D7BCT datasheet(39/54 Pages) OSRAM

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OSRAM DULUX® EL – electronic energy saving lamps

Economical alternatives to ordinary light bulbs

Technical Guide

3.5.3 Dimmer operation

3.5.4 Operation on

electronic switches

Brightness control with standard dimmers is not possible with OSRAM DULUX® EL

lamps.

The electronic control gear of the lamp contains a rectifier and smoothing capacitor

(electrolytic capacitor) in the input circuit. This electrolytic capacitor is always charged

to the peak value of the AC voltage; mains current flows only briefly and up to the

maximum mains voltage.

This design prohibits operation with standard dimmers since leading-edge and

trailing-edge dimmers would damage the electrolytic capacitor with their steep

voltage rises and associated high peak currents.

In addition, most dimmers require a minimum load of many times that of an OSRAM

DULUX® EL lamp so that even with the dimmer fully turned up, its switching element

would not find an adequate holding current, with the result that the lamp would be

continually switched on and off. This would not only damage the OSRAM DULUX® EL

lamp, it may also destroy the dimmer.

As an alternative to external dimmer systems, OSRAM therefore offers the OSRAM

DULUX® EL VARIO, the lamp with integrated two-stage brightness control (cf. 1.3.10).

This mode of operation is possible only if certain conditions are met.

Because of the design of the input circuit, current flows only for about 4 ms per mains

half-wave (cf. 3.5.3). The peak value of this current is three times the rms value. This

high crest factor must be taken into account when operating the lamp with electronic

switches. Simple thyristor or triac switches that are triggered only once after zero

crossing are not suitable because the OSRAM DULUX® EL does not draw holding

current at this point. An ohmic load (such as an incandescent lamp) would have to be

operated in parallel with the OSRAM DULUX® EL. This would then ensure the holding

current for the electronic switch.

More suitable are electronic switches that do not need a holding current (for example

those with a MOSFET as the active switching element), or a relay and contactor.

Note the maximum switch-on current of 25 A for approx 80

µs half-value width

(except VARIO: 48 A). A reduction to less than 1 A per OSRAM DULUX® EL is

possible if, with appropriate control of the electronic switch, the lamp is only

switched on at zero crossing.

The maximum charge taken up in the switch-on current surge is between 0.4 and

3 mAs (depending on the wattage); the maximum energy taken from the source per

switch-on current surge is 1 Ws (2 Ws if switch-on takes place at maximum mains

value). This applies to OSRAM DULUX® EL LONGLIFE, OSRAM DULUX® EL

ECONOMY, OSRAM DULUX® EL FACILITY, OSRAM DULUX® EL SENSOR Plus and

OSRAM DULUX® EL VARIO.

3. Lamp data and lamp properties

D7BCT Datasheet(PDF) 39 Page - OSRAM GmbH

D7BCT Datasheet(HTML) 39 Page - OSRAM GmbH

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