Product Introduction
When vibration monitoring systems falter, costly downtime follows. The Bently Nevada 990-10-50-01-CN 990 Vibration Transmitter delivers precise shaft vibration measurement for critical rotating machinery. This Industrial Automation Module accepts one non-contacting 3300 NSv proximity probe and extension cable, providing a 4–20 mA output proportional to full-scale range (0–10 mils pp / 0–250 µm pp). It operates on +12 to +35 Vdc power and includes 35 mm DIN rail clips for easy mounting. Manufactured in the U.S.A., the 990-10-50-01-CN ensures trustworthy performance in Bently Nevada systems.
Technical Specifications
The Bently Nevada 990-10-50-01-CN packs essential features for industrial environments:
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Input: One 3300 NSv proximity probe and extension cable.
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Power: +12 to +35 Vdc at the transmitter terminal.
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4–20 mA Loop Accuracy: Within ±1.5% over full-scale range (measured across 250 Ω).
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Frequency Response: 5 Hz to 6,000 Hz +0, –3 dB.
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NOT OK/Signal Defeat: Output drops below 3.6 mA within 100 µs of a fault; restores within 2–3 seconds after fault clears.
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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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Weight: 0.43 kg (0.9 lbm).
These specs ensure reliable data transmission and fault detection.
Industry Applications
The 990-10-50-01-CN excels in monitoring vibration on turbines, compressors, pumps, and motors. Its ±1.5% accuracy and wide frequency response capture critical low-frequency and high-frequency events. In a compressor train, the transmitter's rapid NOT OK response (under 100 µs) alerts operators to probe damage or cable faults, preventing catastrophic failures. For generator monitoring, the 5 Hz–6 kHz range covers both slow shaft rotation and blade-pass frequencies.
Installation & Setup Guidance
Mount the 990-10-50-01-CN using the provided 35 mm DIN rail clips. Gap the proximity probe between 0.5 and 1.75 mm (20–55 mils) from the target to achieve full-scale range. Use the non-interacting zero and span adjustments for calibration. The BNC connector output has a maximum cable length of 3 meters (10 feet). Ensure total loop resistance including cable stays under 1,000 Ω at 35 Vdc to maintain 4–20 mA accuracy.
Maintenance & Reliability
To maximize uptime, periodically verify probe gap and loop resistance. The transmitter's current limiting (23 mA typical) protects the loop from short circuits. The NOT OK feature automatically forces output below 3.6 mA during faults, ensuring safe diagnostics. For extreme environments, the unit supports non-hazardous, Zone 2, or Division 2 hazardous locations with a 28 V power supply. Routine checks of the 3300 NSv probe extension cable prevent signal degradation.
Troubleshooting & Common Issues
If output remains at 4 mA or saturates at 20 mA, check probe gap and verify power between +12 and +35 Vdc. A loop resistance exceeding 1,000 Ω will reduce accuracy—use lower-resistance cable or increase supply voltage. If the transmitter fails to respond, measure current limiting (should be ~23 mA). The NOT OK latch clears within 2–3 seconds after the fault condition is removed. For persistent errors, inspect the probe connection at the BNC.