Why we use Negative Voltage in Vibration Measurement?

Why we use Negative Voltage in Vibration Measurement ?

Vibration sensors, particularly those used in Bently Nevada systems, often use negative voltages for vibration measurement. The main reasons are:

Maintaining a Stable Gap Voltage

  • Using a negative voltage helps maintain a stable gap voltage between the sensor and the target surface, which is crucial for accurate vibration measurement.
  • If the gap voltage were positive, any fluctuations in the gap distance could cause the voltage to become zero or positive, leading to measurement errors or even sensor failure.

Preventing Sensor Saturation

  • Negative voltage helps prevent sensor saturation, which can occur when the target surface gets too close to the sensor.
  • If the sensor saturates, it can no longer accurately measure vibration, leading to incorrect readings or even sensor damage.

Improving Signal-to-Noise Ratio

  • Using negative voltage helps improve the signal-to-noise ratio of the vibration measurement system.
  • This is because negative voltage reduces the amount of electrical noise present in the system, making it easier to detect and measure the actual vibration signal.

Compatibility with Existing Systems

  • Many industrial machinery monitoring systems, such as Bently Nevada systems, are designed to work with negative voltage vibration sensors.
  • Using negative voltage ensures compatibility with these existing systems, allowing for seamless integration and reliable vibration monitoring.

Reducing Sensor Drift

  • Negative voltage helps reduce sensor drift over time, which is the gradual change in the sensor’s output due to factors such as temperature or aging.
  • By maintaining a stable gap voltage, negative voltage helps minimize sensor drift, ensuring consistent and reliable vibration measurements throughout the sensor’s lifetime.

The use of negative voltage in vibration measurement is a well-established practice that offers several benefits, including maintaining a stable gap voltage, preventing sensor saturation, improving signal-to-noise ratio, ensuring compatibility with existing systems, and reducing sensor drift. These advantages make negative voltage an essential aspect of vibration monitoring in high-speed rotating equipment.