Preferred values for indoor lighting
50 - 500
Compact fluorescent lamp
20 000 -70 000
White paper at 500 lx
100
Fluorescent lamp
5 000 - 30 000
White paper at 5 lx
1
Sunlit clouds
10 000

Luminous intensity I

Amount of light Q Unit of measurement: kilolumens per hour [klm/h].The amount of light is the luminous flux emitted by a light source over time.

Luminous intensity I
Unit of measurement: candela [cd].A light source generally emits its luminous flux F in different directions. Luminous intensity is the luminous flux emitted through unit solid angle (1 Steradian) in a particular direction.

The spatial distribution of the luminous intensity of a light source produces a three-dimensional luminous intensity distribution graph. A section through this graph produces the luminous intensity distribution curve for the relevant plane. It is usual to use the polar coordinates or the Cartesian coordinates and normalize the values to a luminous flux of 1000 lm for luminaires so the figures can be more easily compared.

Adaptation of Light

This is the ability of the eye to adjust to changes in luminance by making the pupil larger or smaller. It means we can see correctly across a wide range of illuminance values. The time taken to adapt in this way is largely determined by the luminances at the start and end of the adaptation process. This adaptation takes place very quickly from dark to light (brightness adaptation) but much more slowly (30 minutes or more) from light to dark (darkness adaptation).

Absorption

This is property of material to convert the radiation they receive (such as light) into different forms of energy, mostly heat. A measure of this property is the degree of absorption a = Fa / F, the ratio of the luminous flux absorbed to the incident luminous flux. (Reflection, Transmittance). a = Fa / F F = incident luminous fluxFa = absorbed luminous fluxFr = reflected luminous fluxFt = transmitted luminous flux


Reflection, Absorption and Transmission in schematic format

lamp designations

TC-S
Tube Compact-Single
TC-SEL
Tube Compact-Single Electronic
TC-D
Tube Compact-Double
TC-DEL
Tube Compact-Double Electronic
TC-T
Tube Compact-Triple
TC-TEL
Tube Compact-Triple Electronic
TC-Q
Tube Compact-Quad
TC-QEL
Tube Compact-Quad Electronic
TC-DD
Tube Compact-Double D-Shape
TC-L
Tube Compact-Long
TC-F
Tube Compact-Flat
T2 (T7)
Tube Ø 2/8" (7 mm)
T5 (T16)
Tube Ø 5/8" (16 mm)
T8 (T26)
Tube Ø 8/8" (26 mm)
T12 (T38)
Tube Ø 12/8" (38 mm)
T-U
Tube U-Shape
T-R
Tube Ring-Shape
T-R5 (T-R16)
Tube Ring-Shape Ø 5/8" (16 mm)

Explanation of the IP numbers

Explanation of the IP numbers for the degree of protection in accordance with DIN IEC 598/VDE 0711
Number
1st number

Brief description
Brief explanation of which foreign bodies must not be allowed to penetrate into the casing
2nd number

Brief description
Details on the protection to be provided by the casing
IP20
1st number
2
Protected from solid foreign bodies
Fingers and the like up to 80 mm long. Foreign bodies greater than 12 mm dia.
2nd number
0
Unprotected
No special protection.
IP...1
2nd number
1
Protected from water droplets
Water droplets (droplets falling vertically) do not cause any damage.
IP...3
2nd number
3
Protected from water splashes
Water spray from an angle of up to 60° from the vertical must not cause any damage.
IP...4
2nd number
4
Protected from water splashes
Water splashes from any direction must not cause any damage.
IP...5
2nd number
5
Protected from water jets
Water jets from any direction must not cause any damage.
IP...7
2nd number
7
Watertight (immersible)
No water in dangerous quantities may penetrate when immersed in water in the given conditions in terms of pressure and time.
IP...8
2nd number
8
Tight to pressurized water (under water)
The equipment is suitable for continuous operation under water in the conditions stated by the manufacturer.
IP4...
1st number
4
Protection from foreign bodies greater than 1 mm
Wires or strips thicker than 1 mm. Foreign bodies greater than 1 mm dia.
IP5...
1st number
5
Dust-protected
Dust penetration is not completely prevented but dust does not penetrate in quantities which inhibit proper operation.
IP6...
1st number
6
Dust-tight
No dust penetration.

