Bently Nevada 330400-01-00 Accelerometer Acceleration Transducer

The Bently Nevada 330400-01-00 is a specific configuration of the high‑performance 330400 piezoelectric accelerometer, engineered for critical machinery monitoring applications that demand precise casing acceleration measurements. This particular variant (suffix -01-00) is equipped with a ¼‑28 UNF integral mounting stud and carries no agency approvals (non‑hazardous area version). It is the standard, cost‑effective choice for installations where explosive atmospheres are not a concern and where the widely used ¼‑28 UNF thread is preferred.

The 330400 series is designed to meet American Petroleum Institute (API) Standard 670 requirements for accelerometers, making it a trusted solution for gear mesh monitoring, bearing health assessment, and general machine vibration analysis in oil and gas, power generation, and heavy industry. The -01-00 variant delivers the same core performance: 50 g peak amplitude range, 100 mV/g sensitivity, broad frequency response from 10 Hz to 15 kHz, and rugged IP68‑rated construction for harsh environments. Its case‑isolated design eliminates ground loops, and the integral stud ensures a secure, low‑loss mechanical coupling.

This introduction focuses on the 330400-01-00 configuration, highlighting its unique features and comparing it with other available options (e.g., the 330400-02-00 with M8 stud, and the 330425 series with higher g‑range and lower sensitivity). By understanding these differences, you can select the optimal transducer for your specific machinery protection needs.

Functional Description and Application Focus

The 330400-01-00 accelerometer operates on the piezoelectric principle, converting mechanical acceleration into an electrical charge that is conditioned into a low‑impedance voltage signal. Its sensitivity of 100 mV/g (10.2 mV/m/s²) provides a strong, noise‑resistant output for general‑purpose vibration monitoring. The ¼‑28 UNF stud is a de facto standard in North America, compatible with most mounting bases, adapter kits, and existing installations. This makes the -01-00 an ideal drop‑in replacement or new installation choice for facilities that have standardized on this thread.

The transducer is optimized for casing‑mounted measurements on bearing housings, compressor cases, turbine shells, and gearboxes. It excels at detecting high‑frequency phenomena such as gear mesh frequencies, blade pass vibrations, and bearing defect signatures—where its ±3 dB response up to 15 kHz and ±10% response up to 10 kHz provide reliable data. The low noise floor (0.004 g rms) ensures that small amplitude signals are not masked, enabling early fault detection.

Unlike the 330425 variant, which offers 75 g range and 25 mV/g sensitivity for higher‑amplitude applications, the 330400-01-00 is tailored for moderate vibration levels (up to 50 g peak) with superior signal‑to‑noise ratio due to its higher sensitivity. The -01-00 does not include hazardous area approvals, making it lighter and slightly less expensive than the -05 version (which carries multiple certifications). This trade‑off is acceptable for installations in safe (non‑classified) areas.

Detailed Comparison with Other Configurations

To assist in proper selection, the following table compares the 330400-01-00 with its main alternatives within the 330400 family and with the 330425 series.

Selection Guide – Key Differences

The -01-00 stands out as the most common and economical choice for safe areas with ¼‑28 UNF mounting. If you require metric threads, choose -02-00; if you need hazardous area approvals, choose -01-05 (or -02-05). For higher acceleration ranges (up to 75 g), the 330425 series provides lower sensitivity (25 mV/g) but is otherwise mechanically and electrically similar.

Hardware Characteristics – Specific to 330400-01-00

Physical Dimensions and Mounting

• Thread: ¼‑28 UNF integral stud (male). This thread mates directly with standard ¼‑28 mounting holes or adapters.

• Height: 59 mm (2.3 in) including stud.

• Diameter: 23 mm (0.93 in).

• Weight: 99 g (3.5 oz) typical (no cable).

• Mounting Surface Finish: Recommended 32 µin rms or better.

• Mounting Torque: 4.1 N·m (3.0 ft·lb). Over‑tightening can damage the stud or housing.

Connector and Cabling

• Connector: 3‑pin MIL‑C‑5015 receptacle (316L stainless steel). This is the industry‑standard connector for these accelerometers.

• Compatible Cables:

  • 130539: 18 AWG, 3‑conductor shielded, with fluorosilicone boot.

  • 169253: 22 AWG, 3‑conductor shielded.

  • 167103: 22 AWG, armored.

• Maximum Cable Length: 305 metres (1000 ft) without signal degradation.

• Mating Connector: 00531080 (for custom cable assembly).

Environmental and Electrical Specifications

The 330400-01-00 shares identical electrical and environmental performance with all 330400 variants:

• Power: -24 V dc ±0.5 V, 2 mA nominal bias current.

• Output Bias Voltage: -8.5 V dc ±0.5 V.

• Grounding: Case isolated (the housing is electrically isolated from the mounting stud to prevent ground loops).

