Technical information

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HF-ballast
Why HF-ballasts?
Research studies have indicated that people in workplaces where
luminaires equipped with HF-ballasts are used feel better, are less
tired and achieve more. Not everyone is aware of the icker from
fluorescent lamp luminaires equipped with ordinary ballasts, how-
ever the brain still registers the flashing.
As the HF-ballast utilises energy more eciently, i.e. the installed
luminaire output and performance losses are lower, there is also
less heat. Thanks to this, cooling and air conditioning equipment
can be dimensioned with a reduced output, giving both purchasing
and operation cost savings.
Maintenance and service costs are lower due to the increased life
of the light sources. When re-lamping you no longer need to change
the starter, as the ignition function is integrated in the HF-ballast.
HF-ballasts are the environmental choice
HF-ballasts are environmentally friendly. The HF-ballast makes the
greatest contribution towards the environment through energy sav-
ings. Another important environmental factor is that the life span of
the fluorescent lamp increases on average by 15 %, which reduces
the mercury load on the surroundings.
Function
An HF-ballast increases the uorescent lamp’s working frequency to
approximately 40 kHz, and in doing so lights the uorescent lamp
completely evenly without flashing. At the same time eciency is
improved by approximately 10 %.
Ignition
An HF-ballast ignites fluorescent lamps in a controlled manner. The
warm start means that uneven emissions from the cathodes are
avoided, which is considered to extend the life span by up to 50 %
where the switching on and o rate is deemed as normal. Using
a warm start HF ballast, the cathodes are preheated before the
fluorescent lamp receives its ignition pulse. In addition, modern
high quality HF-ballasts have a function that significantly reduces or
completely cuts this preheating current once the fluorescent lamp
has ignited. An important function when taking energy savings
into consideration, but also it means the T5 light source is powered
under optimal temperature conditions.
Operation
When discharging starts and the fluorescent lamp ignites, the HF-
ballast regulates all unnecessary parameters for an even luminous
flux independent of fluctuations in the supply voltage. Further-
more, the HF-ballast monitors the function of the light source and
switches it o if defects occur. There are HF-ballasts on the market
that can indicate, via the light source, that a mains voltage fault has
occurred, for example, over voltage.
Cable routing
A great deal of thought must be given to cable routing when de-
signing luminaires for HF-ballasts.
Internal wiring to the fluorescent lamp must be routed in a way
that does not impair functionality. Too long internal wiring to the
fluorescent lamp can also cause interference issues (EMC).
Furthermore, the incoming mains cable must be taken into
consideration. The mains cable, due to EMC requirements, must not
be routed together with internal wiring. For this reason luminaires
usually feature a separate channel or row of clips to correctly route
these cables.
Master–slave
Master-slave solutions, where two interconnected luminaires are
fed by a single HF-ballast placed in one of the units, can only be
recommended for HF-standard and where internal wiring can be
kept shorter than 1 m. Master-slave solutions for HF-dimming are
not recommended due to the very high risk of defective functional-
ity (dierent light levels from the luminaires).
In the master-slave solutions for Dimming, only the control signal
from the HF-ballast of the master luminaire should be considered;
this then controls the HF-ballast in the slave luminaire, which is not
the same procedure as the one described above.
Advantages of HF-ballasts:
Quick, icker free ignition.•
Flicker free lighting. •
Very small magnetic field. •
The light source works under optimal conditions and gives the correct luminous ux •
independent of fluctuations in the supply voltage.
Extends the life span of the light source.•
Low harmonics (THD).•
Switches o defective fluorescent lamps (no disturbing flashing).•
Save 20 % energy on average. A 60 % saving is possible through dimming, constant •
light control and/or with occupancy detection.
Dimming of fluorescent lamps is only possible with HF-ballasts. •
Low thermal loss. •
No stroboscopic eect.•
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