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Brand: Bently Nevada
Bently Nevada 140734-01 3500/40M Proximitor Monitor
Description
Bently Nevada 140734-01 3500/40M Proximitor Monitor main board
The Bently Nevada 140734-01 is a 3500/40M Proximitor Monitor, the four-channel monitor in the 3500 machinery protection system that takes signals from proximity transducers (Proximitor systems) and turns them into radial vibration, thrust position, eccentricity, differential expansion or REBAM measurements. Each channel is compared with user-set alarm limits, and the 3500 rack acts on the result.
The part number 140734-01 is commonly listed for the 3500/40M main board. Seven Star LLC supplies it to plants in Oman and the GCC as a repair or expansion spare; the official 3500/40M datasheet lists a different spare number (176449-01) for the monitor, so compare the board label against the part number you hold before ordering.
140734-01 technical specifications
| Parameter | Specification |
|---|---|
| Manufacturer / part number | Bently Nevada 140734-01 (3500/40M Proximitor Monitor main board) |
| Channels | 4, programmed in pairs (channels 1-2 and 3-4) |
| Functions per channel pair | Radial vibration, thrust position, eccentricity, differential expansion, REBAM |
| Power consumption | 7.7 W typical |
| Input impedance | 10 kΩ |
| Radial vibration sensitivity | 3.94 mV/µm (100 mV/mil) or 7.87 mV/µm (200 mV/mil) |
| Differential expansion sensitivity | 0.394 mV/µm (10 mV/mil) or 0.787 mV/µm (20 mV/mil) |
| Accuracy (direct, gap, 1X, 2X) | Within ±0.33% of full scale typical, ±1% maximum |
| Direct filter (radial) | User-programmable, 4 Hz to 4000 Hz or 1 Hz to 600 Hz |
| Buffered transducer outputs | One coaxial connector per channel on the front panel, short-circuit protected, 550 Ω output impedance |
| Transducer power | -24 Vdc |
| Operating temperature | -30°C to +65°C with standard I/O; 0°C to +65°C with internal-barrier I/O |
| Storage temperature | -40°C to +85°C |
| Humidity | 95%, non-condensing |
| Main module size / weight | 241.3 x 24.4 x 241.8 mm (9.50 x 0.96 x 9.52 in) / 0.91 kg (2.0 lb) |
| I/O module size | 241.3 x 24.4 x 99.1 mm for non-barrier I/O modules |
| Alarms | Alert on each static value, Danger on any two; adjustable 0 to 100% of full scale |
Values are from the 3500/40M datasheet (141535 Rev. R). The rear I/O module fixes terminations, barriers and approvals.
How the 3500/40M monitors a machine
Channels are configured in pairs from the 3500 Rack Configuration software. A pair set to radial vibration returns direct amplitude, gap voltage, 1X and 2X amplitude and phase lag, Not-1X and Smax. A thrust pair returns direct and gap. Eccentricity pairs give peak-to-peak, gap, direct minimum and direct maximum. Filters can be tracked to running speed when a Keyphasor signal is present, which is why a 3500/25 Keyphasor module normally sits in the same rack.
Alert setpoints can be set for every static value, and Danger setpoints for any two of them. The monitor also provides time-delayed alarm logic and a bypass mode, and it feeds the rack through the backplane to the relay and communication modules. The module is a protection monitor, so firmware and configuration should be handled under your site change-control procedure.
Matching 140734-01 with 176449-01
Two numbers appear for the 3500/40M main board in the market: 140734-01 and 176449-01. The manufacturer datasheet names 176449-01 as the current monitor spare. A board carrying the 140734-01 label belongs to the same 3500/40M family and is used with the same rear I/O modules, but revision level and firmware can differ between old and new stock. Ask for the board label photograph and the revision letter before an install, and confirm that your 3500 configuration software version supports the firmware on the module.
Selection and ordering checklist for 140734-01
- Count the channels and functions: radial, thrust, eccentricity, differential expansion or REBAM, remembering that channels run in pairs.
- Confirm whether your spare is to match an existing 140734-01 board or to replace it with 176449-01.
- Ask for the PWA revision letter and firmware revision.
- Choose the rear I/O module: internal or external terminations, or internal barriers (125680-01, 126615-01, 135489-04 are listed in the datasheet).
- State the agency approval needed for the area classification.