EEI classification

The comparability of the input power drawn by fluorescent lamp circuits rests on the CENELEC standard.
In the majority of cases energy generation goes hand in hand with producing the socalled greenhouse gas CO2 as a by product. However, at the climate protection conferences in Rio, Kyoto, The Hague and Bonn, the European states agreed to reduce CO2 emissions.
Against this background, the EU commissioned the Comité Européen de Normalisation Electrotechnique (CENELEC) with elaborating a European standard for measuring the total input power of fluorescent lamp circuits (ballast lamp).
After being produced by the Technical Board "CENELEC TC 34 Z (Luminaires and Accessories)", the "Measurement Method of Total Input Power of Ballast Lamp Circuits" (EN 50 294:1998) came into effect on 01.06.1999.
The resulting comparability of the input power made it possible to draw up assessment criteria for identifying ecologically compatible ballasts.

Against the background of international requirements to reduce greenhouse gases (world climate protection conference), European Directive 2000/55/EC governs the use of ballasts for fluorescent lamps. The new directive regarding energy efficiency requirements prohibited the sale of energy-class D ballasts on the European market (EU) with effect from 21.05.2002 and will prohibit the sale of energy-class C ballasts .

Lampholders for compact fluorescent lamps

Vossloh-Schwabe produces the majority of lampholders for TC lamps using PBT, a thermoplastic material. This highly heat-resistant material is responsible for the T140 temperature rating. Leading lamp manufacturers also use PBT for the lamp bases they produce. This material harmonisation in conjunction with fatigue-free, stainless steel lamp mounting springs ensures a permanently secure lamp fit.
Lampholders for double-ended fluorescent lamps
VS lampholders for T lamps are characterised by a number of technical features that guarantee a high degree of reliability and safety. In the first instance, the large rotor, which is characteristic of the vast majority of these lampholders, acts as a heat shield. Made of extremely heat-resistant PBT, the rotor´s fatigue strength at elevated temperatures amounts to 140 °C. Thus shielded against the heat of the lamp base, these lampholders attract a temperature rating of T130. In addition, Vossloh-Schwabe produces another series of rotor-like push-through lampholders whose complete front plate is made of PBT and thus acts as a heat shield. These lampholders attract a temperature rating of T140.
The maximum permissible temperature at the lampholder rear of Tm 110 °C is applicable to all lampholder types. The second key feature of these lampholders is a highly effective lamp pin support that reliably prevents base pin deflection even on older lamps and guarantees a durable and firm contact.




Push-through lampholders
Push-through lampholders are inserted from below through a cut-out in the luminaire casing and are secured by lateral catches. This type of lampholder is frequently used in luminaires on which the lampholder remains visible from the outside, e.g. in so-called strip lighting. The electrical leads are laid beneath the sheet metal level. With push-through lampholders, the starter essentially determines the dimensions of the luminaire because it has to remain accessible from the outside and is thus positioned vertically in front of the lampholder.


Push-fit lampholders
This lampholder type, which is frequently found in surface-mounted ceiling and built-in luminaires, is pushed into the luminaire casing from above. The lampholder foot should protrude by no more than 4 mm to match the usual height of the spacing cams in the luminaire casing. These lampholders are mostly wired above the luminaire casing to the side of the lampholder. However, there are also lampholders on which the wiring runs through the lampholder foot, with the leads laid beneath the luminaire casing.







Built-in lampholders
This design is also predominantly used for recessed ceiling and surface-mounted luminaires. However, unlike push-fit lampholders, built-in lampholders are usually fitted at the ends of the luminaire boxes. In addition to the usual fixing with split pins attached to the rear, there are also countless versions with fixing clips, push-fit studs or screw-in holes, which are also available with spring-loaded length compensation. Built-in lampholders offer luminaire designers a wealth of scope regarding the choice of lamp position in relation to the reflector. This enables great variation in light distribution as the lampholder does not dictate the distance of the centre of the lamp from the metal casing.


Surface-mounting lampholders
The fastening system of surface-mounting lampholders usually consists of screws or rivets above a fixing level, along which the wiring is also laid. As this type of installation is usually too costly nowadays for large unit numbers, these lampholders are used almost exclusively for special applications, e.g. displays or illuminated advertisements.

