330930-065-00-05 | Bently Nevada | Extension Cable

The Bently Nevada 330930-065-00-05, also cataloged as the 3300 XL Extension Cable, operates as a dedicated hardware component for signal transmission between proximity probes and monitoring instrumentation within machinery protection systems.

Hardware Specifications

Rotor Dynamics and Signal Integrity

The 3300 XL transducer chain requires precise impedance matching to maintain the integrity of eddy-current probe scaling. This extension cable is engineered to maintain a characteristic impedance of 75 Ohm, which is required to minimize signal reflections that could otherwise result in erroneous gap voltage readings. Maintaining the electrical continuity of the coaxial path is essential for accurate rotor position and vibration data acquisition. When integrating these cables, verify that the total length—inclusive of the probe lead and extension cable—aligns with the system calibration requirements to ensure the output remains within the linear range of the -10 VDC target.

Frequently Asked Questions

Q: Can the 330930-065-00-05 cable be field-terminated or shortened?

A: No. Any modification to the coaxial cable length or connector assembly alters the electrical capacitance and resistance of the transducer system. This invalidates the factory calibration and leads to measurement errors.

Q: How does cable length affect the gap voltage?

A: The transducer chain is a matched system. Increasing the length adds capacitance, which can shift the operating point of the proximity sensor. Always verify the gap voltage at the monitor terminal after installation to ensure it stays within the required -10 VDC target.

Field Installation Guidelines

• Routing: Route the extension cable through dedicated conduit or instrument trays. Maintain separation from high-voltage AC power lines to avoid induced noise on the low-level signal.
• Connections: Ensure all coaxial connectors are hand-tightened to prevent moisture ingress. Do not use pliers or other metal tools, as these can damage the connector threads and the connector seal.
• Grounding: To prevent ground loops, the cable shield must be continuous and grounded only at the terminal housing or monitor side, as specified by the system installation manual.
• Bend Radius: Observe a minimum bend radius of 25 mm during installation to prevent mechanical fatigue of the FEP jacket and the inner conductor.