Configured for axial position measurement using eddy-current probe input signals, the Bently Nevada 991-25-70-01-01 (991 Thrust Transmitter) provides direct physical/electrical execution for converting shaft displacement signals into proportional current loop output.
Hardware Specifications
Parameter
Specification
Model
991-25-70-01-01
Brand
Bently Nevada
Product Type
Thrust Transmitter
Origin
USA
Weight
0.44 kg
Dimensions
10 cm x 7.5 cm x 5.2 cm
Operating Temp
Not specified
Power Consumption
Requires +12 to +35 VDC input at transmitter terminal
Input Signal
Eddy-current probe displacement input
Output Signal
4-20 mA proportional current output
Cable Length Option
7.0 metres (23.0 feet)
Mounting Type
35 mm DIN rail clips
Certification
CSA Division 2
Maximum Loop Resistance
1,000 ohm including cable at 35 VDC
Current Limiting
23 mA typical
Tariff Code
8537101190
Eddy-Current Probe Scaling and Rotor Position Measurement
The Bently Nevada 991-25-70-01-01 processes eddy-current probe signals for axial shaft displacement monitoring. The transmitter scales probe voltage variations into a standardized 4-20 mA output signal for integration with monitoring and control systems.
The measurement circuit supports gap voltage validation based on eddy-current probe operating characteristics. Bently Nevada proximity measurement systems commonly use -10 VDC gap voltage targets for probe positioning verification and signal conditioning reference.
The transmitter interface is designed for rotor dynamics applications where thrust position changes must be converted into continuous electrical measurements. Signal conditioning functions maintain measurement stability while reducing the influence of electrical interference and cross-talk between monitoring channels.
Frequently Asked Questions
Q: What input signal does the Bently Nevada 991-25-70-01-01 process? A: The transmitter accepts displacement signals from compatible eddy-current proximity probe systems and converts them into a proportional current output.
Q: What power supply range is required for operation? A: The unit requires +12 to +35 VDC input at the transmitter terminal.
Q: What is the maximum allowable loop resistance? A: The maximum loop resistance is 1,000 ohm including cable when operating with a 35 VDC supply.
Field Installation Guidelines
Install the transmitter on a suitable 35 mm DIN rail using the specified mounting clips. Verify wiring polarity before applying DC power.
Route probe signal cables separately from high-voltage power conductors to reduce electromagnetic interference. Use appropriate cable shielding practices and connect shields according to the plant grounding standard.
Confirm the proximity probe installation position and verify the electrical gap condition before commissioning. Check the 4-20 mA output response against the expected shaft displacement range after installation.
