Bently Nevada 330400-01-05 Accelerometer Acceleration Transducer

The Bently Nevada 330400-01-05 is a specialized configuration of the field‑proven 330400 piezoelectric accelerometer, specifically engineered for critical machinery monitoring in hazardous (classified) locations. This variant combines the standard ¼‑28 UNF integral mounting stud (suffix -01) with comprehensive intrinsic safety and explosion‑proof certifications (suffix -05), making it the preferred choice for installations in oil refineries, chemical plants, offshore platforms, and other explosive atmospheres where both reliable vibration measurement and regulatory compliance are mandatory.

The 330400 series itself is designed to meet American Petroleum Institute (API) Standard 670 requirements, ensuring accurate casing acceleration measurements for gear mesh monitoring, bearing health analysis, and general machine protection. The -05 option adds multiple international approvals – including ATEX, IECEx, and CSA – for use in Zone 0, Zone 1, Zone 2, and Class I/II Division 1/2 environments. This certification does not compromise the sensor’s core performance: it retains the full 50 g peak amplitude range, 100 mV/g sensitivity, 10 Hz to 15 kHz frequency response, and IP68‑rated hermetic sealing.

The 330400-01-05 is electrically identical to the non‑certified versions in terms of sensitivity, bias voltage, and noise floor, but it incorporates additional safety barriers and is approved for connection to intrinsically safe circuits with defined entity parameters (Ui = 28 V, Ii = 150 mA, Pi = 0.84 W, Ci = 10.8 nF, Li = 0 μH). Its case‑isolated design, rugged 316L stainless steel construction, and wide operating temperature range (-55°C to +121°C) ensure reliable performance in harsh environments while meeting strict safety standards.

This introduction focuses exclusively on the 330400-01-05 configuration, highlighting its unique hazardous‑area approvals, entity parameters, and installation requirements, and comparing it with other options (e.g., the non‑certified 330400-01-00 and the metric‑thread 330400-02-05) to guide proper selection for safety‑critical applications.

Functional Description and Certification Significance

The 330400-01-05 accelerometer operates on the same piezoelectric principle as the standard 330400: a piezoelectric element generates a charge proportional to acceleration, which is converted to a low‑impedance voltage signal with a sensitivity of 100 mV/g (10.2 mV/m/s²). However, the -05 variant has been rigorously tested and certified for use in potentially explosive atmospheres. It carries the Ex ia IIC T3 (ATEX/IECEx) marking for intrinsically safe equipment, allowing installation in Zone 0, Zone 1, and Zone 2 gas/vapor environments, as well as Class I, Division 1, Groups A, B, C, D and Class II, Groups E, F, G (CSA) for North American hazardous locations. It is also approved for Zone 22 (dust) with Ex tc IIC Dc and Class III for combustible dusts.

The -05 option is available only with the ¼‑28 UNF thread (not M8) at the time of this datasheet; for metric thread with approvals, consult the factory for custom options. The sensor’s entity parameters (Ui=28 V, Ii=150 mA, Pi=0.84 W, Ci=10.8 nF, Li=0 μH) define the maximum allowable electrical values that can be applied to the sensor without compromising intrinsic safety. These parameters are critical when selecting an associated intrinsically safe barrier or isolator.

The 330400-01-05 is also compliant with ABS (American Bureau of Shipping) for marine and offshore applications, making it suitable for floating production storage and offloading (FPSO) vessels, drilling rigs, and shipboard machinery monitoring. Its IP68 rating ensures watertight and dust‑tight protection for the sensor body, though cable connections require appropriate sealing for hazardous areas.

Detailed Comparison with Other Configurations

To aid in proper selection, the following table compares the 330400-01-05 with its primary alternatives (non‑certified versions and the higher‑range 330425 series). This highlights the unique value of the -05 for safety‑critical applications.

