Bently Nevada 330525-05 Velomitor Sensor Overview

The Bently Nevada 330525-05 is a Velomitor XA piezo-velocity sensor. It measures absolute vibration velocity on rotating machinery. This sensor requires no external signal conditioning for velocity measurements. The 330525-05 uses agency approval option 02 for SIRA/CENELOC certifications. Sensitivity is 3.94 mV/mm/s (100 mV/in/s) ±5% for direct velocity output. As a result, it interfaces easily with standard monitoring systems. The case is hermetically sealed for harsh environment protection.

Frequency Response & Performance

The Bently Nevada 330525-05 delivers exceptional frequency response characteristics. Frequency response spans 4.5 to 2,000 Hz (270 to 120,000 cpm) at ±3.0 dB. Moreover, tighter response of 6.0 to 1,000 Hz (360 to 60,000 cpm) at ±0.9 dB is available. Mounted resonant frequency exceeds 12 kHz for high-frequency measurement capability. Temperature sensitivity ranges from -14% to +7.5% typical over the operating range. Amplitude linearity reaches ±2% to 152 mm/s (6 in/s) peak. Therefore, the 330525-05 provides accurate measurements across most industrial machinery speeds.

Now consider the noise and range specifications. Velocity range reaches 1270 mm/s (50 in/s) peak for high-amplitude applications. Transverse sensitivity is less than 5% of sensitivity for minimal cross-axis error. Broadband noise floor measures only 0.004 mm/s (160 µin/s) rms nominal. This low noise floor allows detection of very small vibration changes.

Electrical Specifications

The Bently Nevada 330525-05 requires specific power conditions for proper operation. DC voltage range is -22 to -30 VDC for the power supply. Bias current must stay between 2.5 to 6.0 mA for correct sensor function. Output bias voltage measures -12 ± 3.0 VDC over temperature referenced to pin A. Dynamic output impedance is less than 2400 Ω for signal transmission. Maximum cable length reaches 305 metres (1,000 feet) of BN part number 02173007 cable. Consequently, no signal degradation occurs at this maximum length. Polarity notes that pin A goes positive with respect to pin B when sensor case motion is toward the connector.

Environmental & Mechanical Specifications

The Bently Nevada 330525-05 operates in extreme environmental conditions. Operating temperature range spans -55°C to +121°C (-67°F to +250°F) . Shock survivability reaches 5000 g peak maximum for rugged durability. Relative humidity tolerance goes to 100% non-submerged conditions. The hermetically sealed case protects internal components completely. Magnetic field susceptibility is less than 51 µin/s/gauss at 50 gauss, 50-60 Hz. This low susceptibility ensures reliable operation near motors and generators.

Now examine the mechanical construction details. Weight is 156 g (5.5 oz) typical for easy mounting. Diameter measures 28 mm (1.1 in) for standard installation footprints. Height is 73.1 mm (2.88 in) including the connector. Case material is 316L stainless steel for excellent corrosion resistance. Connector is 2-pin Mil-C-26482 hermetically sealed with 316L stainless steel shell. Mounting torque should not exceed 45 N-m (33 ft-lb) . Cable bend radius minimum is 1.5 inches for cable protection.

Hazardous Area Approvals

The Bently Nevada 330525-05 carries multiple hazardous area certifications. Intrinsic safety approvals include Ex ia IIC T4 and AEx ia IIC T4. These apply for Class I, Division 1, Groups A, B, C and D. Additionally, Class II, Groups E, F, G and Class III are approved. Temperature rating is T4 @ -40°C ≤ Ta ≤ 100°C for safe operation.

Non-incendive approvals are also available for this sensor. These include Ex nL IIC T4 and AEx nA IIC T4. Class I, Division 2, Groups A, B, C, D are covered under this approval. Install per drawing 167539 for proper hazardous area compliance. Temperature rating remains T4 @ -40°C ≤ Ta ≤ 100°C for Division 2 installations.

Key Features & Benefits

• Direct velocity output – The 330525-05 requires no external integrator for velocity measurements.

• Wide frequency response – Covers 4.5 Hz to 2 kHz for comprehensive machinery monitoring.

• Hermetically sealed case – 316L stainless steel construction protects against moisture and contaminants.

• Hazardous area approved – Ex ia IIC T4 and Class I, Division 1 certifications included.

• Low noise floor – Only 0.004 mm/s rms for detecting small vibration changes.

• Wide temperature range – Operates reliably from -55°C to +121°C.

Installation Guidelines

Follow these steps to install the Bently Nevada 330525-05 correctly. First, clean the mounting surface thoroughly before sensor placement. Second, apply a thin layer of coupling grease to the sensor base. Third, thread the sensor into the mounting hole by hand initially. Fourth, tighten the sensor to 45 N-m (33 ft-lb) maximum torque. Do not exceed this value to avoid damage. Fifth, connect the 2-pin Mil-C-26482 connector until fully seated. Finally, verify the output bias voltage reads -12 ± 3.0 VDC at pin A.

Use BN part number 02173007 cable for lengths up to 305 metres. Maintain minimum bend radius of 1.5 inches for all cable routing. Also, avoid running sensor cables parallel to high voltage power lines. The 330525-05 case is electrically isolated from the measurement circuit.

Package Contents

Your shipment includes the following items:

• 1 x Bently Nevada 330525-05 Velomitor XA Piezo-velocity Sensor

• 1 x Installation manual with wiring diagram and specifications

• 2 x Mounting studs for different thread requirements

• 1 x Calibration certificate with individual sensor data

No interconnecting cable is included with the 330525-05. Therefore, you must order BN part number 02173007 separately. Likewise, no mounting hardware beyond the studs is provided.

Frequently Asked Questions (FAQ)

1. What is the difference between Velomitor and accelerometer sensors?
The Bently Nevada 330525-05 outputs velocity directly without integration. Accelerometers require integration to obtain velocity, which amplifies low frequency noise.

2. Can this sensor be used in submerged applications?
No. The 330525-05 is rated for 100% non-submerged humidity only. Full submersion will damage the sensor despite the hermetic seal.

3. What is the maximum cable length for this sensor?
The 330525-05 supports up to 305 metres (1,000 feet) of BN 02173007 cable. No signal degradation occurs at this maximum length.

4. Is the sensor case grounded or isolated?
The 330525-05 features a case isolated design. Therefore, grounding does not affect the measurement signal quality.

5. What machinery is this sensor typically used on?
The 330525-05 is ideal for turbines, compressors, pumps, fans, and motors. Its wide frequency response covers most industrial rotating equipment.

Why Choose the Bently Nevada 330525-05?

This Velomitor XA sensor delivers reliable absolute vibration measurements for critical machinery. For starters, the Bently Nevada 330525-05 outputs velocity directly without external conditioning. Its sensitivity of 100 mV/in/s matches standard monitoring system inputs. The frequency response from 4.5 Hz to 2 kHz covers most machinery fault frequencies. Furthermore, the hermetically sealed 316L stainless steel case withstands harsh environments. Operating temperatures from -55°C to +121°C suit both outdoor and high-temperature applications. Multiple hazardous area approvals allow installation in Division 1 and 2 locations. The low noise floor of 0.004 mm/s enables detection of small vibration changes. Most importantly, the 330525-05 requires no power supply beyond a simple -24 VDC bias.

Order the Bently Nevada 330525-05 today for your absolute vibration monitoring needs. This sensor is perfect for steam turbines, gas turbines, centrifugal compressors, and large pumps in hazardous areas.