The Bently Nevada 330704-020-100-90-02-00, also cataloged as the 330704 Proximity Probe, operates as a dedicated hardware component for high-temperature shaft vibration and position monitoring within 3300 XL transducer systems. Configured for operation in extreme thermal environments, this probe provides direct physical and electrical execution of eddy-current signal sensing. It converts the distance between the probe tip and the conductive target into a precise voltage signal, ensuring continuous data transmission for rotor dynamics analysis and machine protection platforms without signal degradation under elevated process heat.

Suffix Breakdown & Model Matrix

The 330704-020-100-90-02-00 is a specialized transducer assembly defined by the following configuration parameters:

• 020: Unthreaded length (20 mm)

• 100: Overall case length (100 mm)

• 90: Total length (9.0 meters)

• 02: Connector type (Miniature coaxial)

• 00: Agency approval (Standard)

Hardware Specifications

Mechanical Monitoring & TSI Characteristics

The 330704 series is engineered for high-temperature applications where eddy-current probe scaling must remain stable despite thermal expansion. Accurate rotor dynamics analysis depends on consistent gap voltage validation at the Proximitor sensor output, with -10 VDC targets representing the linear center of the transducer range. To ensure measurement integrity, cross-talk suppression is maintained by using shielded coaxial paths, preventing interference in dense turbine instrument arrays. These probes are specifically calibrated to compensate for temperature-induced sensitivity changes, ensuring the machine protection system accurately interprets shaft motion.

Ordering Info

• 330704 High-Temperature Proximity Probe

• Protective connector caps

• Installation and technical data sheet

• Note: Mounting clamps and extension cables are sold separately to match specific installation housing geometry.

Field Installation Guidelines

• Thermal Management: Ensure the cable routing avoids direct contact with uninsulated steam lines or extreme heat sources exceeding 260 deg C.

• Gap Setting: Use a calibrated feeler gauge to establish the gap; verify the Proximitor voltage corresponds to the -10 VDC nominal center-point before machine startup.

• Torque Constraints: Tighten the locknut to manufacturer specifications to prevent mechanical resonance; avoid over-torquing which can distort the probe housing.

• Grounding: Secure a low-impedance ground path for the probe casing to eliminate signal noise in the monitoring loop.

• Cable Protection: Install the coaxial cable within grounded metallic conduit to provide shielding against electromagnetic interference (EMI).

Frequently Asked Questions

• Q: Can this probe be used in standard 3300 XL systems?

• A: Yes, provided the Proximitor is matched to the high-temperature probe requirements. Verify the scale factor in the monitor configuration.

• Q: Is the 9.0 meter cable length field-adjustable?

• A: No, the cable length is a fixed component of the system impedance; changing the length will invalidate calibration.

• Q: How do I test the probe for high-temperature stability?

• A: Perform baseline gap checks at ambient temperature and verify after thermal stabilization; minor bias shifts are normal but should remain within specification.

• Q: Is the PPS tip resistant to chemicals?

• A: The probe tip is chemically inert and designed to withstand exposure to industrial lubricants and process gases common in turbomachinery.

• Q: Can I use this probe on non-metallic shafts?

• A: No, the eddy-current principle relies on the conductivity of the target shaft; non-conductive targets will not generate a usable signal.

• Q: What is the primary cause of signal loss?

• A: Signal loss is typically caused by physical damage to the cable jacket, connector moisture ingress, or internal coil failure due to excessive shock.

• Q: Does the probe require specialized mounting?

• A: Standard mounting brackets for 8 mm probes are used, but ensure the bracket material is compatible with high-temperature thermal cycling.

• Q: Are the connectors waterproof?

• A: Connectors are not submersible. Install them inside a NEMA-rated junction box to prevent environmental contamination and signal attenuation.