Description

The Bently Nevada 3300/20-12-01-02-00-00 serves as the primary 3300/20 Dual Thrust Position Monitor utilized to execute continuous axial shaft movement tracking across Bently Nevada 3300 System platforms. The dual-channel instrument processes continuous voltage signals delivered by proximity transducer links to track shaft movement relative to internal thrust bearing clearances. It quantifies localized millimeter or mil shifts, flags abnormal rotor displacement, and trips connected interlock relays to prevent catastrophic axial rotor-to-stator friction. The module provides real-time electrical conversion of rotor movement inside a single dedicated instrumentation rack slot.

Suffix Breakdown & Model Matrix

• 3300/20: Base Series Identifier for the Dual Thrust Position Monitor.
• -12: Full-scale Range Option specifying 25-0-25 mils.
• -01: Agency Approval Option confirming CSA/NRTL/C Class I, Division 2 certifications.
• -02: Intrinsic Safety Inserts Option establishing internal zener barriers for direct hazardous-area field wiring.
• -00: Output Option provisioning standard 4-20 mA proportional analog DC outputs per channel.
• -00: Special Modifications Option designating a standard factory hardware and firmware configuration.

Hardware Specifications

Eddy-Current Scaling and TSI Performance

The diagnostic processing pathways rely on consistent eddy-current probe scaling configurations, calibrated for a standard 200 mV/mil linear scale factor using 3300 XL 8 mm proximity transducers. Field engineers execute gap voltage validation via front-panel buffered outputs to ensure the static probe tip registers within the center of the calibration arc, targeting a baseline offset of -10 VDC. This precise configuration tracks high-speed axial shifts and rotor dynamics under varying thermal thrust conditions. Advanced internal filters suppress signal cross-talk when dual probes mount adjacently on the same shaft counterbore face, maintaining high-fidelity transient position tracing without electronic channel interference.

Frequently Asked Questions

Q: Does this specific thrust monitor support an AND voting configuration logic loop for trip mitigation?

A: Yes. The 3300/20 card features selectable internal circuit jumpers that allow field technicians to configure channel 1 and channel 2 in an AND voting logic layout. This prevents a single transducer failure from initiating a false machinery emergency shutdown sequence.

Q: Can the 4-20 mA current outputs drive external plant DCS recording loops without secondary isolators?

A: Yes. The proportional 4-20 mA current loops are fully isolated, allowing direct integration into external plant distributed control systems or programmable logic controllers without generating ground loop errors.

Field Installation Guidelines

• Verify that the rack bypass plug or the safety interlock loop is properly engaged prior to inserting the monitor module to avoid sending an accidental trip command during seating.
• Secure the card faceplate screws tightly into the frame to ground the aluminum chassis plate and optimize radio frequency interference immunity.
• Terminate the shield wires of the field extension coax lines at the backplane block only, completely separating the floating shield layer from structural machine ground grids.
• Mount the two axial probes exactly 180 degrees apart when targeting the same thrust collar surface to ensure accurate complementary mechanical validation across the primary axis.