- Check the 3500 rack software version supports the 3500/40M variant and firmware.
Installation, commissioning and maintenance
Insert the monitor in a full-height front slot with the matching I/O module in the rear. The 3500/40M supports hot-swap, but a replacement loads the rack configuration only after it has been written to the new module, so keep a saved configuration file for every rack. After insertion confirm the OK LED, check TX/RX, then verify gap voltage on each channel against the probe gap record. Use the front coaxial connectors to attach a portable analyser without disturbing the field wiring.
Calibrate and function-test according to the maintenance plan of the machine. Keep notes on the transducer scale factors entered, since a mismatch between configured and installed probe sensitivity is the most common source of wrong readings.
Typical applications in Oman and the GCC
The 3500/40M is found on centrifugal compressors, steam and gas turbines, pumps, motors and gearboxes in oil and gas, LNG, power generation, desalination and petrochemical plants. In the GCC climate the rack usually lives in an air-conditioned shelter, so the main field issues are probe cable routing, grounding and sealing of junction boxes against dust and humidity. Thrust and differential expansion channels are especially important on large turbines during hot starts.
3500/40M family at a glance
| Part number | Item |
|---|---|
| 176449-01 | 3500/40M Proximitor Monitor spare (datasheet spares list) |
| 140734-01 | 3500/40M main board, earlier-numbered listing |
| 125680-01 | Proximitor I/O module, internal terminations |
| 126615-01 | Proximitor I/O module, external terminations |
| 135489-04 | Proximitor I/O module with internal barriers, internal terminations |
| 3500/25 | Keyphasor module that supplies the speed reference |
Information to send with your RFQ
- Part number 140734-01, quantity and the rack slot position
- Existing monitor and I/O module part numbers and firmware revision
- Transducer types and sensitivities in use
- Required terminations, barriers and agency approval
- Delivery location in Oman or the GCC and condition required
Related Bently Nevada products: Bently Nevada 3500/42M Proximitor Seismic Monitor, Bently Nevada 125680-01 3500/40M Proximitor I/O Module, Bently Nevada 128240-01 3500/42M Prox/Seismic I/O Module, Bently Nevada 3500/46M Hydro Monitor, Bently Nevada 3500/72M Recip Rod Position Monitor and Bently Nevada 135489-04 3500/40M Proximitor Internal Barrier I/O.
Documents and quotation
The manufacturer datasheet for the 3500/40M Proximitor Monitor is attached on this page; read it together with your rack configuration and the site specification before confirming an order. The 3500/40M datasheet is attached here; it covers the family and lists 176449-01 for the monitor, so the part-number label should be matched on receipt.
Seven Star LLC is an independent supplier in Muscat serving Oman and the GCC. Stock position, lead time, condition and the certificates that travel with the shipment are confirmed in the written quotation.
Other Models in the 3500 40m Monitor Range
Seven Star LLC supplies models from the 3500 40m Monitor range in Oman and the GCC. Compare the related models below and request a quote for the one that matches your application.
| Model | Category | |
|---|---|---|
| Bently Nevada 140734-01 3500/40M Proximitor Monitor | Vibration Monitoring | You are viewing this model |
| Bently Nevada 176449-01 3500/40M Proximitor Monitor | Vibration Monitoring | View details |
Datasheets & Documents
- Datasheet Bently Nevada 3500/40M Proximitor Monitor Datasheet Download
Reviews (0)
About brand
Bently Nevada is the American machinery protection and condition monitoring brand behind the 3500 rack, the 3300 XL proximity probe and the System 1 software. It was founded in 1961 in Minden, Nevada, and is today a Baker Hughes business.
Seven Star LLC is an independent supplier in Muscat. We list Bently Nevada monitors, I/O modules, probes, proximitors, velocity transducers and transmitters for rotating equipment in Oman and the GCC, and source them by full part number.
