The Bently Nevada 990-04-50-02-05 belongs to the reliable 990 Vibration Transmitter series. This device accepts one non-contacting 3300 NSv Proximity Probe and extension cable. It converts shaft vibration directly into a 4-20 mA industrial signal. Many plants use this transmitter for critical machinery protection.
Input: The 990-04-50-02-05 accepts one 3300 NSv Proximity Probe with extension cable. You must gap the probe between 0.5 and 1.75 mm (20 to 55 mils) from the target. This gap ensures the full-scale range works correctly.
Power Requirements: This transmitter needs a +12 to +35 Vdc input at its terminal. It operates as a 2-wire loop-powered device. The 4 to 20 mA output matches the specified full-scale range.
Full-Scale Option: The unit uses 0-4 mils pp (0-100 μm pp) as its measurement span. This range suits small vibration amplitudes on high-speed rotating machinery.
Output Accuracy: Loop accuracy stays within ±1.5% over the full-scale range. Bently Nevada rates this accuracy from the TEST signal input to a 250 Ω load. Note that this error adds to the Prox Out Incremental Scale Factor.
Frequency Response: The response covers 5 Hz to 6,000 Hz (+0, -3 dB). Therefore, it captures both low-speed and high-speed vibration events.
Maximum Loop Resistance: You can use up to 1,000 Ω including cable at 35 Vdc. For example, a 250 Ω resistor works well with a 24 Vdc supply.
Current Limiting: The typical current limit is 23 mA. This protects the loop during fault conditions.
NOT OK / Signal Defeat: When a NOT OK condition occurs, the output drops below 3.6 mA within 100 µs. After the fault clears, the signal restores within 2-3 seconds.
The 990-04-50-02-05 includes the Agency Approval Option 05. It carries CSA Division 2, ATEX Zone 0, ATEX Zone 2, and ABS maritime approval. This makes it suitable for refineries, offshore platforms, and chemical plants.
Mounting Option: The unit uses 02 Bulkhead screws for secure installation. You can attach it directly to a panel or junction box.
System Length Option: The cable length is 5.0 metres (16.4 feet). This length connects the probe to the transmitter without extra junction boxes.
Transmitter Weight: It weighs only 0.43 kg (0.9 lbm). The shipping gross weight is 0.65 kg including packaging.
Leadwire Length: The maximum distance for the Proximitor Sensor Output (BNC connector) is 3 meters (10 feet). Keep this in mind during system layout.
Minimum Target Size: You need a target at least 9.5 mm (0.375 in) in diameter. Smaller targets reduce measurement linearity.
First, mount the Bently Nevada 990-04-50-02-05 using the bulkhead screws. Ensure the enclosure supports the specified environmental conditions. Next, connect the 3300 NSv Proximity Probe and extension cable to the input.
Then, apply DC power between +12 and +35 Vdc to the transmitter terminals. Use a two-wire shielded cable for the 4-20 mA loop. The maximum loop resistance must not exceed 1,000 Ω at 35 Vdc.
After wiring, gap the probe correctly. The recommended gap range is 0.5 to 1.75 mm (20 to 55 mils). Use the external zero and span adjustments to calibrate the output. These adjustments are non-interacting for easy setup.
Additionally, do not exceed the 3-meter cable limit for the BNC connector output. For hazardous locations, use an approved power supply rated at 28 V.
One Bently Nevada 990-04-50-02-05 990 Vibration Transmitter
Bulkhead mounting screws (02 option)
Factory configuration label
Quick start reference card
1. What probe works with the Bently Nevada 990-04-50-02-05?
This transmitter accepts one 3300 NSv Proximity Probe with its matching extension cable. Do not use other probe models.
2. Can I use this transmitter in a Zone 0 hazardous area?
Yes. The 990-04-50-02-05 includes ATEX Zone 0 approval. It also carries CSA Division 2 and ABS maritime certification.
3. What happens if the probe or cable fails?
The output drops below 3.6 mA within 100 µs. This NOT OK condition alerts your control system immediately.
4. How do I adjust the zero and span on this 990 transmitter?
Use the two external potentiometers on the device. They are non-interacting, so zero adjustment does not affect span.
5. What is the shipping method for this item?
We ship via FedEx, UPS, or DHL. Delivery typically takes 3-7 business days depending on your location.
| Brand Name | Bently Nevada |
| Model No. | 990-04-50-02-05 |
| Product Type | Vibration Transmitter |
| hasMerchantReturnPolicy | Adjust according to reality |
| Shippingdetails | Adjust according to reality |
