Product Introduction
When machinery vibration exceeds safe limits, the Bently Nevada 990-04-70-02-05 provides critical early warning. This 990 Vibration Transmitter accepts one non-contacting 3300 NSv Proximity Probe and delivers a 4-20 mA signal proportional to full-scale range. Designed for hazardous environments, it includes CSA Division 2, ATEX Zone 0/2, and ABS maritime approvals. The 990-04-70-02-05 is built for continuous, reliable operation in demanding industrial settings.
Technical Specifications
| Parameter |
Value |
| Input |
Accepts 1 non-contacting 3300 NSv Proximity Probe and extension cable |
| Power |
+12 to +35 Vdc at transmitter terminal |
| Output |
4-20 mAdc over specified full-scale range (2-wire) |
| Loop Accuracy |
Within ±1.5% over full-scale range |
| Maximum Loop Resistance |
1,000 Ω including cable at 35 Vdc |
| Current Limiting |
23 mA typical |
| Frequency Response |
5 Hz to 6,000 Hz +0, 3 dB |
| Probe Gap |
0.5 to 1.75 mm (20 to 55 mils) |
| Minimum Target Size |
9.5 mm (0.375 in) diameter |
| Weight |
0.43 kg (0.9 lbm) |
Failure Mode Analysis & Practical Benefits
The Bently Nevada 990-04-70-02-05 excels in preventing undetected vibration events. Its NOT OK/signal defeat function forces the output below 3.6 mA within 100 µs after a fault, ensuring downstream systems recognize the problem. The non-interacting zero and span adjustments allow quick recalibration without cross-effects. Loop accuracy of ±1.5% (plus probe factor) provides reliable data for predictive maintenance.
Application Examples
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Pump monitoring: Detect bearing wear and imbalance in centrifugal pumps using the 0-4 mils pp full-scale.
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Fan and blower systems: The 5 Hz to 6 kHz response captures both low-speed and high-frequency vibration.
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Compressor protection: In ATEX Zone 2 environments, the transmitter provides continuous 4-20 mA signals to trip systems before damage occurs.
Installation & Setup Guidance
Mount the Bently Nevada 990-04-70-02-05 using the bulkhead screws (Mouting Option 02). Ensure the 3300 NSv probe gap is set between 0.5 and 1.75 mm from the target. Use extension cable up to 3 meters (10 feet) from the Proximitor Sensor Output (BNC connector). Apply +12 to +35 Vdc at the transmitter terminals; maximum loop resistance is 1,000 Ω at 35 Vdc. Verify zero and span with the non-interacting adjustments after installation.
Maintenance & Reliability
Periodically check the probe gap and cable connections. The transmitter self-monitors; if the NOT OK condition triggers, investigate probe condition or power supply. After a fault clears, the output restores within 2-3 seconds. The ceramic-coated sensor target and robust enclosure withstand harsh industrial environments. Regular zero/span verification ensures sustained accuracy.
Selection Guide & Purchasing Advice
Before purchasing, confirm your probe type (3300 NSv) and system length (7.0 meters in this variant). The agency approval option 05 includes CSA Division 2, ATEX Zone 0/2, and ABS maritime – verify compatibility with your area classification. For reliable sourcing, PLC Source PRO (formerly ubest101) stocks genuine Bently Nevada modules with proven traceability.