991 Thrust Transmitter Bently Nevada 991-25-70-02-01

Overview

The Bently Nevada 991 Thrust Transmitter (Product No. 991-25-70-02-01) is a precision device primarily used for centrifugal air compressors, motors, small pumps, or fans. The transmitter offers OEMs a reliable solution for providing a 4-20 mA proportional axial displacement (thrust) signal to their machinery control systems.

Technical Specifications

• Manufacturer: Bently Nevada
• Product Number: 991-25-70-02-01
• Product Type: Thrust Transmitter
• Full-scale Options: 2, 5, 25-0-25 mils
• System Length Options: 7.0 meters (23.0 feet)
• Mounting Option: Bulkhead screws
• Power Requirements: +12 to +35 Vdc input
• Accuracy: ±1.5% over specified full scale range (typical)
• Signal Output: 4-20 mA (loop-powered)
• Maximum Loop Resistance: 1,000 Ω including cable at 35 Vdc
• Current Limiting: 23 mA typical
• Transmitter Weight: 0.43 kg (0.9 lb)
• Transducer Tip Material: Polyphenylene sulfide (PPS)
• Probe Cable: 75Ω coaxial, fluoroethylene propylene (FEP) insulated
• Probe Cable Armor (Optional): AISI 302 SST with optional FEP outer jacket
• Proximity Sensor Output Impedance: 10 kΩ calibrated for a 10 MΩ load
• Linear Range: 0.25 to 1.65 mm (10 to 65 mils)
• Temperature Stability: Scale factor remains within ±10% from 0°C to +70°C (+32°F to +158°F)
• Leadwire Length: Maximum 3 meters (10 feet) for proximitor sensor output
• Maximum Distance Between Transmitter and Receiving Device: 13 km (8 miles)

FAQ

1. What type of probe does the 991 Thrust Transmitter use?
   • The transmitter is compatible with the 3300 NSv proximity probe, which provides non-contact axial displacement measurement.
2. What is the output signal from the transmitter?
   • The transmitter provides a 4-20 mA output signal, proportional to the shaft’s axial position.
3. What is the accuracy of the 991 Thrust Transmitter?
   • The accuracy is typically ±1.5% over the specified full-scale range.
4. Can the transmitter be used in hazardous environments?
   • Yes, the transmitter is available with CSA Division 2 approval for use in hazardous locations.
5. What is the maximum cable length for the proximitor sensor?
   • The maximum leadwire length for the proximitor sensor output is 3 meters (10 feet).

For more detailed information:991 Thrust Transmitter Datasheet