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Brand: Bently Nevada
Bently Nevada 125840-01 3500/15 HV AC Power Input Module
Description
Bently Nevada 125840-01 high voltage AC power input module for 3500/15 legacy supplies
The Bently Nevada 125840-01 is the High Voltage AC Power Input Module (PIM) of the legacy 3500/15 power supply. It is the small half-height module that sits behind the power supply in the rear of the 3500 rack, takes the incoming mains cable, holds the input fuse and passes filtered power to the supply module in front. The high-voltage type is for 220 V nominal systems, which covers most mains networks in Oman and the GCC.
The manufacturer’s legacy 3500/15 datasheet lists 125840-01 as the High Voltage ac PIM and 125840-02 as its Low Voltage ac (110 V nominal) counterpart. The partner supply module is 127610-01. Seven Star LLC supplies 125840-01 in Oman and the GCC as an independent supplier in Muscat.
Which 3500/15 generation does 125840-01 belong to?
Two generations of 3500/15 power input modules exist. The current manufacturer datasheet (141530) describes a Universal AC supply that accepts 85 to 264 Vac rms and states plainly that the Universal AC supply and PIM are not compatible with the legacy 3500 AC power supply, High Voltage AC PIM and Low Voltage AC PIM. 125840-01 is one of those legacy items, so it is a like-for-like spare only for racks that still carry the older AC supply. It should not be fitted with a Universal AC power supply, nor should the Universal PIM (106M1081-01) be fitted to an older supply.
125840-01 technical specifications
| Parameter | Specification |
|---|---|
| Manufacturer / part number | Bently Nevada (Baker Hughes, formerly GE) / 125840-01 |
| Description | High Voltage ac power input module (PIM) for the 3500/15 power supply |
| Nominal voltage | 220 V nominal |
| Input voltage range | 175 to 264 Vac rms (247 to 373 Vac peak); the legacy datasheet notes PIMs before revision R and supplies before revision M are limited to 175 to 250 Vac rms |
| Input frequency | 47 to 63 Hz |
| Full rack current draw | 2.3 A rms maximum (175 to 254 Vac input) |
| Replacement fuse | 01720025 (shared with the Low Voltage ac PIM and the legacy High Voltage dc PIM) |
| Partner supply module | 127610-01 ac Power Supply Module |
| Mounting | Half-height module behind the power supply, left side of the rack |
| Supply module operating temperature | -30 to +65 °C (-22 to +150 °F); storage -40 to +85 °C; 95% non-condensing |
| Format | Half-height special module; the supply module and PIM together serve one power supply position |
An over-voltage condition causes the fuse on the PIM to open, which protects the supply. Under-voltage does not harm the supply or the PIM, according to the manufacturer.
Role of the PIM in a redundant power arrangement
A 3500 rack can hold one or two power supplies in the two half-height slots at the left of the rack, and either supply can power a full rack. When two are fitted the lower one is the primary and the upper is the backup. Removing or inserting one module does not disturb the rack as long as the second supply is installed. Each supply has its own PIM, so 125840-01 serves one supply and the rack can be kept running while the PIM or supply on the other feed is serviced.
Compatible and related parts
| Part number | Description | Notes |
|---|---|---|
| 125840-01 | High Voltage ac PIM | This item; 175 to 264 Vac rms |
| 125840-02 | Low Voltage ac PIM | 85 to 132 Vac rms, 110 V nominal |
| 127610-01 | ac Power Supply Module | Legacy supply that these PIMs serve |
| 129478-01 | High Voltage dc PIM | 88 to 140 Vdc |
| 133300-01 | Low Voltage dc PIM | 20 to 30 Vdc |
| 106M1081-01 | Universal AC Power Input Module | Current generation; not interchangeable with 125840-01 |
| 01720025 | Replacement fuse | For ac PIMs and high-voltage dc PIM |
Selection checklist for 125840-01
- Read the part number on the existing PIM: only a High Voltage ac PIM, marked 125840-01, should replace another high-voltage ac unit.
- Confirm the rack really has the legacy supply. If the rack carries a Universal AC supply, ask for 106M1081-01 instead.
- Check the site mains voltage and its tolerance, including worst-case high line, against the 175 to 264 Vac rms rating.
- Note the supply module revision, since early supplies and PIMs have a lower 250 Vac limit.
- Decide whether to also replace the fuse and the supply module as a matched set.
Installation and maintenance
Isolate the incoming mains at the source and verify with a meter before opening any power cover. Rear cover 128085-01 and its screws protect the input connector, so refit them after the work. With a redundant pair, the second supply keeps the rack alive during a PIM change, but plan the work for a quiet time and tell operations, because a mistake on a single-supply rack will drop machinery protection.
After the change, check the power supply OK LED, verify that the rack modules show healthy, and log the fuse type. A blown fuse after energizing usually means over-voltage or a short on the input, and it should be investigated before another fuse is fitted. Include the PIM in your preventive maintenance records with the date and mains voltage measured.
Typical applications in Oman and the GCC
The 3500 racks that still use legacy AC supplies are found on long-running gas turbine generators, compressor trains and steam turbines at oil and gas, power and petrochemical sites in Oman and the GCC. These stations commonly run from 230 V or 240 V mains or UPS output, so the High Voltage ac PIM is the usual type. Because the supply sits inside an air-conditioned control room cabinet, the main risks are old components, voltage disturbances and dust on connectors rather than ambient heat.
Information to send with your RFQ for 125840-01
- Part number 125840-01 and quantity.
- Photo of the PIM label and the supply module label, with revision numbers.
- Site AC voltage and whether the rack has one or two power supplies.
- Delivery country and requested date.
Related Bently Nevada products: Bently Nevada 125680-01 3500/40M Proximitor I/O Module, Bently Nevada 128240-01 3500/42M Prox/Seismic I/O Module, Bently Nevada 3500/50 Tachometer Module, Bently Nevada 149369-01 3500/25 Enhanced Keyphasor Module, Bently Nevada 3500/50M Tachometer Module and Bently Nevada 3500/20 Rack Interface Module.
Documents and quotation
Send the part number 125840-01 and photos of the existing power modules, and we will confirm which documents and test records are available for the unit before the quotation. The manufacturer’s current 3500/15 datasheet describes the family and the generation differences.
Seven Star LLC quotes for Oman and the GCC with stock position, condition and lead time stated clearly.
Datasheets & Documents
- datasheet Bently Nevada 3500/15 AC and DC Power Supply Datasheet Download
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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 is Bently Nevada 125840-01?
It is the High Voltage ac power input module (PIM) for the legacy 3500/15 power supply, rated for 175 to 264 Vac rms at 47 to 63 Hz on 220 V nominal systems.
Is 125840-01 compatible with the Universal AC power supply?
No. The current manufacturer datasheet states that the Universal AC power supply and PIM are not compatible with the legacy AC supplies and the legacy High Voltage and Low Voltage AC PIMs.
What fuse does the 125840-01 use?
The legacy datasheet lists replacement fuse 01720025 for the ac PIMs and the High Voltage dc PIM. An over-voltage event causes this fuse to open, protecting the supply.
What is the difference between 125840-01 and 125840-02?
125840-01 is the High Voltage ac PIM for 220 V nominal systems, while 125840-02 is the Low Voltage ac PIM covering 85 to 132 Vac rms, 110 V nominal.
Can the rack run on one power supply?
Yes. A 3500 rack may have one or two supplies and either supply can power a full rack. With two fitted, the lower supply is primary and the upper supply is backup.
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