Selection Guide – Key Differences

The 330400-01-05 is the only fully certified version with the ¼‑28 UNF thread in the 330400 series. If you need metric thread and hazardous area approval, you would require a custom order (not offered as standard). For applications with expected vibration levels exceeding 50 g, the 330425-01-05 provides 75 g range but with lower sensitivity (25 mV/g) – a trade‑off that must be evaluated based on signal amplitude and noise requirements.

Hardware Characteristics – Specific to 330400-01-05

Physical Dimensions and Mounting

• Thread: ¼‑28 UNF integral stud (male). This standard thread is widely used in North America and compatible with many mounting bases and 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) – do not over‑tighten.

Connector and Cabling

• Connector: 3‑pin MIL‑C‑5015 receptacle (316L stainless steel). This connector is certified for use in hazardous areas when properly mated.

• Compatible Cables: For intrinsically safe installations, use cables that meet the entity parameter limitations and maintain the required cable parameters (type A or B per EN 60079‑25). Recommended cables: 130539 (18 AWG with fluorosilicone boot), 169253 (22 AWG), or 167103 (22 AWG armored) – all with 3‑socket plug and terminal lugs.

• Maximum Cable Length: 305 metres (1000 ft) – but must also satisfy capacitance and inductance limits for intrinsic safety (Ci and Li of the cable must be added to the sensor’s Ci and Li, and the total must not exceed the barrier’s limits).

• Mating Connector: 00531080 for custom cable assemblies.

Environmental and Electrical Specifications

The 330400-01-05 shares the same electrical and environmental performance as the standard 330400:

• 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 – essential for avoiding ground loops in hazardous installations.

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

• Shock Survivability: 5000 g peak.

• Humidity: 100% condensing (hermetically sealed).

• IP Rating: IP68 (sensor only).

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

Base Strain Sensitivity

• For serial numbers beginning with “G” (newer production): 0.005 g/mstrain – no mounting base required.

• For serial numbers NOT beginning with “G” (older units): 0.100 g/mstrain without mounting base, but reduces to 0.0005 g/mstrain when using the supplied Mounting Base (API adapter) – part number 37439-01 for ¼‑28 to ¼‑28. Bently Nevada recommends using the base for older units even in hazardous areas; the base itself is non‑incendive and can be installed in classified locations if properly grounded.

Intrinsic Safety and Hazardous Area Approvals – Detailed

The 330400-01-05 carries the following markings and certifications (as per the datasheet):

• ATEX:

  • Ex ia IIC T3 Ga (Zone 0/1)

  • Ex ec IIC Gc (Zone 2)

  • Ex tc IIC Dc (Zone 22)

  • IECEx: Ex ia IIC T3 Ga, Ex ec IIC Gc, Ex tc IIC Dc

• CSA:

  • Class I, Division 1, Groups A, B, C, D

  • Class II, Groups E, F, G

  • Class III

  • Class I, Division 2, Groups A, B, C, D

  • Class I Zone 2, AEx ec IIC Gc

  • Zone 22, AEx tc IIC Dc

Entity Parameters (for Zone 0/1 and Zone 2):

Conditions of Safe Use (ATEX/IECEx Zone 0/1):

• The sensor must be connected to an associated intrinsically safe apparatus that meets the above entity parameters.

• Cable type A or B (per EN 60079‑25) must be used, respecting cable capacitance and inductance limits.

• Operating ambient temperature: -55°C ≤ Tamb ≤ +121°C.

Conditions for Zone 2 (North America):

• The supply electrical parameters must not exceed the entity parameters.

• The mating connector must provide at least IP54 ingress protection (IEC 60079‑0 and IEC 60079‑7/15).

• Transient protection shall be provided, set at a level not exceeding 140% of the peak rated voltage at the supply terminals.

Requirements for North America (CSA):

• The sensor may only be powered by a power supply unit with a limited energy electric circuit per CAN/CSA C22.2 No. 61010‑1‑12 and ANSI/UL 61010‑1, or Class 2 as defined in the Canadian Electrical Code (C22.1, Section 16‑200) and/or National Electrical Code (NFPA 70), Article 725.121.

