Where is the electrical midpoint of 991-25-70-01-01?

The 25-0-25 mil axial range places the zero-position reference at midspan. Verify both movement directions and the configured control-system indication when calibrating the loop.

Does 991-25-70-01-01 report radial vibration amplitude on its main loop?

No. Its 4-20 mA signal represents axial shaft position. Dynamic probe information is available separately at the non-isolated PROX OUT connection.

Which total transducer length is required by 991-25-70-01-01?

The selected electrical system length is 7.0 m. Combine the compatible 3300 NSv probe and extension cable to that total; the external loop wiring is a separate circuit.

Can 991-25-70-01-01 share a grounded oscilloscope connection without isolation?

PROX OUT and COM are non-isolated. Use the specified test adapter when connecting grounded AC-powered equipment so that the diagnostic instrument does not disturb the measurement circuit.

How does 991-25-70-01-01 behave immediately after loop power is applied?

During the approximately 2-3 second power-up inhibit, the signal remains below 3.6 mA. The control system must distinguish this initial Not OK condition from valid axial-position data.

What test stimulus is appropriate for the TEST input of 991-25-70-01-01?

Use a variable DC voltage source under the transmitter test procedure. This exercises the axial-position loop; an AC vibration generator is the corresponding test method for a 990 vibration transmitter.

Why does a loose probe connection affect 991-25-70-01-01 differently from real thrust movement?

The Not OK/Signal Defeat circuit drives the loop below 3.6 mA rather than allowing a failed transducer path to appear as a valid high thrust signal.

Which mounting and area selections belong to 991-25-70-01-01?

The 01 mounting selection uses 35 mm DIN-rail clips, and the final 01 selects CSA Division 2. Match the supplied markings and installation conditions before using that area classification.

991-25-70-01-01

Name: 991-25-70-01-01
Brand: Bently Nevada
SKU: 991-25-70-01-01

Thrust Transmitter

Product image is representative; revision or series may vary. Contact us to request a specific version.

Product Describe：

Bently Nevada 991-25-70-01-01 is a two-wire axial-position transmitter with a 25-0-25 mils span and a 7.0 m 3300 NSv transducer system.

Manufacturer part number
991-25-70-01-01
Shipping
Swift global dispatch
Condition
New, original product
Shipping size (est.)
10cm x 7.4cm x 6cm
Country of Origin
USA

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What happens after you enquire

0

Review your reference

Send the complete Bently Nevada 991-25-70-01-01 reference, label photographs and required quantity. Include the 25-0-25 mils scale and 7.0 m transducer chain.
1

Confirm the offer

Review the offered revision, condition, included items and documents against the confirmed installation.
2

Arrange dispatch

Confirm quantity, dispatch date, lead-time start and delivery details in the quotation.

Match the complete marking

Include the complete Bently Nevada 991-25-70-01-01 marking and any hardware revision on the item. Include the 25-0-25 mils scale and 7.0 m transducer chain.
Check the offered item before ordering

Request available label and connector photos. Have your maintenance team compare the offered 991-25-70-01-01 with the installed equipment and applicable Bently Nevada documentation.

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

Manufacturer:

Bently Nevada
Product Category:

Machinery Monitoring Systems
Spare Part Number:

991-25-70-01-01
Weight:

0.5 kg
Tariff Code:

8537101190
Measurement:

Axial position
Full-scale span:

25-0-25 mils
Electrical system length:

7.0 m
Signal output:

4-20 mA; two-wire
Terminal supply:

+12 to +35 VDC
Maximum loop resistance:

1000 ohms at 35 VDC; includes cable
Current limit:

23 mA typical
Mounting:

35 mm DIN-rail clips
Transmitter temperature:

-35 to +85 degrees C
Fault current:

Below 3.6 mA

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Information

Overview Downloads Applications / Compatibility Product Precautions

Bently Nevada 991-25-70-01-01 brings shaft thrust position into the machinery controller through a powered current loop, while retaining a separate diagnostic connection for the probe signal.

Measurement span: 25-0-25 mils
Transducer system: 7.0 m, compatible 3300 NSv probe and cable
Mounting: 35 mm DIN-rail clips

The selected configuration combines a 25-0-25 mils measurement span, a 7.0 m transducer system and 35 mm din-rail clips. The integrated proximity conditioner accepts one compatible 3300 NSv probe with its matched extension cable; the probe lead and extension together establish the calibrated length.

