The Bently Nevada 991-25-70-01-CN, also cataloged as the 991 Thrust Transmitter, operates as a dedicated hardware component for axial position signal conditioning within rotating machinery protection loops.
Suffix Breakdown & Model Matrix
| Option Code | Option Description | Technical Definition |
|---|---|---|
| 991 | Base Model | Thrust Transmitter |
| -25 | Full-scale Option | 25-0-25 mils (+/-25 mils) full-scale axial displacement range |
| -70 | System Length Option | 7.0 metres (23.0 feet) calibrated total system length |
| -01 | Mounting Option | 35 mm DIN-rail clips installed |
| -CN | Agency Approval Option | Not required |
Hardware Specifications
| Parameter | Specification |
|---|---|
| Model | 991-25-70-01-CN |
| Brand | Bently Nevada |
| Origin | USA |
| Product Type | Thrust Transmitters |
| Measurement Type | Axial shaft displacement (thrust position) |
| Full-Scale Range | 25-0-25 mils (+/-25 mils) |
| System Cable Length | 7.0 metres (23.0 feet) |
| Output Signal | Proportional 4-20 mA loop current |
| Mounting Interface | 35 mm DIN-rail clips |
| Agency Approvals | Not required (-CN option) |
| Power Consumption | Loop-powered via output 4-20 mA current interface |
Eddy-Current Probe Scaling & Gap Voltage Validation (-10 VDC Targets)
The 991 transmitter accepts non-contacting eddy-current proximity sensor inputs over a factory-tuned 7.0-metre total system length. System commissioning mandates physical gap voltage validation across test terminals to verify the static baseline bias target of -10 VDC when the machine shaft resides at mechanical mid-span. Internal eddy-current probe scaling processes transducer impedance changes into a proportional 4-20 mA current output across the calibrated 25-0-25 mils physical span.
Frequently Asked Questions
Q: How is primary loop power provided to the 991-25-70-01-CN module terminals?
A: Operating power is drawn directly from the 2-wire 4-20 mA output current loop circuit connected to the host automation system.
Q: Can extension cable lengths be modified in the field without affecting scaling accuracy?
A: No, the 7.0-metre system length is factory-calibrated to specific probe inductance and line capacitance; altering cable lengths compromises output scaling.
Q: What physical mounting mechanism is included with the -01 option?
A: The -01 mounting option includes factory-fitted mounting clips for direct installation onto standard 35 mm DIN rails.
Field Installation Guidelines
- Snap the module securely onto an industrial 35 mm DIN rail inside a protective field panel.
- Fasten the 7.0-metre proximity probe extension cable coaxial connector to the transmitter input jack, securing it hand-tight.
- Validate static DC gap voltage using a multimeter across raw signal terminals, adjusting probe depth to achieve the -10 VDC target at mechanical center.
- Route 2-wire shielded twisted-pair conductors from the output terminals to the host control panel current loop input.
- Terminate the cable drain shield at a single earthing point on the main cabinet bus bar to mitigate ground noise and cross-talk interference.
What's clients say about us
Excellent Emergency Support!
Our production line was down due to a faulty Bently Nevada monitor. We found it in stock here and they shipped it via DHL immediately. Back in operation within 48 hours—truly a lifesaver for our plant.
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Maintenance Manager, USAReliable Source for New Spares
Finding brand new, original modules is critical for our safety. This team delivers factory-fresh components with full certification. Their commitment to only selling new products makes them our most trusted partner.
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Engineering Lead, GermanyTop-tier Service and Quality
We have sourced Honeywell and Schneider parts here for two years. Every shipment arrives well-packaged with original factory seals intact. Clear communication and the best lead times in the industry.
Lucas Müller
Operations Director, GermanyRelated Products
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Guide
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