Metrix 440/450 electronic vibration switches, available from Measurement Solutions , utilise a solid state crystal accelerometer and 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 Metrix 440 vibration switches except when configured with mechanical relays. An important feature of Metrix 440/450 electronic vibration 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 caused by transitory vibrations occurring during start-up.
Most 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 operators turn the trip setting up until they 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 field over a range of 2 to 15 seconds.
Metrix 440/450 electronic vibration switches have the following 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
- Analogue dial for setting limits
- Solid state relay contacts used for alarm and/or shutdown
- Field settable for close on alarm (N.O.) or open on alarm (N.C.)
- Remote reset capability
- Provision for self-test and calibration
- 4 to 20mA output available
- Built-in transducer or optional remote transducer
- Cast aluminium enclosures meet NEMA 3, 4 and 12 standards
- Explosion-proof models (450 series) available