440/450 Switch0 pages

Electronic Vibration Switch
440 & 450
440/450 electronic switches utilize a solid state crystal accelerometer which
provides an electrical output when it is deformed by the vibration forces. The
output is electronically converted to a signal proportional to velocity. This signal
is compared with a preset limit and triggers a solid state relay if the limit is exceeded. There are no moving parts in the 440 vibration switches except when
congured with mechanical relays.
While the 440 costs more than a mechanical switch, it uses the same technology as sophisticated remote monitoring systems and provides most of the
capabilities of these systems at 1/3 to 1/2 the cost per monitor point.
An important feature of these switches is the built-in time delay. This prevents
triggering of the alarm or shutdown functions from transient increases in vibration levels. It also avoids shutdown due to transitory vibrations occurring during
start-up.
Almost all machines experience a few seconds of high vibration during start-up
before reaching operating speed. When no time delay function is included, as
with mechanical switches, this start-up vibration causes a trip. Frequently, the
operator turns the trip setting up until he can get through start-up. The resultant
trip level is too high to afford protection at the machine’s operating speed.
Three-second alarm trip delay is standard on these electronic switches. Alarm
time delays are independently adjustable in the eld over a range of 2 to 15
seconds.
SWITCHES
Features
• Built-in alarm time delay
• Reduce false triggering
• Velocity triggering provides protection
at all frequencies
• Sensitivity is not affected by rotating speed
of machinery
• Analog dial for setting limits
• Solid state relay contacts used for alarm
and/or shutdown
• Field settable for N.O. or N.C.
• Remote reset capability
• Provision for self-test and calibration
• 4-20 mA output available
• Built-in transducer or optional remote
transducer
• Cast aluminum enclosures meet NEMA 3,
4 and 12 standards
• Explosion-proof models (450 Series)
available
Built-in piezoelectric transducer module
with integral amplier provides 2 to 1,000
Hz capability.
Calibrated set point controls
enable operator to set specic
velocity trip points.
Light comes on immediately when
vibration exceeds set point (alarm or
shutdown will trip after 3 second time
delay).
Adjustable time delay of 2-15 seconds.
Factory set at 3 seconds.
Test position sets in minimum set point so
that any vibration will cause trip condition.
Light will come on immediately, and trip will
occur after duration of the time delay, proving that the complete system is operational.
If test position is maintained for less than
the duration of the time delay, trip will not
occur, thus permitting system test without
shutdown.
VDE approved terminal strip accepts #12 wire. Screw adjustable
clamping yoke rather than screw
terminal permits easy, vibration
proof connection. All hardware
is captive.
Each solid-state contact is independently eld settable to open on alarm
(N.C.) or close on alarm (N.O.).
4.04
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