Precision Sensing in Restricted Spaces

The Bently Nevada 21504-000-08-10-02 5mm Proximity Probe represents a specialized solution for machinery protection where mounting space is at a premium. While standard 8mm probes offer wider linear ranges, this 5mm variant provides high-accuracy non-contacting vibration and position measurements in tight geometric configurations, such as small centrifugal compressors, pumps, and high-speed gearboxes. By utilizing eddy current technology, the probe delivers real-time data on shaft radial vibration and axial position, ensuring that even the most compact rotating assets remain within safe operational limits. Its robust design ensures it withstands the aggressive lubricating oils and high-temperature cycles common in industrial heat rejection and compression loops.

Transducer Configuration & Suffix Logic

21504 - 5mm Proximity Probe Series

Defines the specialized 5mm tip diameter probe, specifically designed for small-target applications where standard sensors would suffer from excessive side-view interference.

000 - Unthreaded Length (Dimension A)

Specifies a 0.0-inch (0 mm) unthreaded length. This fully threaded body provides maximum mounting flexibility, allowing the probe to be secured at any depth within the bearing housing or bracket.

08 - Overall Case Length (Dimension B)

Indicates a 0.8-inch (20.3 mm) total case length. This compact, short-body design is ideal for extremely shallow mounting environments where external clearance is non-existent.

10 - Total Length

Designates a 1.0-meter (3.3 feet) integrated lead cable. This cable must be paired with the correct extension cable to complete the 5.0m or 9.0m system electrical length.

02 - Connector and Cable Option

Features a miniature coaxial connector with a standard cable. The connector is engineered for high-frequency signal stability and resists loosening under sustained industrial vibration.

Critical Technical Specifications

Field Commissioning and Setup Guide

Correct mechanical gapping is paramount for the 5mm probe due to its narrower linear range of 50 mils compared to standard probes. Engineers must utilize a calibrated voltmeter to set the gap voltage—typically to -10.0 VDC at the Proximitor output—ensuring the probe sits precisely in the center of its linear region. Because the 21504 utilizes a 1/4-28 UNF thread, technicians must exercise caution not to over-torque the mounting nut; a maximum torque of 2.3 N·m (20 in·lb) prevents damage to the small-diameter stainless steel threads. Always maintain a clean, dry connection at the coaxial junction to prevent signal drift.

Strategic Engineering Advantages

The 21504-000-08-10-02 excels in environments where precision cannot be sacrificed for size. Its high-frequency response allows for the detection of high-order harmonics in small, high-speed rotors, providing a level of diagnostic detail that general-purpose sensors miss. The probe integrates seamlessly with Bently Nevada 3500/42M monitors and high-speed DCS layers like Honeywell Experion PKS. Furthermore, its PPS-filled tip provides a hermetic seal against fluid ingress, ensuring long-term stability even when submerged in pressurized oil environments.

Logistics and Order Fulfillment

Delivery time: 3-5 days when payment finish, BY DHL/FEDEX/UPS.

Every probe is packaged in anti-static industrial packaging with a dedicated tip protector to ensure the ceramic-filled sensing face arrives in factory-calibrated condition.

Proximity System FAQs

Q1: Can I use this 5mm probe with a 3300 XL 8mm Proximitor?

A1: No. The 5mm probe requires a specific Proximitor calibrated for its electrical characteristics. Using an 8mm Proximitor will result in incorrect scale factors and non-linear vibration data.

Q2: What is the benefit of the 0.8-inch short case length?

A2: This short length allows the probe to be mounted in compact gearboxes or small motor housings where a standard 2.0-inch probe would physically interfere with other internal components or the outer enclosure.

Q3: How do I handle the 1.0-meter lead cable during installation?

A3: The lead should be routed through a protective conduit or secured to the machine frame. Ensure the bend radius does not drop below 25.4 mm (1.0 inch) to prevent damage to the internal coaxial shielding.