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        991-25-70-01-01

        / 4.9
        1001 reviews ｜ Need a Specific Revision?
        The Bently Nevada 991-25-70-01-01 is a loop-powered 4-20 mA axial position transmitter that directly conditions 3300 NSv eddy current probe inputs into process automation networks.
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        Warranty Policy
        We provide 1 year warranty for all remaining parts.
        The warranty period is one year from the date of shipment, unless otherwise stated in the parts description. We guarantee that the project will not exhibit functional defects that may occur under normal operating conditions during the warranty period.
        Return Notice
        The warranty period is one year from the date of shipment, unless otherwise stated in the parts description. We guarantee that the project will not exhibit functional defects that may occur under normal operating conditions during the warranty period.
        In the event of a defect, we will send new equipment, repair equipment or refund the purchase price based on our availability. You must contact us to obtain a return authorization and return the defective device to us within 14 days of reporting the defect.
        Shipping Mode
        Various transportation options are available in each country. Shipping methods and fees are clearly indicated on all quotations.Various transportation options are available in each country. Shipping methods and fees are clearly indicated on all quotations.
        Parts Availability
        Apter Power offers a wide range of components, products and services related to industrial automation. We also supply new products from a variety of quality manufacturers.
        How to order
        We have been working hard to update our inventory. If we have stock or parts available for new factory purchases, you can contact the order online. If we do not currently have an inventory, the displayed quantity will show "Ask". Please create an online quote or contact us by phone, fax or email to check availability.

        Technical specifications for 991-25-70-01-01

        • Manufacturer:
          Bently Nevada
        • Part Number:
          991-25-70-01-01
        • Product Family:
          991 Thrust Transmitter
        • Product Type:
          Axial position transmitter
        • Stock:
          1
        • Full Scale Range:
          25-0-25 mil (0.6-0-0.6 mm) Axial Displacement
        • System Length:
          7.0 meters (23.0 feet) System Length
        • Mounting Option:
          Panel / Bulkhead Mounting Plate (4-bolt footprint)
        • Agency Approval:
          CSA/NRTL/C Class I Div 2 / Zone 2 Certified
        • Primary Output Signal:
          Proportional 2-Wire 4 to 20 mA DC Current Loop
        • Operating Voltage Range:
          +12 VDC to +30 VDC Loop Powered
        • Maximum Loop Resistance:
          800 Ω @ 30 VDC Supply Voltage
        • Current Output Clamp:
          23 mA Maximum Current Output Under Fault Conditions
        • Buffered Output Impedance:
          50 Ω Nominal BNC Output Impedance
        • Frequency Response:
          0 Hz to 8 Hz (-3 dB Point) Linear Position Tracking
        • Linear Scale Factor:
          0.32 mA/mil (8.0 mA/mm) Proportional DC Output Change
        • Operating Temperature:
          -35°C to +85°C (-31°F to +185°F)
        • Storage Temperature:
          -40°C to +100°C (-40°F to +212°F)
        • Operating Humidity:
          Up to 100% Non-Condensing with Sealed Protective Cover
        • Weight:
          0.43 kg
        • Estimated shipping dimensions:
          81.3 x 86.3 x 61.0 mm
        • Tariff Code:
          8537101190
        • Country of origin:
          USA
        • Place of shipment:
          Xiamen,Fujian,China
        By purchasing this item, you agree to the Terms & Conditions, ApterPower is not an authorized distributor for listed manufacturers or tradenames and therefore the manufacturer's warranty does not apply. All our products come with ApterPower's 1-year warranty.

        More Information

        Overview Manuals Applications Compatibility & Interoperability Configuration Firmware & Updates

        Features:

        • Includes a Not OK/Signal Defeat circuit that drops output current below 3.6 mA within 100 microseconds of probe failure.
        • Employs a Power-up Inhibit circuit to eliminate transient output errors during initial line voltage energization.
        • Features fully potted environmental protection enabling reliable operation in up to 100% condensing humidity conditions.
        Order configuration 991-25-70-01-01 features a 25-0-25 mil measurement scale, a 7.0-meter system electrical length , a flat bulkhead mounting plate chassis, and CSA Class I Division 2 hazardous area approvals.

        Integrated with a dedicated Test Input pin and front panel PROX OUT test terminals, this transmitter allows technicians to rapidly verify loop signal accuracy and monitor raw gap voltages using standard signal generators or diagnostic tools without disconnecting field wiring.

        During system installation, ensure the target material consists of AISI 4140 steel or apply official scale factor correction factors, and verify that the coaxial connector remains clean and isolated from ground loops.

