Bently Nevada 991-06-50-02-05 Probe Vibration Transmitter
Product Introduction
The Bently Nevada 991-06-50-02-05 belongs to the trusted 991 Series of thrust transmitters. This device measures axial displacement in rotating machinery. It works with a non-contacting 3300 NSv proximity probe. Additionally, it converts the probe signal into a standard 4-20 mA industrial current loop. Many plants use this model for compressor and turbine thrust monitoring.
For instance, the full-scale range is set to 0.6-0-0.6 mm. This makes it ideal for precise axial position measurement. The system length option -50 means a 5.0 meter (16.4 feet) cable. Furthermore, the mounting option 02 includes bulkhead screws for secure installation.
Technical Specifications
Input and Power Requirements
The Bently Nevada 991 accepts one 3300 NSv proximity probe and extension cable. Power requirements include +12 to +35 Vdc at the transmitter terminal. Therefore, it works with most standard 24 Vdc power supplies.
Output Signal and Accuracy
This transmitter provides a 4-20 mA output in a 2-wire configuration. The current loop linear range matches 0.6-0-0.6 mm or 25-0-25 mils. Typical loop accuracy is within ±1.5% of the full-scale range. Additionally, the maximum loop resistance reaches 1,000 Ω at 35 Vdc. Current limiting occurs at 23 mA typically.
Linear Range and Not OK Function
The linear range for proximity output is 0.25 to 1.65 mm. Zero and span adjustments are non-interacting and external. Meanwhile, the Not OK/Signal Defeat feature forces output below 3.6 mA within 100 µs. The output restores within 0.1 seconds after the Not OK condition clears.
Mechanical and Environmental Limits
Temperature Ratings
The transmitter operates from -35°C to +85°C (-31°F to +185°F). Storage temperature ranges from -51°C to +100°C (-60°F to +212°F). Consequently, this device suits harsh industrial environments.
Weight and Mounting
Weight is only 0.43 kg (0.9 lbm). Mounting is via DIN rail, which simplifies installation in control cabinets. The bulkhead screw option adds extra mechanical security.
Agency Approvals
This model carries approval option 05. Approvals include CSA Division 2, ATEX Zone 0, ATEX Zone 2, and ABS maritime approval. Therefore, you can use it in hazardous areas and marine applications.
Installation Guidelines
First, mount the Bently Nevada 991 securely on a standard DIN rail inside an enclosure. Next, connect the 3300 NSv proximity probe and extension cable to the input terminals. Then, wire the 4-20 mA loop to a power supply between +12 and +35 Vdc.
For instance, use a 250 Ω resistor to measure voltage across the loop for testing. The TEST signal input allows verification of zero and span adjustments. Ensure the total loop resistance does not exceed 1,000 Ω. Finally, adjust the non-interacting zero and span pots to match the 0.6-0-0.6 mm range.
Packaging List
Bently Nevada 991-06-50-02-05 Probe Vibration Transmitter – 1 unit
Bulkhead screws (mounting option 02) – included
5.0 meter system length cable – pre-attached
Product manual – 1 copy
Note: No certificates or warranty documents are included in the package.
Shipping
All orders ship via FedEx, UPS, or DHL. Tracking numbers are provided after dispatch.
Frequently Asked Questions (FAQ)
Q1: What type of probe works with the Bently Nevada 991-06-50-02-05?
A1: It accepts one 3300 NSv non-contacting proximity probe and extension cable.
Q2: Can I use this transmitter in a Zone 0 hazardous area?
A2: Yes. It has ATEX Zone 0, Zone 2, and CSA Division 2 approvals.
Q3: What happens during a Not OK condition?
A3: The output drops below 3.6 mA within 100 µs and restores quickly after the fault clears.
Q4: What is the maximum loop resistance allowed?
A4: The maximum is 1,000 Ω including cable resistance at 35 Vdc input.
Q5: How do I adjust the zero and span settings?
A5: Use the two external, non-interacting potentiometers on the transmitter body.
