Bently Nevada 21747-080-00 Extension Cable

Product Introduction

The Bently Nevada 21747-080-00 is an extension cable for 8 mm eddy-current proximity measurement systems, part of the 21504 / 21505 / 21508 / 21747 cable family. This variant carries the 080 cable length option, providing 8.00 metres (315 inches) of cable, and the 00 armor option, meaning it is supplied without armor. The combination of a probe with integral lead and an extension cable is designed to achieve a total system length of either five or nine metres from probe tip to Proximitor, giving machine builders flexibility in locating electronics away from the machine casing. Supplied new and original in factory packing with a 12-month factory warranty.

Technical Parameters

• Model: 21747-080-00
• Product Type: Extension Cable
• Cable Length Option: 080 = 8.00 metres (315 inches)
• Armor Option: 00 = Without armor
• System Length: 5 or 9 metres from probe tip to Proximitor (probe integral lead plus extension cable)
• Input Power: -17.5 Vdc to -26 Vdc at 12 mA maximum consumption
• Calibrated Range: 80 mils (2.0 mm), beginning at approximately 10 mils (0.25 mm) from the probe face
• Scale Factor: 200 mV/mil (7.87 V/mm), ±4% when calibrated as a system; within ±9.5% including interchangeability errors
• Linearity: within 0.8 mils (0.02 mm) of a 200 mV/mil straight line as a system; within 2.3 mils (0.06 mm) including interchangeability errors
• Frequency Response: 0 to 10 kHz (0 to 600,000 cpm); -5% at 10 kHz
• Temperature Sensitivity: typically approximately -3.9% change in scale factor at +150°F (+65°C) at 50 mils (1.27 mm) gap
• Operating Temperature (Proximitor): -51°C to +100°C (-60°F to +212°F)
• Operating Temperature (Probe and Extension Cable): -34°C to +177°C (-30°F to +350°F)
• Relative Humidity: to 95%, noncondensing

Parameter Analysis

The performance figures of the 21747-080-00 are specified for the complete measurement loop rather than the cable in isolation. When the probe and cable are calibrated together as a system, the scale factor holds within ±4% of 200 mV/mil and linearity stays within 0.8 mils of a straight line. Allowing for interchangeability errors when mixing components of the same part number widens these bounds to ±9.5% and 2.3 mils respectively — still ample for machinery protection duties. The frequency response covers 0 to 10 kHz (0 to 600,000 cpm), which spans the running-speed and sub-synchronous frequencies of most turbomachinery trains. The 8.00 metre length of this variant suits installations where the Proximitor is mounted in a junction box or electronics room well away from the probe location, within the overall five or nine metre system limit.

Application Scenarios

This extension cable is used wherever an 8 mm eddy-current probe must be connected to its Proximitor: steam and gas turbines, compressors, pumps, motors, fans, and other rotating equipment protected by Bently Nevada proximity systems. The unarmored construction is appropriate for cable runs protected by conduit or cable trays. Where the run is exposed to mechanical abuse, the stainless-steel armored variants of the same cable family provide improved resistance to physical damage and can be ordered instead.

Installation Guide

Plan the cable run so that the probe integral lead plus the extension cable equals the intended total system length of five or nine metres. Route the cable away from pinch points, hot surfaces, and moving parts, and avoid sharp bends at the connectors. Probes and cables of the same length, and Proximitors with the same part number, are completely interchangeable, which simplifies replacement during maintenance. After installation, verify connector seating and confirm the probe gap voltage before returning the train to operation.

Compatibility

The 21747-080-00 matches the 8 mm proximity probe family (21504 / 21505 / 21508 / 21747 series) and the corresponding Proximitors. Because components sharing the same part number are fully interchangeable, this cable can replace an existing 21747-080-00 without recalibration of the loop as long as the system is calibrated as a set. TenBN can supply the complete chain — probe, extension cable, and Proximitor — under consistent part numbers.

Maintenance Advice

During outages, inspect the cable jacket and connectors for cuts, moisture ingress, or loosened couplings, and confirm the cable remains within its -34°C to +177°C operating range in service. The system tolerates relative humidity up to 95% noncondensing. For 8 mm probes, probe operation is not affected by direct contact with air, water, lube oil, ammonium hydroxide, sulfuric acid (10%), MEK, or DMF, but cable runs should still be kept clear of standing fluids and abrasive surfaces.

Procurement Advice

Confirm the exact cable length and armor option digits against your system drawing before ordering, since these define the mechanical fit of the spare. The 21747-080-00 offered here is new and original in factory packing and carries a 12-month factory warranty. TenBN holds this item in inventory for immediate shipment; contact [email protected] for pricing, bulk quantities, and current lead time.

Frequently Asked Questions

How long is the 21747-080-00 extension cable?

The 080 length option provides 8.00 metres (315 inches) of cable, supplied without armor under the 00 armor option.

Which probe systems does this cable fit?

It is part of the 8 mm eddy-current proximity family (21504 / 21505 / 21508 / 21747) and connects the probe to its Proximitor within a five or nine metre total system length.

Are probes, cables, and Proximitors interchangeable?

Yes. Probes and cables of the same length, and Proximitors with the same part number, are completely interchangeable per Bently Nevada system design.

What accuracy does the system achieve with this cable?

Calibrated as a system, the loop holds a 200 mV/mil scale factor within ±4% and linearity within 0.8 mils (0.02 mm); including interchangeability errors the bounds are ±9.5% and 2.3 mils (0.06 mm).

What warranty is included?

The cable is supplied new and original in factory packing with a 12-month factory warranty.