Product Introduction
The Bently Nevada 991-06-50-03-01 is a precision Probe Vibration Transmitter designed for axial thrust monitoring in rotating machinery. Part of the 991 series, this transmitter converts proximity probe signals into a 4-20 mA current loop output, providing continuous, reliable data for critical asset protection. With its built-in Not OK/Signal Defeat function, the 991-06-50-03-01 ensures immediate fault indication (output drops below 3.6 mA within 100 µs) to prevent undetected failures.
Technical Specifications
Key parameters of the Bently Nevada 991-06-50-03-01 include:
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Output Signal: 4-20 mAdc over specified full-scale range, 2-wire configuration
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Power Supply: +12 to +35 Vdc at transmitter terminal
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Accuracy: Within ±1.5% of full scale (typical), measured across 250 Ω loop resistance
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Linear Range: 0.25 to 1.65 mm for Prox Out; supports 0.6-0-0.6 mm or 25-0-25 mils full-scale
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Maximum Loop Resistance: 1,000 Ω including cable at 35 Vdc
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Current Limiting: 23 mA typical
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Operating Temperature: -35°C to +85°C
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Storage Temperature: -51°C to +100°C
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Weight: 0.43 kg (0.9 lbm)
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Mounting: DIN rail with DIN clips and screws
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Agency Approval: CSA Division 2
Industry Applications
This Bently Nevada 991-06-50-03-01 transmitter excels in monitoring axial shaft position and thrust wear in turbines, compressors, pumps, and generators. Its 4-20 mA output integrates seamlessly with PLCs and DCS systems. The signal defeat feature is critical in safety instrumented systems where immediate fault detection prevents catastrophic failures.
Installation Guide
Mount the Bently Nevada 991-06-50-03-01 on a standard DIN rail using the provided clips and screws. Connect a single 3300 NSv proximity probe and extension cable. Power the transmitter with +12 to +35 Vdc. The 4-20 mA loop must be wired in 2-wire configuration, respecting maximum loop resistance of 1,000 Ω. Use non-interacting external adjustments for zero and span calibration.
Troubleshooting Common Issues
If output falls below 3.6 mA, the Bently Nevada 991-06-50-03-01 indicates a Not OK condition. Check probe integrity, cable continuity, and supply voltage. For accuracy drift, verify loop resistance and recalibrate. The current limiter (23 mA) protects against short circuits. Storage temperature must stay within -51°C to +100°C to avoid damage.