2.5. Luminaire design and EMI performance
The degree of electromagnetic compatibility (EMC) is basically
determined by the high frequency ballast concept in combination
with the luminaire design. Taking the following basic rules into
consideration will optimize the EMC behavior of the system and
help to fulfill the requirements. The basic rules are valid for both PL
and TL applications where functional and/or protective ground is
required. Functional ground can be required in order to fulfill the
EMC requirements or to guarantee proper operation of the system.
It means that an ignition aid or other metal surfaces are necessary,
which should be connected electrically to the housing of the ballast.
1. Ensure a firm electrical connection between the ballast and the
metal luminaire.The contact resistance has to be as small as
possible, so affix the ballast directly to the luminaire. The use of
additional mounting plates or several junctions has a negative
influence on EMC.
2. Keep the lamp wiring short. Avoid redundant wiring, e.g. loops.
The so-called ‘hot’ wires should be the shortest and have the
same (symmetrical) length for two lamp ballasts.
3. Keep the mains wiring far away from lamp wiring. Ensure that the
mains wiring inside the luminaire is as short as possible. Minimize
stray capacitance by ensuring that mains wiring does
not run parallel to lamp wiring.
4. Provide good electrical contact between the metal luminaire and
reflector and/or louver.
5. Use a shielding around the lamp, well connected to the luminaire.
This will help to reduce surrounding currents.
6. Minimize capacitance between wires and the luminaire. If possible,
mount the lamp wiring on spacers. Do not group wires by
means of tie wraps.
For more examples and background information visit:
www.advancetransformer.com
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OEM Design Guide
Philips T5 VHO and HO Extreme Temperature Lamps and Ballasts
