Description
The Bently Nevada 990-04-XX-01-CN is a 2-wire, loop-powered vibration transmitter from the 990 series, designed for original equipment manufacturers (OEMs) of centrifugal air compressors, small pumps, motors, and fans. This integrated transmitter accepts input from a 3300 NSv proximity probe and provides a proportional 4-20 mA output signal representing peak-to-peak vibration amplitude for direct connection to PLC, DCS, or SCADA control systems.
Application Scenarios
In a centrifugal air compressor package, space constraints around the rotor bearing housing often preclude installation of traditional proximity probe systems with separate Proximitor sensor modules and lengthy cable runs. The 990-04-XX-01-CN addresses this challenge directly: its integrated Proximitor sensor eliminates the need for an external signal conditioning unit, while its compact potted construction enables mounting in tight locations with minimal clearance. When a loose probe connector generates a false high-vibration signal, the transmitter’s Not OK/Signal Defeat circuit immediately drives the output below 3.6 mA within 100 microseconds, allowing the control system to distinguish between a genuine machinery fault and sensor failure—preventing unnecessary trips while maintaining protection integrity.
Parameter
| Parameter | Value/Description |
|---|---|
| Product Model | 990-04-XX-01-CN |
| Manufacturer | Bently Nevada (Baker Hughes / GE) |
| Product Category | 2-Wire Loop-Powered Vibration Transmitter |
| Compatible Probe | 3300 NSv Proximity Probe + Extension Cable |
| Full-Scale Range | 0 to 4 mils pp (0 to 100 µm pp) |
| System Length (XX) | 50 = 5.0 m, 70 = 7.0 m |
| Mounting Option (01) | 35 mm DIN Rail Clips |
| Approval Option (CN) | China Market Certification |
| Output Signal | 4-20 mA DC, 2-wire loop-powered |
| Supply Voltage | +12 to +35 VDC |
| Loop Accuracy | ±1.5% of full-scale range |
| Frequency Response | 5 Hz to 6,000 Hz (+0, -3 dB) |
| Maximum Loop Resistance | 1,000 Ω at 35 VDC |
| Probe Gap Range | 0.5 to 1.75 mm (20 to 55 mils) |
| Operating Temperature | -30°C to +100°C |
| Enclosure Rating | IP66 / NEMA 4X, potted construction |
| Dimensions | Approx. 7.3 × 6 × 10 cm |
| Weight | Approx. 280 g – 460 g |