Bently Nevada 21747-040-00 Extension Cable Product Specification
21747-040-00 is factory pre-calibrated matched extension cable dedicated to Bently Nevada 7200 and 3300XL standard 8 mm eddy current proximity transducer systems. It serves as the intermediate signal transmission link between field-installed 22810-series proximity probes and cabinet-mounted proximitor preamplifiers, transmitting clearance-proportional analog voltage signals to 3300, 7200 or 3500 rack monitor modules for continuous radial vibration and axial displacement measurement of rotating shafts. Widely applied on steam turbines, gas turbines, centrifugal compressors and large turbo-generators in power generation, petrochemical and metallurgical industries, this calibrated cable preserves the whole sensor loop’s original factory calibration to ensure reliable machinery protection against abnormal over-vibration. Every finished cable undergoes strict impedance consistency inspection, paired full-loop calibration and insulation withstand testing before factory delivery to maintain stable signal transmission under severe industrial conditions with high-temperature bearing compartments, lubricant oil mist and complex electromagnetic interference from variable frequency drives and high-power feed cables.
Description
Bently Nevada 21747-040-00 Extension Cable Product Specification
1. Product Overview
21747-040-00 is factory pre-calibrated matched extension cable dedicated to Bently Nevada 7200 and 3300XL standard 8 mm eddy current proximity transducer systems. It serves as the intermediate signal transmission link between field-installed 22810-series proximity probes and cabinet-mounted proximitor preamplifiers, transmitting clearance-proportional analog voltage signals to 3300, 7200 or 3500 rack monitor modules for continuous radial vibration and axial displacement measurement of rotating shafts. Widely applied on steam turbines, gas turbines, centrifugal compressors and large turbo-generators in power generation, petrochemical and metallurgical industries, this calibrated cable preserves the whole sensor loop’s original factory calibration to ensure reliable machinery protection against abnormal over-vibration. Every finished cable undergoes strict impedance consistency inspection, paired full-loop calibration and insulation withstand testing before factory delivery to maintain stable signal transmission under severe industrial conditions with high-temperature bearing compartments, lubricant oil mist and complex electromagnetic interference from variable frequency drives and high-power feed cables.
2. Part Number Definition Breakdown
Each segmented code of 21747-040-00 follows Bently’s standard extension cable coding specification. Base code 21747 stands for dedicated cable series designed for 8 mm proximity sensors compatible with both 7200 and 3300XL platforms; middle segment 040 defines fixed finished cable length of 4.0 meters; trailing segment 00 indicates standard non-armored construction, PVC outer jacket and factory pre-molded dual 10-pin mini DIN connectors at both ends. Cables with different length codes or suffix configurations carry distinct calibrated electrical parameters and cannot be directly replaced on-site. Improper substitution changes total calibrated loop length, invalidates factory preset calibration and causes measuring deviation or unexpected protection tripping of the monitoring channel.
3. Core Functional Characteristics
The cable features precision 75-ohm controlled-impedance coaxial inner structure to achieve perfect electrical matching with 8 mm 3300XL proximity probes and corresponding proximitor preamplifiers. High-density tinned copper braided shielding with over 95% coverage effectively suppresses power frequency noise and high-frequency crosstalk interference during long-distance routing alongside high-current power cables in cable trenches. Both terminals are permanently factory molded with integrated 10-pin mini DIN connectors; field cutting, splicing or connector modification is strictly prohibited, as any physical alteration permanently voids original factory calibration of the complete transducer system. Standard PVC outer jacket protects inner core from industrial dust, occasional light oil splashing and routine mechanical abrasion during long-term equipment operation. Each cable is calibrated together with matched probe and proximitor at factory to retain consistent linear output characteristics of the entire measurement circuit.
4. Electrical and Construction Specifications
Uniform 75-ohm characteristic impedance is maintained across the full 4.0-meter cable length in compliance with Bently 3300XL system design standards to secure complete signal integrity from probe tip to proximitor input port. Two terminals adopt original factory 10-pin mini DIN molded connectors for probe side and proximitor side connection respectively. This fixed 4.0-meter length is accumulated with the integral built-in cable of paired 22810-series probes to calculate total calibrated loop length required for corresponding proximitor configuration. Low-loss and low-capacitance inner insulating material restrains signal attenuation within full working frequency band ranging from DC up to 10 kHz. All finished cables complete pairing calibration with designated transducer groups before shipment; random cross matching with extension cables of different lengths is forbidden during field maintenance.
5. Environmental Working Parameters
Continuous permissible operating ambient temperature ranges from -40°C to +85°C for regular installation near bearing housings and control cabinets. Spare storage temperature is controlled between -55°C and +90°C under dry non-condensing storage environment; applicable working relative humidity covers 5%RH to 95%RH without dew condensation accumulating on cable outer surface. The cable can withstand routine mechanical vibration of 10 Hz to 2 kHz generated by adjacent running rotating equipment. Long-term continuous immersion in corrosive liquid, acid mist and persistent high-temperature steam is prohibited to prevent outer jacket cracking and inner insulation aging. For installation locations above 1000 meters altitude, shorten periodic inspection cycle appropriately.
6. Installation and Routine Maintenance Guidance
Separate transducer signal cable routing away from high-current AC power cables and inverter output wiring during field cabling construction to minimize cross electromagnetic coupling interference. Avoid sharp small-radius bending, excessive stretching and heavy mechanical extrusion on cable body to prevent internal conductor damage and unexpected impedance variation. Within regular maintenance cycles, periodically inspect PVC jacket surface for oil corrosion, abrasion and cracking, and check locking condition of dual-end connectors to eliminate intermittent signal fluctuation caused by loose contact. When cable failure requires on-site replacement, only spare part with identical full part number 21747-040-00 is permitted for direct swap. All replacement cables complete impedance inspection and calibration matching test before factory outbound delivery to guarantee full interchangeability inside original vibration monitoring loops.
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