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Many application opportunities for Electroluminescent Lamps and Power Supplies
are sensitive to excessive audible noise. These opportunities include retail,
residential and
commercial environments, museums, etc.
Lamp
Acoustical Issues
An electroluminescent panel operating in open air will emanate a tone and
harmonics centered around the operating frequency of the lamp, typically
650 Hz. The construction of the lamp as a flat, semi rigid panel causes
it to react much the same way a planar speaker works.
There are two primary solutions to this issue, when installing the lamp:
1. The lamp
may be coupled to a non-resonant surface. Using a double stick
tape (for
strip lamps), or a contact adhesive (for panel lamps), the lamp can be
bonded to a surface
that will deaden the vibrations. Typical surfaces include concrete, insulated
wood or
plaster walls, solid plastic or sintra panels at least ¼ inch thick,
MDF panels at least ¾
inch thick, or Styrene panels at least 1 inch thick. Hollow wood, plaster,
or drywall
surfaces will actually increase the volume of the noise, much as a guitar
or violin body
will amplify the vibrations of the strings.
2. The lamp
may be installed over a vinyl sound barrier. This is a high density
limp mass
material that is 1/8 inch thick, and is available in rolls 54 inches wide
and 60 feet
long. It is Fire Resistant, with a Class “A” rated version
available. The lamp must be
bonded to this backing for an effective installation.
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Care
must be taken to ensure a complete bond, without trapped air
pockets
that will allow the lamp to move independently in those areas.
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Never
bond the lamp directly to an un-grounded metal surface. When
installing
the lamp to metal, always ensure that the metal has a clean earth ground.
Power
Supply Acoustical Issues
Power Supplies will emanate an audible hum in certain configurations. Sometimes
this hum is caused by factors such as incorrect power supply for the given
lamp area or
incorrect voltage setting. Despite the cause, however, there is a straightforward
way of dealing
with this issue. As a high voltage / low current system, it is possible
to locate the supply as
much as 300 feet from the lamp in most instances. This allows the installation
of the supply in a
utility closet, basement, plenum space or other remote area where this
noise is not an issue.
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