21504-00-16-05-02 Bently Nevada 7200 Series Probe Stock

Product Overview

The 21504-00-16-05-02 is an 8 mm eddy current proximity probe belonging to the legacy Bently Nevada 7200 Series transducer system. Designed for critical machinery monitoring, this sensor measures dynamic vibration and static position on high-speed rotating shafts without physical contact.

Built with standard 3/8-24 mounting threads and a 160 mm total case length, the 21504-00-16-05-02 probe delivers high accuracy across harsh industrial environments. It provides reliable vibration tracking for fluid-film bearing machinery, helping engineering teams prevent unplanned outages and maintain machine health.

Configuration Breakdown

Model code structure for the 21504-00-16-05-02 transducer:

• 21504 — 7200 Series 8 mm Proximity Probe (3/8-24 Thread)
  • -00- Unthreaded Case Length: 0 mm unthreaded sleeve (fully threaded probe casing)
  • -16- Overall Case Length: 160 mm total case body length
  • -05- Cable Length Option: 0.5 meter (20 inches) probe cable (+5 in / -2 in tolerance)
  • -02- Connector Option: Equipped with miniature male coaxial connector (unarmored cable)

Technical Specifications

Installation & Mounting Guidelines

• Port Inspection: Clean machine casing 3/8-24 tapped holes to clear debris prior to thread engagement.
• Gap Setpoint Adjustment: Thread the probe body until reaching approximately -9.0 Vdc bias voltage (~1.27 mm / 50 mils gap) on the Proximitor output terminals.
• Locknut Torquing: Tighten external jam nuts securely against process mounting boss to prevent loosening from machine vibration.
• Cable Routing: Route unarmored FEP lead wire away from sharp metal edges, keeping minimum bend radius above 25.4 mm.
• Connector Protection: Enclose miniature coaxial connectors inside connector protectors to prevent oil ingress and grounding against machine housing.

Field Calibration & Inspection Procedures

• Spindle Micrometer Test: Check gap voltage using a target block on a calibration spindle to verify 200 mV/mil scale factor slope across the 80 mil linear window.
• Continuity Verification: Test lead wire resistance between center conductor pin and outer sheath to confirm probe coil integrity.
• Environmental Checks: Inspect outer cable jackets for physical cuts or thermal degradation during scheduled turnarounds.

System Compatibility & Integration

The 21504-00-16-05-02 probe connects directly to matching 7200 Series extension cables and Proximitor units. The complete system outputs an analog voltage proportional to shaft position, integrating seamlessly with Bently Nevada monitoring racks like the 3300 or 3500 platforms via 3-wire field cabling.

Compliance & Quality Approvals

• Manufacturing Standard: Produced under rigorous Bently Nevada quality control standards.
• Environmental Resistance: Rated for up to 95% non-condensing relative humidity.
• Chemical Immunity: Fully resistant to common industrial solvents, lube oils, and mild acidic atmospheres.

Model Selection & Comparative Analysis

Matching housing depth and cable configuration is essential when selecting 7200 Series hardware. Review these key specification differences between variants:

• Target Model: 21504-00-16-05-02
  • Unthreaded / Case Length: 0 mm unthreaded / 160 mm case length
  • Cable Length: 0.5 meter (20 inches) short probe lead
  • Armor Option: Unarmored coaxial cable (-02)
  • Application: Deep process tapped ports requiring short leads into external junction boxes
• Alternative Variant: 21504-20-32-10-02
  • Unthreaded / Case Length: 20 mm unthreaded / 320 mm case length
  • Cable Length: 1.0 meter (39 inches) extended lead wire
  • Armor Option: Unarmored coaxial cable (-02)
  • Application: Machine housings requiring partial unthreaded shank clearance and longer reach

Selection Guidance: Specify the 21504-00-16-05-02 for standard 160 mm fully threaded tapped holes where 0.5-meter leads connect directly to nearby extension cables. Select the 21504-20-32-10-02 when internal casing obstructions require a 20 mm clearance shank and a 320 mm total body reach.

Packaging & Commercial Terms

• Item Condition: Factory New & Original in genuine manufacturer packaging.
• Warranty Terms: Covered by a 12-Month factory warranty policy.
• Shipping Logistics: Fast global express dispatch via FedEx, UPS, or DHL services.
• Dispatch Lead Time: Ships within 24 to 48 hours following order confirmation.

Industrial Applications & Fault Diagnostics

The 21504-00-16-05-02 probe monitors rotating machinery across critical energy and manufacturing facilities:

• Steam & Gas Turbines: Continuously tracks journal bearing dynamic shaft vibration and axial thrust displacement.
• Boiler Feed Pumps: Detects shaft runout, impeller unbalance, and rotor misalignment early.
• Centrifugal Gas Compressors: Identifies oil whirl, oil whip instabilities, and bearing clearance degradation.
• Large Electric Motors: Monitors shaft eccentricity during startup and steady-state thermal expansion.

Global PLC Spare HUB's Insight

During field maintenance on older power generation plants, our engineering team frequently retrofits legacy monitoring loops using 7200 Series transducers. A common field issue involves installing unarmored probe leads in tight bearing pedestals without proper protection, leading to pinched lead wires during casing reassembly.

On a recent pump station overhaul, technicians replaced damaged sensors with the 21504-00-16-05-02. By slipping protective flexible tubing over the 0.5-meter lead and properly torqueing the jam nuts, the crew restored baseline vibration tracking without signal drift. To preserve scale factor accuracy on legacy systems, always match 7200 Series probes with their correct system cable length and Proximitor tuning.

Frequently Asked Questions (FAQ)

Q: What total system length does a 0.5m probe cable require?

A: A 0.5-meter 21504-00-16-05-02 probe typically pairs with a 4.5-meter extension cable to form a standard 5.0-meter 7200 Series transducer system.

Q: How do I verify if a 7200 probe output is linear in the field?

A: Supply power to the Proximitor (-24 Vdc) and gap the probe away from a steel target using a micrometer fixture. Measure output voltage in 10 mil increments; voltage should change by approximately 200 mV per mil of movement.

Q: Can this unarmored cable version withstand contact with turbine synthetic lube oil?

A: Yes, the 8 mm 21504-00-16-05-02 probe cable uses FEP insulation that resists direct contact with lube oil, water, and common industrial solvents.

Q: What indicates a shorted probe coil during electrical testing?

A: Measuring near zero Ohms resistance between the center pin and outer coaxial conductor indicates an internal short, requiring probe replacement.

Q: How should I choose between fully threaded and unthreaded case options for 21504 probes?

A: Choose Option 00 (0mm unthreaded) when adjusting probe depth through deep threaded ports. Choose unthreaded options (like Option 20) when passing through unthreaded mounting bracket clearance holes before engaging casing threads.

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