Configured for non-contacting vibration and displacement measurement in machinery protection systems, the Bently Nevada 21504-16-32-10-02 (21504 Proximity Probe) provides direct physical/electrical execution.

Suffix Selection Matrix

The technical options of this 7200 Series proximity probe are defined by the following suffix codes:

• 21504: Base model designation for the 5 mm / 8 mm Standard Mount Proximity Probe (3/8-24 UNF threads).
• -16: Configures a minimum unthreaded length of 1.6 inches.
• -32: Configures a minimum case length of 3.2 inches.
• -10: Selects a total cable length of 1.0 meter (39 inches), with a tolerance of +0.25 meter, -0.10 meter (+10 inches, -4 inches).
• -02: Terminates the cable with a miniature male coaxial connector.

Hardware Specifications

Eddy-Current Probe Scaling and Rotor Dynamics Integration

The 21504-16-32-10-02 probe relies on eddy-current probe scaling to measure the proximity of a target shaft. This high-frequency physical interaction provides real-time tracking of rapid shaft oscillations. To ensure correct integration with rotating machinery, a gap voltage validation is required during field setup. By adjusting the physical mechanical gap until the system output registers the nominal -10 VDC target, the probe is centered in its linear operating region.

This precise positioning is critical for recording rotor dynamics parameters, such as radial shaft vibration and axial thrust position, while preventing signal saturation on the associated 7200 Series monitor modules.

Ordering Info

• 1 x Bently Nevada 21504-16-32-10-02 Proximity Probe
• 2 x 3/8-24 Locknuts
• 1 x Thread protective cap

Field Installation Guidelines

• Thread Mechanical Clearances

  Ensure the 3/8-24 UNF threads on the probe case and mounting bracket are clean and free of burrs. Always maintain the minimum unthreaded length of 1.6 inches to clear the interior diameter of the mounting hole and prevent damage to the probe tip.

• Connector Protection

  The miniature male coaxial connector on the probe cable is highly sensitive to moisture and dirt. Ensure the connector body remains clean during routing, and install a protective sleeve or sealing boot after mating it with the extension cable.

• Cable Routing Restrictions

  Do not bend the coaxial cable to a radius sharper than 25.4 mm (1.0 inch). Securing the cable with plastic ties prevents mechanical wear caused by high-frequency machinery casing vibration.

Frequently Asked Questions

• How is the target gap voltage validated during the installation of this 7200 series probe?

  Hook a digital multimeter to the Proximitor output terminals and adjust the physical position of the probe until the voltage reads -10 VDC.

• What happens if the probe's unthreaded length option is selected incorrectly?

  Selecting an unthreaded length shorter than the hole depth can cause the threaded portion of the case to bottom out, damaging the threads.

• Is this probe compatible with the newer 3300 XL Proximitor sensors?

  No, the 7200 Series probe has different electrical characteristics and scaling parameters, making it incompatible with 3300 XL Proximitor systems.

• What is the maximum temperature rating of the 21504 coaxial cable?

  The cable jacket and internal insulators are constructed to withstand continuous operation in environments up to +177 deg C.

• How can signal cross-talk be suppressed when multiple probes are installed together?

  Maintain a minimum physical separation distance of at least 40 mm between probe tips to prevent overlapping of the eddy-current fields.

• Can this probe be connected directly to a monitoring monitor without an extension cable?

  No, the probe's 1.0 meter cable must be matched with a proper 7200 series extension cable to reach the required system length.

• What is the standard target material calibration for this 7200 series transducer?

  The system is calibrated for a flat, AISI 4140 steel target; alternative metals require custom scale factor calibration.

• How should the miniature male coaxial connector be cleaned if contaminated?

  Use a dry, lint-free swab or clean electrical contact cleaner to remove dirt, ensuring the connector is dry before mating.