V20W Datasheet, PDF (6/24 Pages) List of Unclassifed Manufacturers – PIEZOELECTRIC ENERGY HARVESTERS

OPERATION
Straight clamps are the simplest and often most cost
effective clamps. However, curved clamps, as shown
in the diagram below, have shown the capability to
slightly increase performance of the Volture. Straight
clamps are sufficient for the majority of applications.
Tuning The Volture™
To ensure the most efficient harvesting, it is essential to
tune the Volture’s™ natural frequency to match that of
the vibrating source. Tuning is performed by adding a
tuning mass to the end of the cantilevered Volture™
CURVE CLAMP
until the natural frequency of the piezo beam is the
same as the vibration source. The larger the tuning
mass the lower the natural frequency of the Volture™.
For non permanent installations or for active tuning it is
best to use bee’s wax or some other form of non-
permanent attachment for the tuning mass to the
Volture. Bee’s wax allows the mass to be moved along
the beam, toward and away from the clamp, for tuning.
There are multiple means of tuning the Volture™
depending on the equipment available to the user. If
only the vibration source that will ultimately be
harvested from is available to the user, it is
recommended that the Volture™ be properly mounted
and clamped to the vibration source. The output of the
Volture should then be attached to an oscilloscope for
monitoring. The output can be either the raw output of
the Volture™ (directly on two of the output pins) or
through whatever electronics the user is using so long
as the electronics allow for some measure of optimal
power output. The tuning mass can then be adjusted
until the maximum power is achieved.
If the user has a shaker available, the tuning can be
performed by driving the Volture™ at the desired
natural frequency and adjusting the mass until optimal
power output is achieved. If connecting directly to the
Volture™ pins, optimal power output will be where the
voltage output is maximized.
Another simple way to tune your Volture™ product is to
measure the frequency at which the device "rings out"
when excited by an impulse mechanical load. The
easiest way to perform this type of tuning is to properly
mount and clamp the Volture to a rigid structure. Next,
attach at least one of the piezo's within the Volture
directly to an oscilloscope for monitoring (ex: connect
to pins P1 and P2). Add the appropriate tip mass (See
RELATION BETWEEN TIP MASS & NATURAL
FREQUENCY section) to the end of the cantilevered
Volture, do not permanently adhere the tip mass yet.
Bee's wax or tape is often the best material to use for
non permanent tip mass installations. Apply an impulse
mechanical load by very lightly "flicking" the end of the
Volture. This will cause the beam to "ring out". The
frequency of the the decaying wave is the natural
frequency that the Volture is currently tuned to. To
decrease this frequency move the mass farther away
from the clamp point, to increase the frequency move
the mass closer to the clamp point. If the natural
frequency is not close to the desired frequency either a
different tip mass or a different product may be
required.
Once the tip mass is in the proper location for optimal
energy harvesting it should be permanently adhered to
the Volture™. This ensures that the tip mass remains in
place for the life of the Volture™. It is recommended
that a robust adhesive such as Loctite™ 404 be used
for this permanent installation. Keep in mind that any
added mass will impact the tuning of the system.
REVISION N0. 002 REVISION DATE: 01-23-2013
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