Connecting terminals

In the interest of ensuring firm contacts and long component service life, Vossloh-Schwabe uses only top-quality materials for plastic or metal parts during the production of connection terminals. These quality features apply to both Vossloh-Schwabe´s luminaire connection terminals as well as to the terminals fitted to ballasts and lampholders.
Notes on connection terminals on electronic ballasts
Vossloh-Schwabe electronic ballasts are fitted with installation-friendly push-in connectors. In addition, many models for linear fluorescent lamps are also available with IDC terminals (for solid conductors, 0.5 mm²) and supplementary push-in terminals (for solid conductors, 0.5 -1.5 mm², stripped length 8+1mm or 7.5 - 8.5 mm). IDC terminals permit automated luminaire wiring and testing using the ALF system and are thus particularly efficient.
Notes on connection terminals on electromagnetic ballasts
Standard issue Vossloh-Schwabe electromagnetic ballasts are fitted with installation-friendly IDC/push-in terminals (combination terminals) or push-in terminals. The terminals are designed for use with solid conductors with cross-sections of 0.5 -1.0 mm² (combination terminals) or up to 1.5 mm² (push-in terminals) and are approved for current loads of up to 3 A (combination terminal) and 16 A (push-in terminal). The lead stripping length totals 8±1mm for push-in terminals; leads must not be stripped for IDC terminals.
On request, many ballasts can also be provided with screw terminals (current load up to 16 A) for conductor cross-sections of 0.5 to 2.5 mm².
Notes on connection terminals on lampholders
Vossloh-Schwabe usually equips lampholders for T and TC lamps as well as starter lampholders with installation-friendly push-in terminals for solid conductors of 0.5 -1.0 mm². Most lampholders are fitted with twin push-in terminals and thus permit through-wiring. The required lead stripping length amounts to 8+1mm for all types.





IDC terminals
In order to fully exploit the vast potential for rationalisation offered by automated wiring and testing with the ALF system, a totally new component family was developed that is equipped with the VDE-tested IDC terminal technology. This technology has already been used very successfully on a large scale in other branches of industry. This modification of the terminal geometry dispenses with the stripping of conductors that is required for the push-in, screw or crimping methods. This triedand-tested IDC terminal technology has created the foundation for efficient automation as it ensures high connection quality, rapid contacting as well as quality assurance. Components equipped in this fashion make it possible to through-wire several terminals with a single conductor. This constitutes a further economic advantage as it significantly reduces the required conductor lengths. Furthermore, this design principle makes it possible to use adapters to simply and reliably make electrical contact from above for a VDE-compatible final luminaire inspection.

Circuit diagrams for the operation of fluorescent lamps with electromagnetic ballasts




Inductive single circuit


Inductive tandem circuit





Parallel-compensated single circuit




Parallel-compensated tandem circuit







Parallel-compensated single circuit with high-reactance transformer




Parallel-compensated tandem circuit with high-reactance transformer

Electromagnetic ballasts

Electromagnetic (inductive) ballasts are active components that in conjunction with starters preheat the lamp electrodes, supply the ignition voltage and stabilise lamp currents during operation. Series or parallel capacitors are required to compensate blind current.
For installation in luminaires, consideration must be taken of the mains voltage and mains frequency, the dimensions and maximum thermal values as well as any potential noise generation. To fulfil these special requirements, Vossloh-Schwabe provides numerous ballasts with differing technical specifications.
Vossloh-Schwabe magnetic ballasts have been optimised with regard to their magnetic fields and loads so that they are usually unnoticeable. However, as magnetic vibrations can affect large areas depending on the luminaire design, this should be taken into consideration when designing luminaires. If necessary, beads or grooves should be fitted to prevent vibrations from spreading. The service life of an inductive ballast is determined by the material chosen for the winding insulation. The maximum winding temperature denotes the temperature (tw) that the insulation will withstand for a period of 10 years given continuous operation under rated conditions. This maximum winding temperature must not be exceeded in real conditions to ensure the ballast can achieve its full service life. The winding temperature of the ballast that is measured in the luminaire is made up of the ambient temperature of the luminaire, the thermal conditions within the luminaire and the power loss of the ballast. The Dt marking on the ballast type plate provides a measure of the power loss of the ballast. In addition to this, the power loss of ballast-lamp circuits is measured in accordance with EN 50294. This test method forms the basis for the CELMA energy classification of ballasts and is also applied in European Directive 2000/55/EC "Maximum Values Regulation of the Power Input of Fluorescent Lamp Circuits".

As a result of their design features, inductive ballasts cause leak current that is discharged via the earth conductor (potential connection) of the luminaire. The maximum permissible leak current for protection class luminaires is 1mA, a value of which all Vossloh-Schwabe electronic ballasts fall clearly short. Values of max. 0.1 mA are measured per electromagnetic ballast. However, as these values accumulate with the number of installed ballasts, this should be taken into account when dimensioning the F1 protective switch.
Starters for fluorescent lamps
As mentioned above, the operation of fluorescent lamps also requires starters in addition to ballasts. A distinction is made between glow starters, which are also available with automatic cut-outs, and electronic starters. The correct choice of voltage and power range is crucial. Starters are available for 220 - 240 V and for 110 -127 V mains voltage. The latter are also required for twin-lamp operation (e.g. 2x18 W at 230 V). Operating the VS ballast SL (100 -127 V) depends on the use of a 220 - 240 V starter as these operating devices are high-reactance transformers that supply higher voltages to the lamp.