Installation Best Practices for 330400-01-05 in Hazardous Areas

1. Intrinsic Safety Barrier – Always connect the sensor through a certified intrinsic safety barrier or isolator that limits voltage, current, and power to within the entity parameters. Ensure the barrier’s output parameters do not exceed Ui, Ii, and Pi.

2. Cable Selection and Routing – Use cables with low capacitance and inductance to stay within the total allowable cable parameters. The sensor’s Ci (10.8 nF) and Li (0 μH) must be added to the cable’s capacitance and inductance; the total must not exceed the barrier’s limits. For long runs, use 18 AWG (130539) to reduce voltage drop.

3. Grounding – The case is isolated, so grounding is not required for the sensor body. However, the cable shield should be grounded at the power supply end (typically the barrier) to minimize noise. Do not ground the shield at both ends to avoid ground loops.

4. Connector Sealing – In hazardous areas, ensure the 3‑pin MIL connector is properly mated and sealed (IP54 or better) as required by ATEX/IECEx. Use appropriate cable glands and sealing compounds if needed.

5. Mounting Surface Preparation – Clean and lap the mounting surface to 32 µin rms or better. Apply anti‑seize compound if necessary, and torque the stud to 4.1 N·m (3.0 ft·lb). Do not use the connector body to apply torque.

6. Base Strain Sensitivity – If the sensor’s serial number does not begin with “G”, install the Mounting Base (37439-01) to reduce strain sensitivity. Ensure the base is properly torqued and grounded per site procedures.

7. Environmental Protection – Although the sensor is IP68, the cable termination and connectors require additional protection (splash boots, conduit, etc.) for outdoor or wet locations. The sensor itself is suitable for outdoor use when installed in a protected enclosure with wiring in conduit.

Comparison with Other Certified Options – Why Choose 330400-01-05?

• vs. 330400-01-00 – The -00 has no hazardous area approvals. If your plant has classified areas (Zone 0/1/2, Div 1/2), the -05 is mandatory. The -05 also adds ABS approval for marine use, which may be beneficial.

• vs. 330425-01-05 – Both have identical certifications and thread. The 330425 offers 75 g range and 25 mV/g sensitivity. Choose 330400 when higher sensitivity is required (100 mV/g) and vibration levels are ≤50 g. Choose 330425 when amplitudes exceed 50 g.

• vs. 330400-02-05 (if available) – Metric thread (M8 x 1) may be required for European or metric‑standard machinery. The -01 (¼‑28) is the standard North American option; if you need M8 with approvals, contact Bently Nevada for custom ordering.

Ordering Information

When ordering the 330400-01-05, use the full part number exactly as shown:

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

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

• -05 – Agency approval: Multiple (CSA, ATEX, IECEx)

Compatible Cables and Accessories for Hazardous Areas

Important: When ordering cables for hazardous areas, ensure the cable parameters (capacitance, inductance) do not exceed the allowable limits when combined with the sensor’s Ci and Li and the barrier’s specifications. Consult the barrier manufacturer’s documentation for cable length calculations.

Certifications and Compliance – Special Note

The 330400-01-05 is certified for intrinsic safety (Ex ia) and increased safety (Ex ec) and dust protection (Ex tc). It is suitable for use in Gas Groups IIC (hydrogen, acetylene) and IIB (ethylene) and IIA (propane). The temperature class T3 indicates a maximum surface temperature of 200°C under fault conditions, which is well above the sensor’s operating range.

The sensor is also RoHS compliant and meets China RoHS requirements with an EFUP of 15 years. For the most current approval certificates, refer to the Approvals Quick Reference Guide (108M1756) or visit bntechsupport.com.

Warranty and Support

Bently Nevada (Baker Hughes) provides a standard product warranty covering defects in materials and workmanship. For technical support, application engineering, or assistance with intrinsic safety calculations, contact your local Bently Nevada representative or access the Bently Nevada Media Library at bntechsupport.com.