Description
Bently 330525-00
Technical Specifications
| Parameter Category | Specific Specification |
|---|---|
| Manufacturer | Bently Nevada (Baker Hughes) |
| Product Family | Velomitor XA Piezo-Velocity Sensor |
| Agency Approval | 00 = None required |
| Sensitivity | 3.94 mV/mm/s (100 mV/in/s) ±5% |
| Frequency Response | 4.5 to 2,000 Hz (270 to 120,000 cpm) ±3.0 dB; 6.0 to 1,000 Hz (360 to 60,000 cpm) ±0.9 dB |
| Velocity Range | 1,270 mm/s (50 in/s) peak |
| Transverse Sensitivity | Less than 5% of sensitivity |
| Amplitude Linearity | ±2% to 152 mm/s (6 in/s) peak |
| Mounted Resonant Frequency | Greater than 12 kHz |
| Broadband Noise Floor (4.5 Hz to 2 kHz) | 0.004 mm/s (160 min/s) rms, nominal |
| Temperature Sensitivity | -14% to +7.5% over operating temperature range |
| Power Requirements | DC Voltage: -22 to -30 VDC; Bias Current: 2.5 to 6.0 mA |
| Output Bias Voltage | -12 ± 3.0 VDC, over temperature referenced to dynamic output |
| Output Impedance | Less than 2,400 ohms |
| Case Isolation | Case isolated from internal electronics |
| Maximum Cable Length | 305 meters (1,000 feet) |
| Operating Temperature | -55°C to +121°C (-67°F to +250°F) |
| Storage Temperature | -55°C to +150°C (-67°F to +302°F) |
| Case Material | 316L stainless steel |
| Connector | 2-pin Mil-C-26482, hermetically sealed, 316L stainless steel shell |
| Mounting Thread | 1/4 inch NPT (taper pipe thread) |
| Physical Dimensions | Diameter: 28 mm (1.1 in); Height: 73.1 mm (2.88 in) |
| Weight | 156 g (5.5 oz) typical |
| Environmental Rating | IP-65 and NEMA 4X when properly installed with mating extension cable |
Key Features
- Ruggedized Construction: 316L stainless steel case provides excellent corrosion resistance for harsh environments
- Weatherproof Design: Unique weatherproof connector and cable assembly permits mounting without a protective housing
- Internal Integration: Built-in piezoelectric accelerometer with internal electronic integration provides velocity output directly
- Wide Frequency Response: 4.5 Hz to 2,000 Hz covers most rotating machinery vibration frequencies
- Low Noise Floor: 0.004 mm/s broadband noise floor enables detection of very low vibration levels
- High Shock Survival: 5,000 g peak shock survival rating
- Case Isolation: Case is electrically isolated from internal electronics, preventing ground loop problems
- Long Cable Capability: Up to 305 meters (1,000 feet) cable length without signal degradation
Application Scenarios
- Bearing housing vibration monitoring: Measures absolute vibration velocity on bearing housings of pumps, motors, compressors, and turbines
- Gearbox condition monitoring: Monitors gearbox casing vibration for gear mesh and bearing faults
- Fan and blower monitoring: Measures casing vibration on industrial fans and blowers
- Cooling tower monitoring: Monitors gearbox and fan vibration in cooling tower applications
- Paper machine monitoring: Measures roll bearing vibration in paper manufacturing
- Food processing equipment: Stainless steel construction suitable for washdown environments
- Marine applications: Corrosion-resistant 316L case suitable for saltwater environments
- Outdoor installations: Weatherproof design eliminates need for protective enclosures
Performance Parameters The sensor provides a sensitivity of 3.94 mV/mm/s (100 mV/in/s) with ±5% tolerance. The frequency response of 4.5 to 2,000 Hz (±3.0 dB) captures a wide range of machinery fault frequencies. The 6.0 to 1,000 Hz range provides ±0.9 dB accuracy for the most common vibration frequencies. The velocity range of 1,270 mm/s (50 in/s) peak accommodates very high vibration levels. The transverse sensitivity of less than 5% ensures accurate measurement even with some misalignment. The amplitude linearity of ±2% to 152 mm/s (6 in/s) peak provides accurate readings across typical operating ranges.
Material Composition The case is constructed from 316L stainless steel, providing superior corrosion resistance compared to standard 304 stainless steel. The internal piezoelectric sensing element is a high-stability ceramic material. The internal electronics include charge amplifier, integrator, and output driver circuits. The connector is hermetically sealed with a 316L stainless steel shell. The cable assembly (when ordered) uses fluoropolymer insulated conductors with a rugged outer jacket.
Structural Characteristics The sensor has a cylindrical 316L stainless steel case with a 1/4 inch NPT mounting thread on the base. The height is 73.1 mm (2.88 in) with a diameter of 28 mm (1.1 in). The 2-pin Mil-C-26482 connector is located on the top of the case. The connector is hermetically sealed to prevent moisture ingress. The internal construction includes the piezoelectric element, signal conditioning electronics, and output driver, all encapsulated for environmental protection.
Working Principle The sensor contains a piezoelectric accelerometer that generates a charge proportional to acceleration when subjected to vibration. This charge signal is converted to a voltage by an internal charge amplifier. The voltage is then integrated by an internal electronic integrator to produce a velocity signal. The output is a DC-biased AC voltage proportional to vibration velocity, with a sensitivity of 3.94 mV per mm/s of vibration velocity. The -22 to -30 VDC power supply provides excitation for the internal electronics through a constant current diode. The output bias voltage of -12 VDC indicates proper sensor operation.
