Configured for signal transmission in mechanical monitoring systems, the Bently Nevada 21747-045-00 (21747 Extension Cable) provides direct electrical connectivity between proximity probes and proximal monitoring instrumentation. This hardware component maintains the high-frequency impedance characteristics required for accurate signal propagation within machine protection networks.

Configuration Characteristics

The 21747-045-00 is a specialized coaxial extension cable defined by:

• 21747: Base model for standard 3000 series extension cable.

• 045: Cable length of 4.5 meters.

• 00: Connector and configuration option (Standard).

Hardware Specifications

Signal Integrity and Cross-Talk Suppression

The 21747 extension cable is engineered to match the impedance of the transducer system, which is required to prevent signal reflection that could corrupt vibration data. In high-density machine installations, maintaining proper signal path integrity is necessary for effective cross-talk suppression. Technicians must ensure that coaxial routing avoids proximity to high-voltage AC lines or electromagnetic noise sources. Any impedance mismatch introduced by damaged connectors or unauthorized cable splices directly impacts the "Gap Voltage" stability, leading to inaccurate shaft centerline measurements and invalid orbital data in machine protection platforms.

Ordering Info

• 21747-045-00 Extension Cable

• Protective connector caps (pre-installed)

• Technical specification sheet

Field Installation Guidelines

• Routing: Install cables within dedicated, grounded metallic conduits to provide shielding against external electromagnetic interference.

• Bend Radius: Adhere to a minimum bend radius of 2.5 cm to prevent damage to the internal dielectric and signal conductor.

• Connector Sealing: Utilize moisture-resistant boots at connections if the environment involves high humidity or oil mist exposure.

• Termination: Ensure connectors are torqued finger-tight; overtightening with pliers can damage the connector threads and internal pin alignment.

Logistics and Handling

• Delivery time: 3-5 days when payment finish.

• Dispatched via DHL/FEDEX/UPS.

• Components are sealed in anti-static industrial packaging to prevent electrostatic damage and mechanical deformation during transit.

Frequently Asked Questions

• What material targets are supported? As this is a passive extension cable, it does not interact directly with the target. It supports systems calibrated for AISI 4140 steel. Signal accuracy remains dependent on the probe-to-target material calibration established at the transducer level.

• What is the probe sensitivity? The cable does not determine sensitivity; however, it is designed to transmit signals with the standard 8 mV/µm (200 mV/mil) sensitivity utilized by compatible Bently Nevada systems.

• How often should calibration be verified? Verification of the cable's resistance and insulation integrity should occur during scheduled machine outages or if the monitoring system exhibits persistent "Gap Voltage" errors.

• Can the probe operate in hazardous environments? This cable is compatible with systems installed in hazardous areas provided that the entire loop, including probes and isolators, adheres to site-specific intrinsic safety control drawings.

• What extension cables are compatible? Only Bently Nevada cables matching the specific system's impedance requirements (75 Ohm) should be utilized. Mixing cable types will result in signal attenuation and erroneous vibration data.

• What causes unstable gap voltage? Instability is often caused by cable degradation, loose or contaminated connectors, or ground loops created by improper conduit grounding.

• How is probe health tested? Health is tested by measuring the loop resistance and verifying the signal output at the monitoring end of the cable using a calibrated signal generator or by static gap measurement.

• What is the expected service life? Service life is subject to the thermal and mechanical duty cycle of the installation site. Under steady-state conditions, the cable is intended for continuous, long-term operation within its rated temperature range.