What Is the Bently Nevada 990-04-50-02-01 Vibration Transmitter?
When vibration monitoring is critical for preventing catastrophic machinery failure, the Bently Nevada 990-04-50-02-01 provides a reliable solution. This 990 Vibration Transmitter accepts a single 3300 NSv proximity probe and delivers a precise 4-20 mA output proportional to shaft vibration. Designed for CSA Division 2 hazardous locations, it ensures continuous operation even in demanding environments.
Key Technical Specifications of Model 990-04-50-02-01
| Parameter |
Value |
| Full-Scale Range |
0-4 mils pp (0-100 μm pp) |
| System Length Option |
5.0 metres (16.4 feet) |
| Mounting Option |
Bulkhead screws |
| Agency Approval |
CSA Division 2 |
| Input |
Accepts 1 non-contacting 3300 NSv Proximity Probe |
| Power |
+12 to +35 Vdc |
| Maximum Loop Resistance |
1,000 Ω at 35 Vdc |
| Current Limiting |
23 mA typical |
| 4-20 mA Output |
4-20 mAdc over full-scale range, 2-wire |
| Loop Accuracy |
±1.5% of full-scale (over 250 Ω) |
| Probe Gap |
0.5 to 1.75 mm (20-55 mils) |
| NOT OK/Signal Defeat |
<3.6 mA within 100 µs; restored in 2-3 seconds |
| Frequency Response |
5 Hz to 6,000 Hz +0, -3 dB |
| Minimum Target Size |
9.5 mm (0.375 in) diameter |
| Leadwire Length (BNC) |
Maximum 3 meters (10 feet) |
| Hazardous Area |
Non-Hazardous, Zone 2, Div 2 (28 V supply) |
| Weight |
0.43 kg (0.9 lbm) |
Real-World Applications: Preventing Downtime with the 990-04-50-02-01
In rotating machinery such as turbines, pumps, and compressors, undetected vibration leads to premature bearing wear, shaft cracks, and unplanned outages. The Bently Nevada 990-04-50-02-01 delivers early warning by converting vibration amplitude into a standard 4-20 mA signal for DCS or PLC integration. Its NOT OK signal defeat function forces the output below 3.6 mA within 100 microseconds when the probe detects a fault, enabling immediate system shutdown. This rapid response minimizes equipment damage and reduces repair costs. For example, in a petrochemical plant compressor train, the 990-04-50-02-01 monitors radial vibration and triggers alarms before rubs occur, extending mean time between repairs.
Installation Guidance for the 990-04-50-02-01 Transmitter
Proper installation ensures accurate readings and long-term reliability. Follow these steps: Secure the transmitter using bulkhead screws (Mounting Option 02) onto a rigid mounting surface. Connect a compatible 3300 NSv proximity probe with extension cable; the total system length is 5.0 metres (16.4 feet). Set the probe gap between 0.5 and 1.75 mm (20-55 mils) from the target shaft to achieve the full-scale range. The BNC output leadwire must not exceed 3 meters (10 feet) to maintain signal integrity. Power the transmitter with +12 to +35 Vdc; use a 28 V supply for Div 2 areas. Verify loop resistance (max 1,000 Ω) to ensure 4-20 mA transmission over long distances.
Maintenance and Reliability: Ensuring Long-Term Performance
The Bently Nevada 990-04-50-02-01 is designed for minimal maintenance. Its self-diagnostic NOT OK functionality continuously checks loop health; if the output drops below 3.6 mA, inspect the probe gap, cable connections, and power supply. Current limiting at 23 mA typical prevents damage during transient faults. The 0.43 kg (0.9 lbm) robust package withstands industrial vibration and temperature extremes. Regular calibration is not required, but periodic testing of the 4-20 mA loop and probe gap ensures sustained accuracy. Choose this transmitter for applications where reliability is paramount, such as in oil and gas, power generation, and heavy manufacturing.
Selection Guide: Verifying Compatibility Before Purchase
When ordering the Bently Nevada 990-04-50-02-01, confirm the full-scale option (04 = 0-4 mils), system length (50 = 5.0 m), mounting option (02 = bulkhead), and agency approval (01 = CSA Div 2). Ensure your existing proximity probe is a 3300 NSv series. Power supply must provide 12-35 Vdc with adequate current. For additional support, contact PLC Source PRO (available at ubest101.myshopify.com) to verify that this exact model meets your machinery monitoring requirements.