Description

The Bently Nevada 990-04-50-01-00 990 Vibration Transmitter is intended primarily for the original equipment manufacturers (OEMs) of centrifugal air compressors or small pumps, motors, or fans who prefer to provide a simple 4 to 20 mA proportional vibration signal as the input to their machinery control system.

The transmitter is a two-wire, loop-powered device that accepts input from our 3300 NSv proximity probe and its matching extension cable (available in 5 m and 7 m system length options). The transmitter conditions the signal into appropriate peak-to-peak vibration amplitude engineering units, and provides this value as a proportional 4 to 20 mA industry-standard signal as the input to the control system where machinery protection alarming and logic occurs.

The 990 transmitter provides the following notable features:

• Integrated Proximitor Sensor requires no external unit.
• Non-isolated "PROX OUT" and "COM" terminals plus a coaxial connector to provide a dynamic vibration and gap voltage signal output for diagnostics.
• Non-interacting zero and span potentiometers under the Transmitter label support loop adjustment.
• Test Input pin for quick verification of loop signal output, using a function generator as the input.
• A Not OK/Signal Defeat circuit prevents high outputs or false alarms due to a faulty proximity probe or loose connection.
• Choice of DIN-rail clips or bulkhead mounting screws as standard options simplifies mounting.
• Potted construction for high humidity (up to 100% condensing) environments.
• Compatibility with 3300 NSv proximity probe allows transducer installation in small areas with minimal clearance, typical of centrifugal air compressors.

Specifications

Unless otherwise noted, the following specifications apply at +22 °C (+72 °F) using a 3300 NSv Probe and Extension Cable, and an AISI 4140 steel target.

Electrical

• Input: Accepts 1 non-contacting 3300 NSv Proximity Probe and extension cable.
• Power: Requires +12 to +35 Vdc input at the transmitter terminal.
• 4 to 20 mA signal output: 4 to 20 mAdc over specified full-scale range in 2-wire configuration.
• 4 to 20 mA loop accuracy: Within ±1.5% over specified full-scale range. Accuracy is rated from the TEST signal input to the voltage measured across a 250 Ω loop resistance.
• Probe gap: Probe must be gapped between 0.5 and 1.75 mm (20 and 55 mils) from target to ensure full-scale range.
• Maximum loop resistance: 1,000 Ω including cable at 35 Vdc.
• Current limiting: 23 mA typical.
• Zero and span: Non-interacting external adjustments.
• NOT OK/signal defeat: Signal output will go to less than 3.6 mA within 100 µs after a Not OK condition occurs. Signal output is restored within 2-3 seconds after the Not OK condition is removed.
• Power-up inhibit: Signal output stays at less than 3.6 mA (NOT O.K.) for 2 to 3 seconds after power is applied. The purpose is to signal that the device is not yet ready. Transients may be observed when the device goes O.K.
• Proximitor sensor output: Compatible with ungrounded, portable test equipment. When using grounded, ac-powered test equipment, use the 122115-01 Test Adapter for signal isolation.
• Output impedance: Prox Out has a 10 kΩ output impedance calibrated for a 10 MΩ load.
• Prox out linear range: 1.4 mm (55 mils). Begins at approximately 0.25 mm (10 mils) from the target surface.
• Prox Out incremental scale factor: 7.87 mV/µm (200 mV/mil) ± 6.5% typical including interchangeability errors when measured in increments of 0.25 mm (10 mils) over the linear range using a flat 30 mm (1.2 inch) target. Worst case 7.87 mV/µm ± 10%.
• Typical Noise Level: 50 mV/pp.
• Temperature stability: Incremental scale factor remains within ±10% of 7.87 mV/µm (200 mV/mil) from 0 °C to +70 °C (+32 °F to +158 °F).
• Frequency response: 5 Hz to 6,000 Hz +0, -3 dB.
• Minimum target size: 9.5 mm (0.375 in) diameter.
• Leadwire length: Maximum for Proximitor Sensor Output (BNC connector), maximum cable distance is 3 metres (10 feet).

Non-Hazardous, Zone 2 or Div 2 Hazardous area locations

• Power Supply: 28V

Intrinsically Safe Hazardous area locations

• Zone 0/1
• Terminal blocks E1-E2 "power supply 4-20 mA"
• Terminal blocks E3-E4 and connector J2 "Proximitor"
• Connector J3 "Probe"
  • Ui [28 V, Uo [28 V, Uo [28 V
  • Ii [120 mA, Io [6 mA, Io [100 mA
  • Pi [0.84 W, Po [0.17 W, Po [0.8 W
  • Ci [20 nF, Co [80 nF, Co [27.3 nF
  • Li [10 μH, Lo [1H, Lo [5.3 mH

Electrical classification

• General Purpose Approval by Canadian Standards Association (CSA/NRTL/C) in North America and by VDE in Europe. 990 has the CE mark for Europe.

Maritime Approvals

• American Bureau of Shipping (ABS) Type Approval
  • Certification Number: 06-HS177078-3-PDA

Environmental Limits

Transmitter Temperature:

• Operating temperature: -35 °C to +85 °C (-31 °F to +185 °F)
• Storage temperature: -51 °C to +100 °C (-60 °F to +212 °F)

Probe Temperature:

• Operating temperature: -35 °C to +177 °C (-31 °F to +350 °F)
• Storage temperature: -51 °C to +177 °C (-60 °F to +350 °F)

Relative humidity: 100% condensing, non-submerged, with protection of coaxial connectors.

Mechanical

• Transducer tip material: Polyphenylene sulfide (PPS).
• Transducer case material: AISI 303 or 304 Stainless Steel (SST).
• Probe Cable: 75Ω coaxial, fluoroethylene propylene (FEP) insulated.
• Cable armor (optional): Flexible AISI 302 SST with optional FEP outer jacket.
• Tensile strength: 222 N (50 lbf) probe case to probe lead, maximum.
• Transmitter weight: 0.43 kg (0.9 lbm).
• Total system weight: 0.82 kg (1.8 lbm) typical.

Ordering Information

990-04-50-01-00

990-AA-BB-CC-DD

A: Full-scale Option

• 0 4: 0-4 mils pp (0-100 μm pp)

B: System Length Option

• 5 0: 5.0 metres (16.4 feet)

C: Mounting Option

• 0 1: 35 mm DIN rail clips

D: Agency Approval Option

• 0 0: Not required