Circuit diagrams for the operation of fluorescent lamps with electronic ballasts

Circuit diagrams for the operation of tubular fluorescent lamp




Circuit diagrams for the operation of compact fluorescent lamps

Electronic ballasts (EB)

Ballasts for fluorescent lamps
The operation of a fluorescent lamp depends on a ballast that stabilises the lamp´s preheat current after connection to the mains and, in conjunction with the starter, also supplies the required lamp ignition voltage after preheating. After lamp ignition, the ballast then serves to limit the lamp current. As fluorescent lamps are characterised by a negative characteristic current-voltage curve, lamp current stabilisation is extremely important with regard to both the lamp´s stable operation and its service life. In addition to this, a lamp´s service life is critically dependent on compliance with the starting conditions (preheat current and ignition voltage). Unfavourable starting conditions cause damage to the electrodes every time the lamp is started and thus reduce the lamp´s service life. Furthermore, care should be taken to prevent cross-discharge in the electrode area during preheating, which also shortens lamp service life.
Ballasts are available in electromagnetic or electronic form. Electromagnetic (inductive) ballasts have to be operated in conjunction with starters for lamp ignition and capacitors for blind current compensation. In addition, capacitors for RFI suppression will also be required for certain circuits. Electronic ballasts can be operated without any additional components.
Electronic ballasts (EB)
VS electronic ballasts are designed for mains voltages of 220 V to 240 V and are used to operate fluorescent lamps at high frequency (20 - 50 kHz). The lamps are ignited with an internally generated ignition voltage, thereby removing the need for an external starter. The power factor (l) > 0.95 also removes the need for compensation, unlike with electromagnetic ballasts. The only exceptions are low-output ELXs models, which attain a power factor of 0.6. Luminaires fitted with electronic ballasts are characterised by low energy consumption as they have substantially lower system power than conventional, inductive applications. This is firstly because the lamp consumes less power to achieve the same luminous flux and secondly the internal loss of an electronic ballast only amounts to approx. 8 % to 10 % of the lamp´s output. Furthermore, thanks to their modern circuitry, the power input of VS electronic ballasts remains constant even in the event of mains voltage fluctuations, thus ensuring permanently low energy consumption.
Vossloh-Schwabe electronic ballasts permit a broad range of applications. For instance, VosslohSchwabe´s product range includes many ballast types for multiple lamp operation. These ballasts reduce installation and component costs and thus enable particularly efficient luminaires. Twin-lamp electronic ballasts permit so-called master-slave operation. The lamps of two single-lamp luminaires are operated by a twin-lamp electronic ballast that is built into the so-called master luminaire. The lamp of the slave luminaire is electrically connected to the electronic ballast.
The use of electronic ballasts makes a lighting system both more convenient and efficient to operate:
reduced power consumption (up to 30 %) at undiminished light output
50 % longer service life
stabilised lamp output
overvoltage protection
no stroboscopic effect
flicker-free lamp start
no need for a starter or capacitor
low wiring effort
no radiated electromagnetic interference
low self-heating due to minimal power loss
automatic shutdown of defective lamps
automatic restart once the lamp has been changed
Vossloh-Schwabe electronic ballasts are developed on the basis of the latest technological and component standards and are produced using state-of-the-art technology, whereby consideration is taken of our customers´ quality standards in our quality assurance system.

