991-06-50-01-05 Probe Vibration Transmitter by Bently Nevada

Bently Nevada 991-06-50-01-05 Thrust Transmitter for Axial Monitoring

Product Introduction

The Bently Nevada 991-06-50-01-05 belongs to the 991 series of thrust transmitters. This device converts proximity probe signals into a standard 4-20 mA industrial current loop. Therefore, it works perfectly for axial position measurement in rotating machinery.

Manufactured in the U.S.A., this transmitter accepts a non-contacting 3300 NSv proximity probe and extension cable. Additionally, it requires a DC power supply of +12 to +35 Vdc at the transmitter terminal. The output signal is a 2-wire, 4-20 mA loop that reflects the shaft’s axial displacement.

For installation, the 991-06-50-01-05 includes 35 mm DIN-rail clips. Its system length is 5.0 meters (16.4 feet). The full-scale option is set to 0.6-0-0.6 mm, which matches the linear range from 0.25 mm to 1.65 mm. Consequently, this configuration is suitable for thrust position monitoring in turbines and compressors.

Technical Specifications

Input and Power Requirements

• Accepts one 3300 NSv proximity probe with extension cable.

• Power input: +12 to +35 Vdc at the transmitter terminals.

• Maximum loop resistance: 1,000 Ω (including cable) at 35 Vdc.

• Current limiting occurs at 23 mA typically.

Output Signal and Accuracy

• Output: 4-20 mAdc over the specified full-scale range.

• Loop accuracy is within ±1.5% of full scale (typical).

• Accuracy is rated from the TEST signal input to the voltage measured across a 250 Ω loop resistor.

• Zero and span adjustments are non-interacting and external.

Not OK / Signal Defeat Feature

• Signal output drops below 3.6 mA within 100 µs after a Not OK condition.

• Output restores within 0.1 seconds after the Not OK condition clears.

Environmental Limits and Mechanical Data

Transmitter Temperature Ranges

• Operating temperature: -35°C to +85°C (-31°F to +185°F).

• Storage temperature: -51°C to +100°C (-60°F to +212°F).

Mounting and Weight

• Mounting type: DIN rail with 35 mm clips (mounting option 01).

• Weight: 0.43 kg (0.9 lb).

Agency Approvals

The Bently Nevada 991-06-50-01-05 includes agency approval option 05. These approvals cover:

• CSA Division 2

• ATEX Zone 0

• ATEX Zone 2

• ABS maritime approval

Therefore, this transmitter suits hazardous industrial environments and marine applications.

Installation Guidelines

Follow these steps for a successful installation.

Mounting the Transmitter
First, attach the 35 mm DIN-rail clips to the transmitter body. Next, clip the unit firmly onto a standard DIN rail inside your control cabinet. Ensure adequate airflow around the transmitter.

Connecting the Probe and Power
Then, connect your 3300 NSv proximity probe and extension cable to the input terminals. After that, supply +12 to +35 Vdc to the power terminals. Use shielded cables for best noise immunity.

Adjusting Zero and Span
Finally, apply a known target position. Use the external zero and span adjustments to calibrate the 4-20 mA output. These adjustments are non-interacting, so you can tune each independently.

Packaging List

• 1 x Bently Nevada 991-06-50-01-05 Thrust Transmitter

• 1 x Set of 35 mm DIN-rail clips (pre-installed)

• 1 x Quick start guide (printed)

Note: The probe and extension cable are sold separately.

Shipping Information

All orders are shipped via FedEx, UPS, or DHL. Delivery times depend on your location.

Frequently Asked Questions (FAQ)

1. What probe works with the Bently Nevada 991-06-50-01-05?
This transmitter accepts one 3300 NSv non-contacting proximity probe plus an extension cable. The probe is not included in the package.

2. Can I use this transmitter for radial vibration monitoring?
No. The 991-06-50-01-05 is specifically designed for axial thrust measurement. For radial vibration, please use other Bently Nevada models.

3. What happens if the probe fails or disconnects?
The output signal drops below 3.6 mA within 100 µs. This fast Not OK indication alerts your control system immediately.

4. What is the maximum cable length from transmitter to the loop?
The maximum loop resistance is 1,000 Ω at 35 Vdc. For a 250 Ω loop resistor, you can use long cables. However, always calculate total resistance before installation.

5. Is this transmitter approved for use on ships?
Yes. Agency approval option 05 includes ABS maritime approval. Therefore, it is suitable for marine applications.