Bently Nevada 2789-120 Extension Cable Product Specification
2789-120 is factory pre-calibrated matched coaxial extension cable for Bently Nevada eddy current proximity transducer system. It bridges the short integral pigtail of proximity probe and corresponding proximitor to form a complete closed measurement circuit in TSI machinery protection systems complying with API 670 standard. Widely used in power, petrochemical and metallurgical industries for steam turbines, turbo-generators, centrifugal compressors and large industrial blowers, it transmits gap-proportional analog voltage signals to proximitors and subsequent 3500 rack monitor modules to implement real-time radial vibration, axial displacement and Keyphasor pulse monitoring plus abnormal alarm and safety shutdown interlock. Each finished cable undergoes continuity inspection, impedance matching calibration, insulation resistance test and high-low temperature cycling aging before shipment to sustain stable signal delivery under harsh environments with high temperature, lubricant oil mist and complicated electromagnetic interference inside bearing housings and control cabinets.
Description
Bently Nevada 2789-120 Extension Cable Product Specification
1. Product Overview
2789-120 is factory pre-calibrated matched coaxial extension cable for Bently Nevada eddy current proximity transducer system. It bridges the short integral pigtail of proximity probe and corresponding proximitor to form a complete closed measurement circuit in TSI machinery protection systems complying with API 670 standard. Widely used in power, petrochemical and metallurgical industries for steam turbines, turbo-generators, centrifugal compressors and large industrial blowers, it transmits gap-proportional analog voltage signals to proximitors and subsequent 3500 rack monitor modules to implement real-time radial vibration, axial displacement and Keyphasor pulse monitoring plus abnormal alarm and safety shutdown interlock. Each finished cable undergoes continuity inspection, impedance matching calibration, insulation resistance test and high-low temperature cycling aging before shipment to sustain stable signal delivery under harsh environments with high temperature, lubricant oil mist and complicated electromagnetic interference inside bearing housings and control cabinets.
2. Part Number Definition
2789 represents the base series of standard calibrated coaxial extension cable for Bently eddy current probe systems; suffix 120 defines fixed factory-calibrated overall cable length, dual-end connector specification, inner coaxial structure and outer sheath material configuration. This model is preset for specific matching probes and proximitors; replacement with unmatched non-original cables will invalidate the whole system’s original factory calibration and result in measurement deviation.
3. Core Functional Features
Constructed with double-layer full shielded coaxial internal structure, the cable effectively suppresses external electromagnetic interference and high-frequency signal attenuation during transmission to secure system linearity. High-temperature and oil-resistant outer sheath safeguards inner insulation and conductors against mechanical abrasion, extrusion and long-term lubricant corrosion. Standard gold-plated coaxial connectors are pre-installed on both terminals for accurate positioning and locked connection with probe tail and proximitor port, reducing intermittent signal faults caused by loose contact. Fixed cable length is precisely calibrated at factory to retain original sensitivity and linear measurement range of matched proximity measuring loop.
4. Electrical Specifications
Compatible with standard Bently proximitor negative DC supply ranging from -17.5VDC to -26VDC. Characteristic impedance and distributed capacitance are strictly factory-calibrated to coordinate with paired proximity probe, minimizing high-frequency signal reflection loss. Premium internal insulating material maintains high insulation resistance to prevent signal drift induced by dampness or oil infiltration into cable core. Only designated original matching probes and proximitors are allowed to assemble with this cable to preserve factory measuring precision.
5. Environmental Working Parameters
Continuous operating temperature of cable body ranges from -40°C up to +177°C, suitable for high-temperature laying near bearing pedestals and regular cabinet wiring. Spare storage temperature is controlled between -55°C and +95°C under non-condensing ambient condition; applicable working relative humidity covers 5%RH~95%RH with surface condensation prohibited. The cable withstands routine industrial vibration of 10Hz~2kHz from running equipment; long-term continuous exposure to strong corrosive gas and persistent hot steam immersion is forbidden to extend service life of inner components. Shorten regular inspection cycle appropriately for installation above 1000 meters altitude.
6. Installation and Routine Maintenance Guidance
During field routing, separate cable path from high-voltage power lines and strong magnetic devices to avoid cross interference and reserve proper cable slack for thermal expansion and equipment vibration instead of overstretching. Align connector positioning notches completely before tightening lock nuts for full engagement. In periodic maintenance, regularly check outer sheath integrity and connector fastening tightness to eliminate hidden signal failure risks. For on-site replacement, only identical part number 2789-120 spare cable can be directly installed. All replacement products complete full factory calibration and aging test prior to delivery to guarantee full interchangeability during unit overhaul.
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