Vibrating wire micro strain gauge
The vibrating wire micro strain gage is designed to measure strain in metal structures and reinforcement bars in situations where the space available for the installation is very limited. It is used for monitoring sensitive structures where it is not possible to use arc welding of where this service is not available. The instrument consists basically in a small steel wire tensioned between two blocks welded on the surface to be monitored. Deformation of the structure under load changes the distance between the two blocks with consequent change in the tension of the wire, which when energized with an electrical input generates a resonance frequency. This frequency, measured by an electromagnetic coil, is proportional to the length of the wire and therefore to the tension to which is subjected, thus giving a measurement of the strain in the support.
The advantage of this type of instruments is the excellent long-term stability of the measurement and the output signal in Hz which is suitable for transmission through very long cables. The sensor includes a thermistor for measurement of temperature changes.
- Type of transducer: vibrating wire;
- Nominal measuring range: +/- 1750 µƐ;
- Sensitivity: 1 µƐ;
- Accuracy: <0.5 % F.S.;
- Non Linearity: better than 0.5% F.S.;
- Wire length: 57 mm;
- Temperature Range: -30 °C to +80°C;
- Integrated temperature sensor: NTC 3KΩ;
- Typical frequency: 2800 Hz;
- Output signal: Hz;
- Thermal expansion coefficient: 12,2 µƐ/°C.
- Total length: 63.5 mm
- Body length: 57 mm
- Vibrating wire length: 51 mm
- Body diameter: 6 mm