The Bently Nevada 21505-00-28-05-02 serves as the primary 21505 Proximity Probe utilized to execute noncontacting static and dynamic displacement measurements across 7200 Series Proximity Transducer Systems platforms.

Suffix Nomenclature Breakdown

The modular options for the 21505-00-28-05-02 proximity probe are designated as follows:

• 21505: Base model series for the 7200 Series 8 mm Proximity Probe (standard mount, 3/8-24 UNF thread).

• -00: Unthreaded case length of 0.0 in.

• -28: Overall case length of 2.8 in.

• -05: Total cable length option of 0.5 m (20 in).

• -02: Equipped with a miniature male coaxial connector.

Hardware Specifications

Eddy-Current Probe Scaling and Rotor Dynamics Integration

The 21505-00-28-05-02 probe drives high-frequency eddy-current probe scaling when coupled with a 7200 Series Proximitor Sensor. The probe coil projects an RF field into the target area, converting gap distance changes into continuous voltage variations. This electromagnetic loop tracking provides real-time data on complex rotor dynamics, including radial shaft vibration and axial thrust position.

To establish proper measurement scaling, the gap voltage validation must be performed during physical installation. By adjusting the probe's depth until the Proximitor output measures -10 VDC, the system is centered within its 2.0 mm linear range. Correct physical alignment minimizes electrical distortions and achieves cross-talk suppression between adjacent probes installed on the same machinery plane.

Ordering Info

• 1 x Bently Nevada 21505-00-28-05-02 Proximity Probe

• 2 x Hex locknuts for standard mounting

Field Installation Guidelines

• Verifying Probe Side Clearance

  Maintain a minimum radial side clearance of 8.9 mm (0.35 in) between the probe tip and any surrounding metal surfaces to prevent interference with the electromagnetic field.

• Routing and Cable Protection

  Avoid routing the 0.5 m integrated coaxial cable near high-voltage lines. Ensure the cable bend radius does not drop below 25.4 mm (1.0 in) to prevent internal conductor damage.

• Connector Ground Isolation

  The miniature male coaxial connector must remain electrically isolated from the machine housing. Slip a protective insulating sleeve over the connection point during installation.

Frequently Asked Questions

• How is the target gap voltage validated during installation?

  Adjust the probe depth in the mounting thread until the DC voltage at the Proximitor output reads -10 VDC.

• What occurs if the probe tip is installed too close to surrounding metal?

  Surrounding metal within 8.9 mm of the tip will distort the RF field, causing calibration errors.

• Is this probe compatible with a 3300 XL Proximitor?

  No, this legacy 7200 series probe must be paired with a 7200 series Proximitor and extension cable.

• What target material is required for the 200 mV/mil scale factor?

  The standard calibration curve is matched to AISI E4140 steel; other alloys require custom scaling.

• What is the temperature limit for the probe tip during operation?

  The probe tip and cable are rated to operate in temperatures ranging from -51 to +100 deg C.

• Can the coaxial connector be exposed directly to moisture?

  No, the coaxial connection must be protected with an insulating sleeve or housed in a junction box.

• Does this probe support live hot-swapping under loop power?

  Yes, but disconnecting the probe will cause the monitoring monitor channel to report a "Not OK" fault.

• What happens if the cable bend radius is less than 25.4 mm?

  Bends tighter than 25.4 mm degrade the coaxial impedance, generating noise in the vibration signal.