        Availability: Standard Dispatch - Verified In Stock
        Bently Nevada 991-25-70-01-01 Thrust Transmitter Manuals,Datasheets,Link Important Notice: Other accessories, manuals, cables, calibration data, software, etc. are not included with this equipment unless listed in the above stock item description. All prices are shown in USD.
        • Detects differential expansion and rotor displacement on large industrial electric motor thrust bearings.
        • Monitors axial position variations in high-pressure fluid power pumps and hydraulic drive units.
        • Tracks rotor shaft float during thermal startup sequences on industrial gas turbine generator sets.
        • Requires 3300 NSv eddy current proximity sensors with a 50 mil nominal linear range for valid signal output.
        • Matches 7.0-meter extension cable capacitance parameters to prevent non-linear voltage-to-current scale distortion.
        • Requires a minimum loop supply voltage of +12 VDC measured directly across terminals at 20 mA full scale.
        • Factory-trimmed hardware circuits lock the output scale factor to 0.32 mA/mil without digital parameters.
        • Requires precise mechanical sensor target gapping before setting loop zero reference via front potentiometers.
        • Includes high-frequency noise filtering circuits that smooth loop signal outputs against machine electrical noise.
        • Utilizes a pure analog hardware conditioning architecture without digital microprocessors or embedded firmware requirements.
        • Eliminates the need for software flashing, firmware updates, or digital security patch management over its operational life.
        • Maintains permanent hardwired transfer function characteristics that cannot be corrupted or reset by software errors.
        Description
        The Bently Nevada 991-25-70-01-01 is a 2-wire loop-powered 4-20 mA thrust position transmitter engineered for integration into industrial plant monitoring networks. Specified with a 25-0-25 mil full-scale measuring span, a 7.0-meter system electrical setup, a flat bulkhead mounting plate, and CSA Division 2 non-incendive approvals, this solid-state transducer eliminates the necessity for dedicated monitor racks inside instrumentation cabinets.

        Functionally, the Bently Nevada 991-25-70-01-01 conditions dynamic gap voltages from 3300 NSv eddy current proximity sensors into a linear DC current loop proportional to axial shaft movement. It features non-interacting zero and span potentiometers for rapid calibration, alongside a front-accessible BNC jack that provides a 50-ohm buffered raw proximity signal output for temporary connection to handheld spectrum analyzers without interrupting the primary 4-20 mA control loop.

        This transmitter is primarily deployed across critical rotating equipment—including multi-stage boiler feed water pumps, high-pressure centrifugal compressors, industrial steam turbines, and heavy-duty gearboxes—where continuous axial displacement tracking is required. Operating directly on target shafts or thrust collars, the Bently Nevada 991-25-70-01-01 provides early warning of excessive rotor float to protect thrust bearings against mechanical contact and catastrophic failure.
        Alternative Names
        991-25-70-01-01 991 25 70 01 01 99125700101 991257001 Bently Nevada 991-25-70-01-01 991-25-70-01-01 Transmitter 991 Axial Displacement Transmitter 25-70-01-01 Bently Nevada 991 Panel Mount Thrust Monitor
        Technical notes
        When wiring the 4-20 mA current loop on the Bently Nevada 991-25-70-01-01, ensure the total loop resistance including cable run and DCS input impedance does not exceed the maximum load curve threshold for your supply voltage.
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        FAQS

        The following is a list of questions commonly asked by our customers. Please contact us if you have a question about our process that is not answered below.
        VIEW ALL FAQS
        What is the primary purpose of the front-panel BNC port on the Bently Nevada 991-25-70-01-01?
        The BNC connector on the Bently Nevada 991-25-70-01-01 provides an isolated, buffered raw proximity signal output for temporary connection to portable vibration and spectrum analyzer tools without disturbing the primary 4-20 mA loop.
        How does the panel mounting base (-01 option) differ from DIN rail models of the Bently Nevada 991-25-70-01-01?
        Option -01 equips the Bently Nevada 991-25-70-01-01 with a flat baseplate containing four corner screw mounting holes, allowing direct bolt-down attachment onto cabinet backplanes or metal plates.
        What extension cable and sensor system length is mandated for the Bently Nevada 991-25-70-01-01?
        The Bently Nevada 991-25-70-01-01 (-70 option) requires a matched 7.0-meter total system length composed of a 3300 NSv proximity probe and appropriate extension cable to maintain calibrated current output accuracy.
        Is special software or digital programming required to set up the Bently Nevada 991-25-70-01-01?
        No, the Bently Nevada 991-25-70-01-01 is an analog conditioning unit that requires no digital programming; zero and span settings are calibrated manually via non-interacting potentiometers on the front panel.
        Is the Bently Nevada 991-25-70-01-01 compatible with standard 3300 XL 8mm proximity probes?
        No, the Bently Nevada 991-25-70-01-01 is engineered exclusively to operate with Bently Nevada 3300 NSv proximity sensors and matching 3300 NSv extension cables due to its specific internal impedance matching circuitry.
        What replacement verification steps are recommended when ordering the Bently Nevada 991-25-70-01-01 for an existing machine retrofit?
        When ordering a replacement unit, emailing a photo of your existing transmitter's nameplate to Apter Power is recommended to verify that option -25 (range) and option -01 (mounting) match your field setup.

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