Product Introduction
With a full-scale range of 0–10 mils pp and a frequency response of 5 Hz to 6,000 Hz, the Bently Nevada 990-10-70-03-CN is engineered for reliable vibration monitoring in rotating machinery. This 990 Vibration Transmitter accepts one non-contacting 3300 NSv Proximity Probe and extension cable, converting displacement signals into a standard 4–20 mA output. Its fast NOT OK signal defeat function ensures immediate fault detection, minimizing downtime and protecting critical assets.
Technical Specifications Overview
The Bently Nevada 990-10-70-03-CN provides a 4–20 mA loop accuracy within ±1.5% over the full-scale range. Key specifications extracted from the product database include:
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Power Supply: Requires +12 to +35 Vdc input at the transmitter terminal.
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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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Frequency Response: 5 Hz to 6,000 Hz +0, 3 dB.
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Probe Gap: Must be gapped between 0.5 and 1.75 mm (20 and 55 mils) from target.
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Minimum Target Size: 9.5 mm (0.375 in) diameter.
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NOT OK/Signal Defeat: Signal output goes below 3.6 mA within 100 µs after a Not OK condition, restoring in 2–3 seconds after removal.
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Weight: 0.43 kg (0.9 lbm).
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Mounting Option: DIN clips and screws (Option 03).
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System Length: 7.0 meters (23.0 feet) cable (Option 70).
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Full-Scale Option: 0–10 mils pp (0–250 μm pp).
Real-World Applications
The Bently Nevada 990-10-70-03-CN excels in monitoring shaft vibration on turbines, compressors, pumps, and fans. In a typical steam turbine installation, the transmitter provides continuous 4–20 mA data to a DCS or PLC, enabling early detection of imbalance or misalignment. Its fast NOT OK signal defeat triggers an alarm within 100 µs of a fault, allowing operators to shut down the machine before catastrophic failure occurs. This capability directly reduces unplanned downtime and maintenance costs, making it a cost-effective choice for predictive maintenance programs.
Installation and Setup Guidance
Mount the Bently Nevada 990-10-70-03-CN using the provided DIN clips and screws (Mounting Option 03). Ensure the probe is gapped between 0.5 and 1.75 mm from the target surface, and use the included 7.0-meter cable for the 3300 NSv Proximity Sensor. The transmitter accepts +12 to +35 Vdc; verify polarity and voltage before connection. For Non‑Hazardous, Zone 2, or Div 2 locations, a 28 V power supply is recommended. Adjust zero and span via non-interacting external adjustments without opening the housing. The leadwire from the BNC connector must not exceed 3 meters (10 feet) to maintain signal integrity.
Maintenance and Reliability
Routine inspection of the Bently Nevada 990-10-70-03-CN involves verifying the probe gap and checking for cable damage. The transmitter’s current limiting (23 mA typical) protects the loop from overloads, while the zero and span adjustments stay stable over time. The NOT OK/signal defeat circuit automatically drives the output below 3.6 mA during a fault, ensuring failsafe operation. With no moving parts and a sealed enclosure, this unit requires minimal maintenance—periodic calibration every 12 months is sufficient. Its robust design supports continuous use in harsh industrial environments, aligning with a failure-mode‑prevention strategy.
Selection Guide and Purchasing Advice
Before ordering a Bently Nevada 990-10-70-03-CN, confirm the full-scale range (0–10 mils pp), system length (7.0 meters), mounting (DIN clips and screws), and agency approval option (CN for country‑specific approvals). This transmitter works with any 3300 NSv proximity probe; ensure the probe and extension cable are compatible. For pricing and availability, contact PLC Source PRO at ubest101.myshopify.com. Choose this module to equip your plant with a field‑proven vibration monitoring solution that combines accuracy, fast fault response, and rugged construction.