Bently Nevada 21747-045-00 Extension Cable

The Bently Nevada 21747-045-00, also cataloged as the 21747 Extension Cable, serves as the primary 21747 interconnection component that transmits signals between the probe and Proximitor sensor across 7200 Series Proximity Transducer System platforms.

Suffix Breakdown & Model Matrix

The 21747-045-00 follows the configuration matrix defined for the 7200 Series platform:

• 21747: Extension Cable for 5 mm and 8 mm Proximity Transducer Systems.
• -045: Cable length (4.5 meters).
• -00: Armor option (None).

Hardware Specifications

Mechanical Monitoring & Eddy-Current Validation

The 7200 Series system detects relative motion between the probe tip and the target through high-frequency eddy-current coupling. The 21747 extension cable maintains the characteristic impedance necessary for the total loop length. When commissioning the system, technicians must perform gap voltage validation; they target -10 VDC at the Proximitor output to ensure the system operates within its linear measurement range. Furthermore, the 7200 series system functions as a matched set. Consequently, the extension cable length must match the original system design to prevent signal attenuation and calibration errors.

Frequently Asked Questions

Q: Can technicians use this 7200 Series extension cable with a 3300 XL series Proximitor?

A: No. 7200 Series components match the impedance of their specific Proximitor and probe family. Mixing 7200 Series cables with 3300 XL equipment will introduce signal non-linearity and cause inaccurate vibration readings.

Q: What defines the “00” armor option, and does it allow for field upgrades?

A: The “00” option signifies that the manufacturer supplied the cable without stainless steel armor. This option prohibits field upgrades; therefore, if the application requires protection against mechanical impact, users must select an armored cable during the initial ordering process.

Field Installation Guidelines

1. Cable Routing: Engineers should route the coaxial cable through dedicated conduits or cable trays to minimize electromagnetic interference (EMI). They must also avoid placing cables near high-voltage power lines.
2. Connector Integrity: Maintenance teams must keep connector interfaces clean and dry. Additionally, they should use protective caps during pull-through operations to prevent debris from fouling the miniature coaxial pins.
3. Strain Relief: Installers need to implement adequate strain relief at the cable junction. This action prevents axial tension from stressing the probe-to-cable or cable-to-sensor connections.
4. Shield Continuity: Ensure the cable shield remains continuous throughout the run. Finally, ground the shield only at the monitoring instrument end to avoid ground loops that inject electrical noise into the TSI network.