Vossloh-Schwabe provides the respective electronic ballast family for the most diverse applications:
ELXs ballasts (warm start)
The family of ELXs ballasts forms a perfect alternative to magnetic ballasts. ELXs ballasts have the same fastening hole spacing as standard electromagnetic ballasts. The lamp is ignited after a preheating time (warm start) of 1.5 seconds. These ballasts are available for system outputs (lamp output plus power loss of the electronic ballast) of up to 25 W. The power factor of these ballasts amounts to approx. 0.6. The average service life of these ballasts totals 30,000 hours with a failure rate of ≤ 0.2 % per 1,000 operating hours.
ELXe ballasts (instant start)
With this ballast family, the lamps ignite immediately after connection to the mains voltage by applying an ignition voltage of max. 1,500 V to the gas discharge path of the lamp. The ignition time totals less than 0.2 seconds. As this puts a severe strain on the electrodes, the realistic number of lamp starts is limited to approx. 10,000 ignitions up to the end of the lamp¢¥s service life. For that reason, ELXe ballasts should only be used for applications demanding fewer than five lamp ignitions per day (e.g. in production sites, warehouses or department stores). As there is no need for preheating, ELXe ballasts only require one connection per electrode for lamp operation. This makes them suitable for use in explosion protected luminaires. In addition to this, they are extremely energy efficient as no lamp electrode losses occur. The average service life of these ballasts totals 50,000 hours with a failure rate of ≤ 0.2 % per 1,000 operating hours.
ELXc ballasts (warm start)
ELXc ballasts ensure the lamp is started following a defined lamp electrode preheating period of approx. 1.5 seconds using a fixed ignition voltage. This particularly gentle lamp start makes over 20,000 lamp starts possible. ELXc ballasts should be used for applications with high switching frequencies (e.g. hotels or offices) where energy savings as well as low maintenance costs are desired. The average service life of these ballasts totals 50,000 hours with a failure rate of ≤ 0.2 % per 1,000 operating hours.
ELXd ballasts (dimmable)
These are ELXc ballasts with an additional dimming function that is controlled via an interface fitted to the ballast. The interface of these ballasts can be either analogue (1-10 Volt) or digital (DALI; PUSH); the interface enables lighting to be ideally adjusted to suit the given need. Control components can also be used as long as they comply with the respective standard (appendix to IEC/EN 60929). When using ELXd ballasts in a lighting system, an energy saving of 75 % can be achieved if the control inputs of the ballasts are coupled with movement detectors and light sensors. The average service life of these ballasts totals 50,000 hours with a failure rate of ≤ 0.2 % per 1,000 operating hours.
To guarantee trouble-free operation and a long service life of the various types of electronic ballast, attention should be paid to the regulations and mounting instructions. In addition, the installation instructions for lighting systems must be observed when installing luminaires with electronic ballasts.

Bases for mains voltage incandescent lamps

The bases of the most widely used mains voltage incandescent lamps

Lampholders for mains voltage halogen lamps

A major factor in lampholder design is the lamp temperature, which is determined by the tungstenhalogen cycle, the high lamp current and the high wattages. Lampholder casings can be made of ceramics, metal or the ever more popular highly heat-resistant thermoplastics like PET (polyethyleneterephthalate), PPS (polyphenylene sulphide) and LCP (liquid crystal polymer). The most suitable contact materials for these temperatures are nickel, copper-nickel alloys or copper materials with sufficiently thick nickel coatings. For tubular lamps (R7s base), the standard IEC 60061-2 7005-53 prescribes the respective contact pressure of lampholder contact materials.

Although halogen lamps offer twice the service life of general-purpose light bulbs, this can only be fully realised if luminaire manufacturers observe the recommended maximum temperatures at the lamp´s pinch point. There is usually a welded-on molybdenum plate at the pinch point where the lamp base pins join the lamp filament. Lamp manufacturers as certain the pinch temperature at this point, which is generally within the lamp´s quartz glass, using specially prepared measuring lamps. The pinch temperature is a critical thermal reference point which must not be exceeded within the luminaire.

Bases for low-voltage halogen lamps

The bases of the most widely used low-voltage halogen lamps

Lampholders for low-voltage halogen lamps

With the exception of the B15d bases, the low-voltage sector is dominated by pin bases, which are fitted with a variety of different pin distances and diameters. Apart from classic lampholders that ensure both the electrical contact and the correct positioning of the lamp, connection elements are also available. These components are solely responsible for establishing electrical contact and are used in cases where, for instance, the regulations demand that the lamp be attached to its reflector (e.g. cold-light reflector lamps with GZ4 and GX5.3 bases). Extremely high temperatures are also generated during the operation of low-voltage halogen lamps as a result of the tungsten-halogen cycle and the high lamp currents. In addition, the respective luminaires are often of very compact design, which leads to heat accumulation and thus high internal temperatures. The materials the lampholder is made of thus play a vital role for the luminaire´s operating safety and the lamp´s service life. In addition to tried-and-tested materials - ceramics for casings and mica for covers - ever more frequent use is being made of highly heat-resistant plastics like LCP [liquid crystal polymer], (e.g. G4, GU4, GX5.3, GU5.3 and GY6.35 lampholders) and PPS [polyphenylenesulphide] (G4 lampholders). Plastic lampholders provide clear advantages: narrow tolerances, no material fractures, low weight and clip-attachment options.

