Bently Nevada 2789-144 Extension Cable Product Specification
2789-144 is factory pre-calibrated matched coaxial extension cable used for Bently Nevada eddy current proximity transducer measurement system. It connects the short integral lead of proximity probe and corresponding proximitor to form a complete closed signal loop, complying with API 670 turbomachinery protection standards. Widely applied in power plant, petrochemical and metallurgical industries for steam turbine, turbo-generator, centrifugal compressor and large blower TSI monitoring system, it transfers gap-variation analog signals from probe to proximitor and then to 3500 rack monitor modules to realize real-time measurement of radial vibration, axial thrust displacement and Keyphasor rotational pulse, as well as equipment abnormal alarm and safety interlock protection. Every finished cable passes continuity test, impedance matching calibration, insulation test and high-low temperature cycling aging test before delivery to ensure stable signal transmission under harsh conditions of high temperature, oil mist and complex electromagnetic interference inside bearing housings and control rooms.
Description
Bently Nevada 2789-144 Extension Cable Product Specification
1. Product Overview
2789-144 is factory pre-calibrated matched coaxial extension cable used for Bently Nevada eddy current proximity transducer measurement system. It connects the short integral lead of proximity probe and corresponding proximitor to form a complete closed signal loop, complying with API 670 turbomachinery protection standards. Widely applied in power plant, petrochemical and metallurgical industries for steam turbine, turbo-generator, centrifugal compressor and large blower TSI monitoring system, it transfers gap-variation analog signals from probe to proximitor and then to 3500 rack monitor modules to realize real-time measurement of radial vibration, axial thrust displacement and Keyphasor rotational pulse, as well as equipment abnormal alarm and safety interlock protection. Every finished cable passes continuity test, impedance matching calibration, insulation test and high-low temperature cycling aging test before delivery to ensure stable signal transmission under harsh conditions of high temperature, oil mist and complex electromagnetic interference inside bearing housings and control rooms.
2. Part Number Definition
2789 stands for standard series of calibrated extension coaxial cable for Bently eddy current probe system; suffix 144 defines fixed calibrated total length, double-end connector specification, inner coaxial structure and outer sheath configuration. This model is preset for designated matching probes and proximitors at factory; using non-matching alternative cables will destroy the whole system’s original calibration parameters and cause measuring error.
3. Core Functional Features
Double-layer full shielded coaxial inner structure effectively restrains external electromagnetic interference and high-frequency signal attenuation during transmission, keeping linearity of the whole transducer system. High temperature and oil resistant outer sheath protects inner insulation and conductor from mechanical scratch, extrusion damage and lubricant corrosion during long-term running. Standard gold-plated coaxial connectors are pre-installed on both cable ends for precise positioning and tight locking connection with probe tail and proximitor port, avoiding intermittent signal fault from poor contact. The fixed cable length is strictly calibrated in production to retain original sensitivity and linear measuring range of matched proximity sensor set.
4. Electrical Specifications
Compatible with standard proximitor negative DC power of -17.5VDC ~ -26VDC. Characteristic impedance and distributed capacitance are precisely calibrated to match paired proximity probe, minimizing high-frequency signal reflection loss. Superior inner insulating material maintains high insulation resistance to prevent signal drift caused by moisture or oil permeation into cable core. Only original matched probe and designated proximitor can be matched with this cable to keep factory calibrated measuring accuracy unchanged.
5. Environmental Working Parameters
Continuous operating temperature of cable body ranges from -40°C to +177°C, suitable for high-temperature routing near bearing seats and indoor cabinet wiring. Spare storage temperature is -55°C ~ +95°C under non-condensing condition; applicable relative humidity covers 5%RH~95%RH with no dew condensation allowed on cable surface. The cable can withstand regular industrial vibration of 10Hz~2kHz from running rotating equipment. Long-term continuous soaking in corrosive liquid or persistent hot steam environment is forbidden to protect inner conductor and insulation layer. For installation above 1000 meters altitude, shorten regular inspection cycle properly.
6. Installation and Routine Maintenance Guidance
During field wiring, separate cable path from high-voltage cables and strong magnetic equipment to avoid cross interference, leave appropriate cable slack for thermal expansion and unit vibration instead of over tension. Align connector locating notch fully before tightening lock nut to ensure full insertion and reliable connection. In periodic maintenance, regularly check cable sheath integrity, connector fastening tightness and aging damage. If replacement is needed on site, only spare part with identical part number 2789-144 can be directly swapped. All replacement cables complete full factory calibration and aging test before delivery to guarantee interchangeability during equipment overhaul.
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