مفتاح الأهتزاز MODEL 66

OVERVIEW
The Vibration Switch is a safety device, which quickly detects
abnormalities in mechanical equipment in order to help prevent
breakdown. It is designed in accordance with Japanese
explosion-proof standard (66EJ) to enable users to employ it in
places where there is a risk of explosion.
The reliable performance of the Vibration Switch is time proven -
it has received very favorable user response from the time it was
first marketed over 30 years ago.
Construction of DETECTOR
If the detector is subjected to vibration acceleration in the
"Direction of vibration", a moment will be set up around the
spring joint of the armature, tending to separate the armature
from magnet below it. Similarly, the adjusting spring will also
generate a moment around the spring joint, tending to separate
the armature from the magnet. When the sum of these moments
is larger than the moment acting around the spring joint due to
the magnet attracting the armature, the armature will come away
from the stop pin below. As the result of the motion of the
armature, a micro-switch will be actuated, triggering an alarm
signal.
Type of DETECTOR
The Vibration Switch is available in a weather-resistant version and an explosion-proof
version to suit various applications.
DETECTOR
Detectors used with the Vibration Switch are installed directly on
the pump, motor and fan of the piece of equipment to be
monitored in order to detect abnormal vibration due to a
mechanical failure of these units in terms of acceleration.
Generally, if a breakdown occurs in mechanical equipment
driven by an electric motor or internal combustion engine, such
phenomena as temperature rise, increased noise and excessive
current will occur. In addition, "Abnormal Vibration" always
occurs along with these phenomena.
This abnormal vibration consists of 2 elements; abnormal
frequency (number of vibrations per second) and abnormal
amplitude.
Consequently, when safeguarding a piece of equipment by the
method of detecting abnormal vibration, it is not sufficient to
detect only one of these elements.
For example, if the amplitude of the vibration is measured using
an amplitude meter, it will not be possible to detect a frequency
abnormality. Also an abnormal amplitude resulting from
eccentricity of a piece of rotating machinery will not show up in
the vibration frequency.
A Vibration Switch detector detects abnormal vibration by means
of acceleration, which is common to both amplitude and
frequency.