Bently Nevada 330400 Accelerometer Acceleration Transducer

Overview

The Bently Nevada 330400 is a casing-mounted acceleration transducer for critical machinery, intended for applications where acceleration is the right measurement, such as gear mesh monitoring on high-speed gearboxes and compressor trains. It is designed to address the requirements of American Petroleum Institute Standard 670 for accelerometers, with an amplitude range of 50 g peak and a sensitivity of 100 mV/g. The Bently Nevada 330400 is powered directly by the monitor, with its electronics inside a hermetically sealed 316L stainless steel case.

Seven Star LLC supplies the Bently Nevada 330400 on request to rotating equipment and reliability teams in the Sultanate of Oman and the wider GCC, with engineering support in Muscat. The Bently Nevada 330400 datasheet (document 141638, shared with the 330425) is attached to this page, and our team can confirm the stud thread, approval option, interconnect cable and mounting base needed for each measurement point.

Operating Principle

The Bently Nevada 330400 works on the piezoelectric principle: casing acceleration produces a proportional charge in the sensing element, and electronics inside the sealed case convert that charge into a low-impedance voltage of 10.2 mV per m/s² (100 mV/g) ±5%. The transducer is powered from a −24 V dc supply at a nominal bias current of 2 mA and sits at an output bias voltage of −8.5 V dc ±0.5 V dc, the same powering arrangement used by Bently Nevada monitors for proximity and seismic inputs.

The frequency response is 10 Hz to 15 kHz (600 to 900,000 cpm) within ±3 dB and 30 Hz to 10 kHz within ±10%, while the mounted resonant frequency is above 30 kHz. That bandwidth is why the Bently Nevada 330400 is the sensor of choice for gear mesh frequencies, blade pass and rolling-element bearing defect frequencies, which sit well above the range a velocity sensor handles comfortably. Amplitude linearity is ±1% up to 490 m/s² (50 g) peak and the broadband noise floor is 0.039 m/s² (0.004 g) rms between 10 Hz and 15 kHz, so the sensor can resolve both low-level early bearing signals and high gear mesh amplitudes.

Engineering Design of the Bently Nevada 330400

The Bently Nevada 330400 body is 23 mm (0.93 in) in diameter and 59 mm (2.3 in) high including the mounting stud, weighs about 100 g (3.5 oz) without cable and is made from 316L stainless steel. The case is hermetically sealed, equivalent to IP68 for the sensor itself, and electrically isolated from the internal circuit. Connection is through a 3-pin MIL-C-5015 receptacle, and the integral stud is ordered as either 1/4-28 UNF or M8 x 1. The datasheet calls for a mounting surface finish of 32 µin rms and a mounting torque of 4.1 N·m (3.0 ft·lb), and the sensor works in any orientation.

The Bently Nevada 330400 operates and can be stored from −55 °C to +121 °C, survives shocks up to 5,000 g peak and tolerates 100% condensing humidity. Signal cables can run up to 305 m (1,000 ft) to the monitor with no degradation of signal. Base strain sensitivity is a practical concern on thin or flexing casings; units with serial numbers starting with “G” have a base strain sensitivity of 49 mm/s²/µstrain (0.005 g/µstrain), and the 37439 mounting bases (1/4-28 or M8) reduce base strain further for older units. The 43217 accelerometer mounting kit is offered where the sensor must be installed inside a housing.

Key Features

The Bently Nevada 330400 combines API 670 performance with a compact stainless steel package. Its main capabilities include:

• Designed to address the API 670 requirements for accelerometers used in machinery protection systems.
• Sensitivity of 10.2 mV/m/s² (100 mV/g) ±5% with a 490 m/s² (50 g) peak amplitude range and ±1% linearity.
• Wide frequency response from 10 Hz to 15 kHz (±3 dB) for gear mesh, blade pass and bearing defect frequencies.
• Mounted resonant frequency above 30 kHz and transverse sensitivity below 5% of axial.
• Hermetically sealed 316L stainless steel case, equivalent to IP68 for the sensor, with case isolation.
• Integral 1/4-28 UNF or M8 x 1 mounting stud and a 3-pin MIL-C-5015 connector.
• Operating range of −55 °C to +121 °C and shock survivability of 5,000 g peak.
• Approval option covering CSA, ATEX and IECEx, including Ex ia IIC T3 Ga intrinsically safe and Ex ec IIC Gc ratings, plus ABS marine type approval.

Industrial Applications

In Oman and the GCC the Bently Nevada 330400 is typically found on integrally geared centrifugal compressors for instrument and process air, speed-increasing gearboxes between gas turbines and generators, gas compression trains in the interior oil and gas fields, LNG and refinery machinery in Sur, Sohar and Duqm, and large pump and fan gearboxes at power and desalination plants. On these machines proximity probes cover shaft vibration in fluid-film bearings, while the Bently Nevada 330400 adds the high-frequency casing measurement that reveals gear tooth wear, mesh problems and rolling-element bearing damage.

The accelerometer connects to rack monitors such as the Bently Nevada 3500/42M Proximitor Seismic Monitor, which accepts acceleration inputs and can integrate them to velocity, or to the Bently Nevada 1900/65A general purpose equipment monitor for balance-of-plant machines. Where velocity is the preferred parameter, the Bently Nevada 330500 Velomitor piezo-velocity sensor is the alternative in the same family. Seven Star LLC helps engineers in Muscat and across the GCC choose the stud thread, cable type and mounting base for each accelerometer point and plan spare sensors for turnarounds.

Technical Specifications

Key parameters of the Bently Nevada 330400, taken from manufacturer datasheet 141638 Rev. AB (specified at +20 to +30 °C and 100 Hz unless noted):

Request a Quote for Bently Nevada 330400

To request a quotation for the Bently Nevada 330400, check current availability and lead time or download the manufacturer datasheet from the document tab on this page, send the order code or the stud thread, approval option, cable type and length to the Seven Star LLC instrumentation team. We supply the Bently Nevada 330400 with its cables, mating connectors and mounting bases to customers in Oman and the GCC.

Related Bently Nevada sensor from Seven Star LLC: Bently Nevada 190501 Velomitor CT velocity transducer.