Bently Nevada company profile
| Established | 1961, Minden, Nevada, USA, by Donald E. Bently. The business started earlier as Bently Scientific in Berkeley, California (1956). |
|---|---|
| Known for | The first commercial eddy-current proximity transducers for measuring shaft vibration and position on high-speed turbomachinery |
| Ownership | Acquired by GE Energy in 2002; part of Baker Hughes since GE Oil & Gas combined with Baker Hughes in 2017 |
| Rack generations | 5000 series (from 1965), 3300 series (from 1988), 3500 series (from 1995), Orbit 60 (current platform) |
| Product families | Machinery protection racks, proximity probes and proximitors, Keyphasor sensors, velocity and acceleration transducers, 2-wire vibration transmitters, general-purpose monitors, portable analyzers, wireless sensors and System 1 condition monitoring software |
| Typical machines | Steam and gas turbines, centrifugal and reciprocating compressors, pumps, motors, generators, fans and gearboxes |
Milestones
- 1956: Donald E. Bently starts Bently Scientific in Berkeley, California.
- 1961: The company moves to Minden, Nevada, as Bently Nevada.
- 1965: The 5000 series monitoring system is introduced.
- 1988: The 3300 series follows.
- 1995: The 3500 machinery protection system is launched.
- 2002 and 2017: GE Energy acquires Bently Nevada; it becomes part of Baker Hughes in 2017.
Bently Nevada product series
| Series | Type | What it does |
|---|---|---|
| 3500 | Machinery protection rack | Continuous online protection with alarm and danger relays. Modules include the 3500/15 power supply, 3500/20 rack interface, 3500/25 Keyphasor, 3500/42M proximitor/seismic, 3500/50 tachometer, 3500/60 temperature, 3500/33 relay and 3500/92 communication gateway |
| 3500 recip modules | Reciprocating compressor monitoring | 3500/70M impulse velocity, 3500/72M rod position and 3500/77M cylinder pressure |
| Orbit 60 | Protection and monitoring platform | The current Bently Nevada platform for protection, condition monitoring and data integration with System 1 |
| 3300 XL 8 mm | Proximity transducer system | Probe, extension cable and proximitor sensor for radial vibration, thrust position and Keyphasor reference on fluid-film bearing machines; also 5 mm and 25 mm versions |
| 330500 Velomitor, 190501 Velomitor CT | Piezo-velocity sensors | Casing velocity on rolling-element bearing machines and low-speed cooling tower fans |
| 990 and 991 | 2-wire transmitters | 4-20 mA vibration (990) and thrust position (991) signals straight into a PLC or DCS, without a monitor rack |
| 1900/65A, 2300 | Compact monitors | Protection for balance-of-plant pumps, fans and motors where a full 3500 rack is not justified |
A proximity probe measures the gap to the shaft, so it sees shaft movement inside a fluid-film bearing directly. A velocity or acceleration sensor sits on the casing and suits rolling-element bearing machines. Critical turbomachinery usually carries two X-Y probes per bearing, two axial probes for thrust position and a Keyphasor probe for speed and phase.
Where Bently Nevada systems are used
In Oman and the GCC, Bently Nevada racks and probes protect gas turbines, compressors and steam turbines in gas processing, LNG, refining, petrochemical, power and desalination plants. Many installations are 3500 racks that have run for years, so most requests are for like-for-like module, probe, extension cable and proximitor replacements, plus upgrades to newer monitors.
Ordering and replacement: what we need
For probes and proximitors, send the full part number with all option digits (for example 330101-00-27-10-02-05). The digits set the probe length, cable length, connector and approvals, and the probe, cable and proximitor must match in total system length. For 3500 modules, send the module and I/O part numbers from the rack and say whether the I/O is internal or external termination, or barrier type. If a module is obsolete, we quote the replacement that Bently Nevada names and point out any configuration or firmware change.
Facts checked against Baker Hughes Bently Nevada pages and published company history, October 2026.
Browse Bently Nevada products by category: Vibration.
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Frequently Asked Questions
What does the 3500/40M monitor measure?
It accepts proximity transducer inputs and can be programmed for radial vibration, thrust position, eccentricity, differential expansion or REBAM. Channels are configured in pairs.
Does the 140734-01 include the I/O module?
No. The monitor is a front module. A separate rear I/O module sets internal or external terminations or internal barriers.
How many channels does it have?
Four. Channels 1 and 2 form one pair and channels 3 and 4 the other, and each pair can perform up to two functions in total.
What is its operating temperature range?
-30°C to +65°C with standard I/O modules, and 0°C to +65°C with the internal barrier I/O module with internal terminations.
What other module is needed for speed-related measurements?
A Keyphasor module such as the 3500/25 supplies the speed reference used for 1X vector measurements and tracking filters.
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