The type of contact also plays an important role. Conventional contacts are only attached to one side of the lamp pin. In contrast, additional contact points - known as multipoint contacts - lead to a reduction of current density at the point of transition from the lamp pins to the lampholder contact and with that to a decrease in temperature. These contacts provide the further advantage of ensuring superior heat dissipation from the lamp pins to the conductor, where it can be radiated. The temperature advantage of multipoint contacts in defined conditions (including welded-on conductors) can amount to as much as 100 °C. In extremely rare cases, due to the high internal pressure in the bulb, it is possible for the lamp to shatter. For reasons of fire prevention (high temperature of the glass bulb), the lamp´s components must be prevented from falling out. Enclosed luminaires meet these requirements. Open luminaires, however, may only be operated using lamps with enclosed bulbs or low-pressure lamps. Lamps of this kind are suitably marked with pictograms on the lamp´s packaging and in the lamp manufacturer´s documentation. Lamps marked with pictogram no. 1 are suitable for use with open luminaires, whereas those marked with pictogram no. 2 may only be used in enclosed luminaires.
Lampholders for low-voltage halogen lamps are equipped with mounted cables or with plug-type connectors. In addition to the various lampholders contained in the catalogue, further lampholder models with various cable lengths and of various qualities as well as lampholders with plugconnected cables can be made available on request.

Conductors for low-voltage installations

As the high temperatures associated with the operation of low-voltage halogen lamps place severe demands on lamp holder conductors, a skilful combination of conductor and insulation is essential. Tin-plated copper conductors with silicone insulation are recommended for temperatures of up to 180 °C at the cable´s conductor; nickel-plated copper cables with polytetrafluoroethylene (PTFE) sheathing are recommended for temperatures of up to 250 °C. Welded connections ensure the most effective heat discharge. Control measurements should be carried out if other connection types are used, e.g. crimping or plug connectors. To prevent the risk of additional heat generation, the maximum permissible current load must be observed when dimensioning the conductor cross-section. When using electromagnetic transformers, the conductor resistance causes a relatively large voltage drop. This drop in voltage is always associated with a reduction of luminous flux. For instance, an 11 % drop in voltage will lead to a 30 % drop in luminous flux. For this reason, care should be taken to ensure secondary conductors are kept as short as possible and conductor cross-sections are adequately dimensioned when wiring luminaires. Nevertheless, transformers should not be mounted too near the light source (> 25 cm clearance if possible) to prevent the heat generated by the lamp from raising the ambient temperature above the critical level for a transformer.
As electronic converters operate at high frequencies, consideration must be taken of the skin effect, i.e. the displacement of the electrons from the middle of the conductor to its surface. As a result, the full cross-section of the conductor is no longer used, the resistance increases and the voltage drops. In addition, the alternating current resistance, which is caused by the inductance of the feed line, can result in an even greater voltage drop. It is therefore recommended that lamp conductors be laid closely parallel or twisted together.

Voltage losses (V) from a two-metre secondary conductor
Working frequency
Load W
Cross-section mm²
0,75
1
1,5
50 Hz ( electromagnetic transformers)
50
0,38
0,29
0,2
any wiring layout
100
0,74
0,56
0,39
40 kHz (electronic converters)
50
1,4
1,25
1,2
any wiring layout (loops)
100
3,3
3,1
3
40 kHz (electronic converters)
50
0,5
0,45
0,35
wires twisted together or closely parallel
100
1,2
1
0,85
Conductors for installations with halogen lamps
All conductors must be selected to suit the luminaire conditions (see table) in terms of material, cross-section and insulation. Testing these conductors under unfavourable conditions is essential as the commonly occurring high temperatures considerably reduce the conductivity of the conductor and hence its current-carrying capacity.
Insulation
Conductor
Cross-section
Mains voltage
Max. temperature
Material
mm²
V
°C
Si
Cu tin-plated
0,75
300
180
PTFE
Cu nickel-plated
0,75
500
250
PTFE
Cu nickel-plated
1
500
250
PTFE
Ni
1
500
250
PTFE
Ni
1,5
500
250

Dimmability of VS transformers and VS converters

Electromagnetic VS transformers can be controlled using phase-cutting leading-edge dimmers. These dimmers "cut" the sinusoidal mains voltage in the negative and positive half wave at an angle in the ascending portion of this sinusoidal half wave. The higher the angle is set at the dimmer controls, the lower the voltage and hence the lamp´s output.
Electronic VS converters can be controlled using phase-cutting trailing-edge dimmers. In this case, a semiconductor ensures the pre-defined descending portion of the sinusoidal half wave is clipped. VS converters of the LiteLine and TopLine series can be operated with either phase-cutting leading-edge or trailing-edge dimmers. Twin Line converters feature a separate potentiometer connection for adjusting lamp brightness.