The two-wire loop supplies power and transmits axial shaft position as 4-20 mA. The receiving control system supplies the alarm and protection logic. Non-interacting zero and span adjustments support loop calibration, while the TEST input accepts a variable DC voltage source for controlled output checks.

The separate PROX OUT/COM and coaxial connection provide the dynamic and gap signal for diagnosis. This output is non-isolated and must be used with the specified test arrangement. Not OK/Signal Defeat drives the loop below 3.6 mA on a faulty transducer connection; power-up and fault recovery require approximately 2-3 seconds.

Controller platform reference: 3300 NSv transmitter system. Retain the calibrated chain and receiver scale.

The original technical excerpt for Bently Nevada 991-25-70-01-01 covers transmitter operation, electrical limits and diagnostic connections. The separate installation guide covers measurement scaling, loop burden, cable matching and controlled loop tests.

Original manufacturer pages retain their technical context. Use the Apter Power guide with the applicable manufacturer instructions and approved installation design.

System and supply context: 991-25-70-01-01 connects a matched NSv probe and extension to a powered current-loop receiver. Probe, cable, test adapter and receiving control equipment are separate unless included in the quotation.

Application scope: Use the 25-0-25 mils scale for axial-position supervision of the assigned machine point. Protective alarm logic remains in the receiving system.

Machine-point signal conditioning
Convert one axial position measurement into a 4-20 mA input for the controller.
Calibrated loop renewal
Retain the 25-0-25 mils receiver range and 7.0 m electrical chain when replacing the transmitter.
Probe-signal diagnosis
Observe the dynamic and gap signal with the specified diagnostic connection and instrument isolation.
Protection-loop verification
Use the TEST input with a variable DC voltage source to compare signal output and receiving indication.

Prepare Bently Nevada 991-25-70-01-01 for its configured installation using these checks.

Retain the measurement scale

Keep 25-0-25 mils and its units in the receiver configuration.

Match the calibrated chain

The probe and extension together must equal 7.0 m.

Check loop burden

Provide the required terminal voltage after wiring and receiver losses.

Keep test grounding controlled

The diagnostic connection is non-isolated.

Recognize Not OK

Distinguish below-3.6 mA fault and startup states from valid measurements.

Restore protection deliberately

Remove test inputs and verify stable measurement before clearing the approved bypass.

Alternative Names

991 25 70 01 01 Bently Nevada 991-25-70-01-01

Technical notes

Receiver configuration: Set the receiver for a bipolar axial-position span. A zero-position reference belongs at midspan, so both thrust directions need to be included in the loop test.

Test isolation: Use the specified isolated test arrangement when attaching grounded instruments to the non-isolated diagnostic connection.

FAQ View All FAQ

Where is the electrical midpoint of 991-25-70-01-01?

The 25-0-25 mil axial range places the zero-position reference at midspan. Verify both movement directions and the configured control-system indication when calibrating the loop.
Does 991-25-70-01-01 report radial vibration amplitude on its main loop?

No. Its 4-20 mA signal represents axial shaft position. Dynamic probe information is available separately at the non-isolated PROX OUT connection.
Which total transducer length is required by 991-25-70-01-01?

The selected electrical system length is 7.0 m. Combine the compatible 3300 NSv probe and extension cable to that total; the external loop wiring is a separate circuit.
Can 991-25-70-01-01 share a grounded oscilloscope connection without isolation?

PROX OUT and COM are non-isolated. Use the specified test adapter when connecting grounded AC-powered equipment so that the diagnostic instrument does not disturb the measurement circuit.

How does 991-25-70-01-01 behave immediately after loop power is applied?

During the approximately 2-3 second power-up inhibit, the signal remains below 3.6 mA. The control system must distinguish this initial Not OK condition from valid axial-position data.
What test stimulus is appropriate for the TEST input of 991-25-70-01-01?

Use a variable DC voltage source under the transmitter test procedure. This exercises the axial-position loop; an AC vibration generator is the corresponding test method for a 990 vibration transmitter.
Why does a loose probe connection affect 991-25-70-01-01 differently from real thrust movement?

The Not OK/Signal Defeat circuit drives the loop below 3.6 mA rather than allowing a failed transducer path to appear as a valid high thrust signal.
Which mounting and area selections belong to 991-25-70-01-01?

The 01 mounting selection uses 35 mm DIN-rail clips, and the final 01 selects CSA Division 2. Match the supplied markings and installation conditions before using that area classification.

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