Overview

The Bently Nevada Seismoprobe Velocity Transducer Systems are specifically engineered to measure absolute vibration—relative to free space—on bearing housings, casings, or structural components. These systems feature a two-wire configuration, comprising a transducer and a compatible cable.

The Seismoprobe family of velocity transducers features a two-wire design utilizing advanced moving-coil technology. This design offers a direct voltage output that is proportional to the vibration velocity detected by the transducer.

Unlike solid-state velocity transducers, which rely on accelerometers with embedded integration electronics, moving-coil transducers are less sensitive to impact or impulsive excitations. This makes them a suitable option for applications where durability and accuracy in fluctuating conditions are critical.

Furthermore, moving-coil transducers do not require external power, making them an ideal choice for portable measurement applications where convenience and reliability are essential.

Specifications

Electrical

• Sensitivity:
  • 20 mV/mm/s (500 mV/in/s), ±5% when properly terminated and oriented at the angle of calibration.
• Calibration Load:
  • 10 kΩ Terminal "A" to "B"
  • Output taken across pins "A" and "B"
• Sensitivity Temperature Coefficient:
  • 0.2%/°C
• Velocity Range:
  • 25 mm/s (1 in/s) (at +22 °C of casing vibration at 100 Hz with a 10 kΩ load)
• Coil Resistance:
  • 1.25 kΩ ±5%
• Locked Coil Inductance:
  • 125 mH, typical

Environmental Limits

• Operating and Storage Temperature:
  • 9200: -29°C to +121°C (-20°F to +250°F)
  • 74712: -29°C to +204°C (-20°F to +400°F)
• Relative Humidity:
  • To 95%, non-condensing
  • 100%, non-submerged, when ordered with integral cable

Physical

• Height:
  • 102 mm (4 in) typical (depending on connector option)
• Diameter:
  • 41 mm (1.6 in) typical
• Weight:
  • 9200: 300 grams (10.5 ounces) typical
  • 74712: 480 grams (17 ounces) typical