Working principle of the phase-cutting leading-edge dimmer: Alpha=Ignition angle, I=Current, Lambda=Current flow, U=Voltage


Working principle of the phase-cutting trailing-edge dimmer

Electromagnetic transformers

Low-voltage halogen lamps operate at voltages of under 24 V. Owing to this low voltage, all Vossloh-Schwabe transformers are safety transformers. Safety transformers are isolation transformers for supplying SELV (safety extra low voltage) and PELV (protection extra low voltage) circuits. With such systems, the voltage must not exceed a value of 50 V AC or 120 V DC (smoot hed) between the conductors or a conductor and the earth conductor of a circuit that is separated from the mains by a safety transformer. The stated values apply for non-touchable parts only, for touchable parts values are 24 V AC and 34 V DC.
Owing to the low internal impedance of electromagnetic transformers, high currents can occur in the event of a short-circuit on the secondary side, which can lead to the transformer being destroyed. For this reason, IEC 61558-1 differentiates between three types of transformer:
Not short-circuit proof transformers
These transformers require external protection to prevent excessive temperatures being generated.
At Vossloh-Schwabe, these transformers are marked with the symbol "not short-circuit proof safety transformer". To protect against current overload during over load or short-circuit operation, Vossloh- Schwabe recommends installing a fuse on the primary side. As an aid to the user, the rating of this fuse is stated on the type plate in accordance with IEC 60127. The installed primary-side fuse should be easily accessible so that it can be readily replaced at any time.
Short-circuit proof transformers (limited short-circuit resistance)
These transformers feature a safety device that prevents excessive temperatures being generated.
Electromagnetic transformers with thermal cut-outs afford a limited degree of short-circuit resistance and do not need to be additionally fused. VS safety transformers of limited short-circuit resistance are designed to safely cut out in the event of overload or short-circuit, but not to restart automatically after cooling off. The transformer must first be disconnected from the mains (i.e. switched off and on) before it can be restarted. The thermal cut-outs are dimensioned to ensure that the maximum permissible winding temperature of 225 °C (transformers of thermal class B) or 240 °C (F) or 260 °C (H) is not exceeded in the event of overload or short-circuit.

Short-circuit proof transformers (unlimited short-circuit resistance)
These transformers are designed to ensure that fixed maximum temperatures are not exceeded in the event of overload or short-circuit.
This type of safety transformer is not in use within the lighting industry as it requires relatively large dimensions to meet the overload and short-circuit requirements.
All transformers will function perfectly and meet the requirements of the standard after the overload or short-circuit has been eliminated.
In addition to the above, there are also so-called fail-safe transformers that are rendered permanently in operative in the event of improper use, but do not pose a threat to the user or the surroundings. Vossloh-Schwabe does not provide this type of isolation transformer.
All Vossloh-Schwabe transformers are tested for compliance with the safety requirements of European standard EN 61558 regarding creepage and air clearance distances, the winding temperature and the maximum permissible ambient temperature (ta).
EN 61558 specifies five insulation classes for electromagnetic transformers; respective testing temperatures and times are assigned to this insulation system. Due to the quality of the insulation materials used by Vossloh-Schwabe, VS transformers are only available in the three highest insulation classes B (120 °C), F (140 °C) and H (165 °C). In this case, the quoted temperature refers to the maximum permissible winding temperature during permanent operation.
As luminaire casings made of plastic or sheet metal will discharge heat to varying degrees and because transformer installation conditions can differ, a transformer´s winding temperature must be tested within the luminaire. The measured values will show whether the maximum temperature complies with the transformer´s insulation class.
On request, Vossloh-Schwabe can carry out such luminaire tests to assess built-in components.

Electronic converters

The safe operation of electronic converters is dependent on the maximum permissible temperature not being exceeded at the measuring point. Vossloh-Schwabe has determined a casing temperature measuring point - tc max. - on all converter casings. To avoid shortening the service life of these devices, the stipulated maximum temperature must not be exceeded at this tc point under any circumstances. This point is determined by testing the converter during normal operation in an IEC-standardised box at the specified ambient temperature (ta), which is also indicated on the typeplate. As both the design-related ambient temperature and the converter´s own heat generation as determined by the installed load are subject to great variation, lamp manufacturers should test the casing temperature at the converter´s tc point under real installation conditions. Temperature-protected converters feature a further protection symbol, a triangle containing the maximum temperature. This symbol certifies that the respective device is equipped with additional protection against overheating and specifies that the surface temperature of the casing must not exceed the value stated within the triangle under any circumstances.

Vossloh-Schwabe electronic converters are tested in accordance with EN 61347. Function tests are carried out in accordance with EN 61047. VS converters can be operated without causing any inadmissible system reactions, as all devices comply with EN 61000-3-2 on the limitation of mains harmonics. They also meet the EMC requirements of EN 61547; these devices are thus also protected against mains surges that can be caused by, for instance, inductive ballasts during combined operation of fluorescent and low-voltage halogen lamps. In addition, all devices comply with the RFI requirements of EN 55015. As the highly effective integrated filter can only limit the unit´s own interference, the secondary conductor should be kept to under 2 metres in length so as to avoid RFI interference in the lighting system.