• Operating/Storage Temperature: -55°C to +121°C (-67°F to +250°F).

• Shock Survivability: 5000 g peak.

• Humidity: 100% condensing (hermetically sealed case).

• IP Rating: IP68 (sensor only) – dust tight and watertight.

• Magnetic Field Susceptibility: < 225 mg/gauss at 50 gauss, 50‑60 Hz.

Base Strain Sensitivity Notes

Base strain sensitivity can affect low‑frequency measurements if the mounting surface flexes. For the 330400-01-00:

• If the serial number begins with “G” (newer sensors): Base strain sensitivity is only 0.005 g/mstrain – no extra mounting base required.

• If the serial number does NOT begin with “G” (older, pre‑April 2004): Base strain sensitivity is 0.100 g/mstrain without the mounting base, but reduces to 0.0005 g/mstrain when using the supplied Mounting Base (API adapter) – part numbers 37439-01 (¼‑28 to ¼‑28) or 37439-02 (M8 to M8). Bently Nevada recommends using the base for these older units.

Installation Best Practices for 330400-01-00

To achieve accurate, repeatable measurements with the 330400-01-00:

1. Surface Preparation – Clean the mounting surface to remove paint, rust, or debris. Achieve a surface finish of 32 µin rms or better (e.g., by lapping). This ensures proper mechanical coupling and frequency response.

2. Stud Installation – Apply a thin layer of anti‑seize compound (if required) and hand‑tighten the integral stud into the prepared hole. Then torque to 4.1 N·m (3.0 ft·lb). Do not use the connector housing to apply torque; use a wrench on the hex flats of the stud.

3. Cable Connection – Align the 3‑pin connector and tighten the coupling nut securely. For long cable runs, use the recommended 18 AWG cable (130539) to minimise voltage drop and signal loss. Route cables away from high‑voltage lines and avoid sharp bends.

4. Grounding – Because the case is isolated, the sensor does not require a separate ground. However, the cable shield should be connected to the monitoring system’s common reference at the power supply end to minimize electrical noise.

5. Base Strain Consideration – If the sensor’s serial number does not begin with “G”, install the supplied Mounting Base (37439-01 for ¼‑28) between the stud and the machine surface. This reduces base strain sensitivity dramatically.

6. Environmental Protection – For outdoor installations, use splash boots (available separately) and ensure all cable connections are sealed. The sensor itself is IP68, but the cable termination may require additional protection.

Comparison with 330425-01-00 – When to Choose Which?

The 330425 series is the higher‑range sibling of the 330400. The -01-00 configuration of the 330425 would have the same thread and no approvals, but differs in:

• Sensitivity: 25 mV/g (vs. 100 mV/g)

• Range: 75 g peak (vs. 50 g)

• Noise: Higher noise floor proportionally, but still adequate for most machinery.

Choose 330400-01-00 when:

• Expected vibration levels are below 50 g peak.

• Higher sensitivity (100 mV/g) is needed to detect low‑amplitude signals (e.g., bearing early faults).

• You want better signal‑to‑noise ratio and lower noise floor.

Choose 330425-01-00 when:

• Vibration levels may exceed 50 g (e.g., high‑speed gearboxes, some reciprocating machines).

• The lower sensitivity is acceptable because signals are strong.

Both share the same mechanical dimensions, connector, temperature range, and mounting torque, so they are interchangeable mechanically.

Certifications and Compliance for 330400-01-00

Because the -00 option has no hazardous area approvals, it is certified for general industrial use only. It complies with:

• FCC Part 15 – Radio frequency interference limits.

• EMC Directive 2014/30/EU – Electromagnetic compatibility.

• RoHS Directive 2011/65/EU – Restriction of hazardous substances.

• China RoHS – EFUP of 15 years (SJ/T 11364-2024).

• ABS – (Marine Vessels, Offshore Units) – the sensor itself is approved for maritime use even without explosion protection.

It is NOT rated for ATEX, IECEx, or CSA Class I/II hazardous locations. If your installation requires intrinsic safety or explosion-proof certification, you must order the -05 option (e.g., 330400-01-05).

Ordering Information

When ordering the 330400-01-00, use the full part number exactly as shown. The numbering convention is:

• 330400 – Base model (accelerometer, 50 g, 100 mV/g)

• -01 – Mounting thread: ¼‑28 UNF integral stud

• -00 – Agency approval: None

Compatible Cables and Accessories

Note: The 330400-01-00 does not include a cable; order separately. Ensure cable length does not exceed 305 m.

Warranty and Support

The Bently Nevada 330400-01-00 is covered under the standard manufacturer’s warranty (refer to Bently Nevada Terms and Conditions). For technical support, application assistance, or custom cable configurations, contact your local Bently Nevada sales representative or access the Bently Nevada Media Library at bntechsupport.com.