Bently Nevada 990 Vibration Transmitter - Datasheet
Description
The 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- 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 occur.1
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.2
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.
Isolation between test equipment and the loop signal, and ensure that the installation maintains machinery protection integrity.
Notes
1 Vibration transmitters have many limitations when compared to a continuous vibration monitoring system. They are a practical solution in some applications for measuring general vibration levels and are a valuable tool for overall vibration trending. However, they provide limited capability for machinery
diagnostics using the vibration signal and do not capture dynamic vibration signals (used for diagnostics) in the event of a vibration alarm. While the transmitter is capable of peak vibration alarming and non-OK checking, the 4-20 mA signal cannot be used to determine the phase of vibration, and monitor functions such as gap alarms, phase alarms, Timed OK channel defeat, Danger Bypass, and Trip Multiply cannot be used. In addition, PLCs attached to the vibration transmitter can only provide peak-to-peak trending data and are not suitable for plant-wide diagnostic systems such as System 1 or Rule Paks.
2 The 990 Vibration Transmitter's PROX OUT coaxial connector provides a non-isolated dynamic transducer signal for machinery diagnostics. You can connect this signal directly to battery-powered or isolated test equipment to diagnose machinery problems. However, since the PROX OUT signal is not isolated from the 4 to 20 mA loop signal, an interface is available (and strongly recommended) for signal isolation. The 990/991 Test Adapter conditions the 990 Transmitter's PROX OUT signal for use with AC-powered test equipment. It also inverts and isolates the 990's transducer signal, making it suitable for equipment such as oscilloscopes and analyzers, and preserving industry-standard conventions for signal polarity. We strongly recommend the use of this test adapter for all applications to maintain.
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.
Accessorie
990/991 Test Adapter. Package includes: 990/991 Test Adapter, 9V battery, Universal AC Adapter, Power Cord (North American), User Guide, and Soft Carrying Case.
The 990/991 Test Adapter inverts and isolates the PROX OUT signal from the 990 Transmitter so that you can connect 990 Transmitters to AC-powered diagnostic equipment. The Adapter modifies the PROX OUT signal so that it matches our standard Proximitor sensor signals by performing these functions:
• Shifts the phase of the PROX OUT signal by 180º by changing the voltage from positive to negative
l Shifts the phase of the PROX OUT signal by 180º by changing the voltage from positive to negative
l Shifts the phase of the PROX OUT signal by 180º by changing the voltage from positive to negative
The 990/991 Test Adapter provides the following benefits:
l Small size and weight for portable operation
l Battery or AC adapter power options
l Automatic shutoff circuit that powers down the unit when the battery is low
l 2 channels, so that you can display an orbit for XY probe configurations.
990/991 Test Adapter Accessories
123266-01 Coaxial Cable Kit. Includes 4 cables with a length of 1.5 meters (5 feet) each
02211505 Single coaxial cable with a length of 1.5 meters (5 feet).
990/991 Test Adapter Spare Parts
01810700 Battery (9-volt alkaline).
02270056 AC adapter. Has a universal AC input to 9 volts DC output. Input is 108 to 132 Vac with 120 Vac nominal, or 207 to 253 Vac with 240 Vac nominal.
02198937 Power cord (for North American AC power outlet).
Probe and Transmitter Accessories
02173006 Bulk cable (specify length in feet). 1.0 mm2 (18 AWG), 2-conductor, twisted, shielded cable used for the 4 to 20 mA loop. Also used for the PROX OUT signal on the 990 Transmitter's terminal strip.
123655 990/991 Transmitter System Installation User Guide
330153-05 Cable Connector Kit. Package includes 1 set of 75 Ω miniature male and female connectors, shrink tubing, and 3300 Isolator Seal for protection of coaxial connectors.
163356 Connector Crimp Tool Kit. Includes one set of 75 Ω ClickLoc inserts and connector installation instructions. Supplied with carrying case.
330951-01 990 Mounting Screws (spares). Contains 4 screws.
284726 DIN rail mounting kit. Installed on the 990 Transmitter to allow mounting on a 35 mm DIN rail.
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130120-0025-01
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130120-0100-01
130120-0250-01
130120-0500-01
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130120-0050-02
130120-0100-02
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