Transformers and converters for low-voltage halogen lamps

Operating low-voltage halogen lamps depends on operating devices that transform the usual mains voltage of 230 V to approx. 11.5 V. Safety transformers, of either electromagnetic or electronic (converter) design, have been in almost exclusive use for several years now. The type plate of electromagnetic transformers bears the symbol for safety transformers in accordance with VDE 0570, corresponding to EN 61558. Electronic converters are marked with the sign for Safety Extra Low Voltage (SELV), which indicates that the product is an isolating converter whose secondary out put is safe to touch even during no-load operation.
Transformers and converters fall into one of two protection classes. Operating devices of protection class I are base-insulated and must always be connected to a protective conductor. Isolating transformers and converters of protection class II are equipped with double or reinforced insulation that protects against dangerous casing currents.

Operating devices can also be differentiated according to the way they are used. Built-in transformers have to be installed in a permanent casing, e.g. aluminaire. In contrast, so-called independent transformers and converters can be operated independently of a luminaire. These are often found in ceiling installations; in order to prevent possible noise development, isolation transformers must be mounted in such a way as to avoid vibration transmission.
Transformers or converters bearing the MM mark can be mounted on surfaces of unknown flammability, which can be the case when mounting these devices on wooden furniture elements. Such devices comply with the temperature requirements of VDE 0710, part 14, of < 95 °C during normal and < 115 °C during abnormal operation

Temperature limits for plastics

Abbreviation
Name
Max. permissible temperature according to IEC 60598-1 (°C)
FS 181
Melamine, rock dust
100
PE
Polyethylene
80*
PP
Polypropylene
100
PA
Polyamide
120
PA GF
Polyamide, glass fibre reinforced
190*
PC
Polycarbonate
130
PBT GF
Polybuteneterphthalate, glass fibre reinforced
210*
PET GF
Polyethyleneterephthalate, glass fibre reinforced
240*
PPS
Polyphenylene sulphide
260*
LCP GF
Liquid crystal polymer, glass fibre reinforced
280*/300** according to manufacturer specifications

Protection classes of luminaires and operating devices

The degree of insulation against electrical shock offered by luminaires and operating devices is split into two safety levels. These two safety barriers are designed to prevent any risk to safety in the event of a defective device.Luminaires and operating devices of protection class I provide protection against electrical shock solely using the base insulation and the safe connection of all exposed conductive parts to an earth conductor. Thus, should the base insulation fail, no exposed conductive parts can become live.Luminaires and operating devices of protection class II provide protection against electrical shock using both the base insulation and an additional or reinforced insulation. Protection class II products do not feature a connection to a protective earth conductor. (In special cases a device can feature or be required to feature a functional earth, e.g. for EMC reasons, or a continuation of the protective earth conductor in a luminaire.) The mounting conditions do not ensure any additional degree of protection, either.However, the connection of a protective earth conductor can also be permitted for protection class II luminaires in the following cases:
for EMC reasons – in such cases, it can be necessary to connect a function protection conductor to remain within EMC limiting values. The component manufacturer´s specifications regarding the individual operating devices must be observed during the construction of the luminaire. If an operating device is marked as containing a function protection conductor, the creepage and air clearance distances of the operating device connection must comply with the requirements of protection class II;
as an ignition aid for lamps – connecting a function protection conductor can be necessary as a capacitive ignition aid for lamps. In such cases the creepage and air clearance distances around the ignition aid within the luminaire and the function protection conductor connection terminal have to comply with the requirements of protection class II. The ignition behaviour of a lamp should be agreed with the manufacturer in these cases;
when wiring the protective conductor from the luminaire to another device. This installation point must comply with the creepage and air clearance distances stipulated in the luminaire standard.

Operating devices with double or reinforced insulation for installation in protection class II luminaires
Protection class II specifications have to be met by the luminaire along with its installed operating device. Both protection class I and class II ballasts can be installed. The design of the luminaire must be adapted to suit. This means that if a protection class I ballast is installed in a protection class II luminaire, the design of the luminaire has to be correspondingly sophisticated to ensure the creepage and air clearance distances can be met. On the other hand, using a protection class II ballast, only available as an independent ballast nowadays, will in most cases result in a need for too much technical effort and thus in high costs. Against this background, the standards contain special requirements for ballasts destined for installation in protection class II luminaires.These "double or reinforced insulation ballasts" permit technically and cost-effective construction of protection class II luminaires.
Protection class III luminaires provide protection against electrical shock by using Safety Extra Low Voltage (SELV). Luminaires of protection class III are not permitted to generate higher voltages than the Safety Extra Low Voltage (SELV).