Bently Nevada 21504-000-16-05-02 Proximity Probe

21504-000-16-05-02 — Stop the Clock on Your Downtime. Ship Today.

Every hour a turbine or compressor sits idle costs real money — production losses, penalty clauses, idle crew. The Bently Nevada 21504-000-16-05-02 is an 8 mm eddy-current proximity probe from the 3300 XL Series, and we stock it in Xiamen for exactly this scenario: your machine is down, your OEM lead time is 6 weeks, and you need a verified original part on a plane today. We’ve handled this call hundreds of times. We know what you need.

URGENT REQUIREMENT? Contact: [email protected] | WhatsApp: +86 18359268345

Quick Technical Datasheet

Troubleshooting & Replacement Tips

Replacing a 3300 XL proximity probe is not complicated — but getting it wrong means another trip to the machine floor. Here’s what actually matters in the field:

1. Verify the full part number before you pull anything. The suffix structure of 21504-000-16–05–02 encodes probe body length (16 = 25 mm), cable length (05 = 5 m), and connector type (02 = standard). Swapping a -08 cable for a -05 changes your Proximitor® loop impedance and will throw a fault on the 3500 rack immediately. Confirm all three suffix segments match your existing probe before ordering.

2. Gap setting is everything. The 3300 XL 8 mm probe operates in a linear range of 0.25–2.54 mm. Factory default gap for most turbine applications is 1.0–1.5 mm (40–60 mil). Use a calibrated gap tool or a feeler gauge stack — never eyeball it. After installation, verify DC gap voltage at the Proximitor® output: expect approximately −10 to −12 VDC at nominal gap. If you’re reading outside −7 to −18 VDC, recheck your gap before you spin the machine.

3. Common fault codes and what they actually mean:

• OK LED off / Not OK relay energized on 3500/42M: First suspect is an open circuit in the coaxial cable — check the connector at the Proximitor® input for corrosion or a bent center pin. Second suspect is probe tip damage from a rub event. Measure resistance from probe tip to shield: should be open circuit (eddy-current probe, not a contact sensor). Any measurable resistance indicates a shorted probe — replace immediately.
• High vibration alarm with no process change: Check for electrical noise coupling. Ensure the coaxial cable is not routed parallel to power cables. Verify the Proximitor® case is grounded at one point only — ground loops are the #1 cause of phantom vibration readings in turbine halls.
• Intermittent signal dropout: 90% of the time this is the coaxial connector at the extension cable junction. Clean with isopropyl alcohol, inspect the center pin, and apply a thin coat of Bently Nevada-approved connector grease. If the dropout persists after connector service, the probe itself has a hairline crack in the coil winding — replace the probe.
• Scale factor drift over time: The 3300 XL probe is factory-calibrated to 7.87 V/mm on AISI 4140 steel. If your target shaft is a different alloy (e.g., Inconel, titanium), the effective scale factor will differ by 5–20%. This is not a probe fault — it requires a target material calibration at the Proximitor® level. Document the corrected scale factor in your DCS configuration.

4. Torque the lock nut correctly. Over-torquing the probe body distorts the coil geometry and permanently shifts the scale factor. Refer to the Bently Nevada installation drawing for your specific bracket — typically 14–20 N·m depending on body material. Use a calibrated torque wrench, not an impact driver.

5. No firmware to match on the probe itself — the 21504-000-16-05-02 is a passive sensor. Firmware compatibility concerns apply to the 3500 rack cards and the System 1 software version, not the probe. However, if you are replacing a probe in a system running System 1 Evolution, verify that the channel configuration in the software reflects the correct probe model and cable length for accurate gap calculation.

Reliability in Harsh Conditions

The 3300 XL probe body is constructed from 316 stainless steel with a PEEK (polyether ether ketone) tip housing — a material choice that is not accidental. PEEK maintains dimensional stability from cryogenic temperatures to 250 °C continuous, resists hydrocarbon fluids, H₂S, and steam condensate without swelling or cracking. In offshore compressor trains where salt-laden air and humidity are constant, the stainless body shows no galvanic corrosion after years of service.

The integral coaxial cable uses a fluoropolymer (PTFE) jacket rated for continuous immersion in turbine lube oil — a real-world condition in bearing housings where oil mist is unavoidable. The cable is also rated to IEC 60068-2-6 for sinusoidal vibration up to 15 g across 10–2000 Hz, which covers the full excitation spectrum of any rotating machine you are likely to encounter in power generation or petrochemical service.

Eddy-current sensing has an inherent reliability advantage over contact-type sensors: there is no wear mechanism. The probe tip never touches the shaft. Mean time between failures for 3300 XL probes in clean installations exceeds 10 years. The failure modes that do occur — coil winding cracks, connector corrosion, cable jacket abrasion — are all detectable through routine signal quality checks without removing the probe from service.

Every unit we ship has been stored in climate-controlled conditions in original ESD-safe packaging. We do not sell probes that have been installed, removed, and repackaged. If the seal is intact and the part number matches, you are getting a factory-fresh sensor.

Global Express Logistics

Our warehouse is located in Xiamen, Fujian Province — one of China’s primary export hubs with direct access to Xiamen Gaoqi International Airport and daily consolidated freight departures to DHL and FedEx international gateways.

Standard express timeline (DHL / FedEx International Priority):

• Order confirmed before 14:00 CST → same-day dispatch
• Southeast Asia (Singapore, Thailand, Malaysia): 2–3 business days door-to-door
• Middle East (UAE, Saudi Arabia, Qatar): 3–4 business days
• Europe (Germany, Netherlands, UK): 3–5 business days
• North America (USA, Canada): 4–6 business days
• Australia / New Zealand: 3–5 business days

We prepare commercial invoices with accurate HS codes (HS 9031.80 for proximity measurement instruments) and country-of-origin documentation to minimize customs clearance delays. For projects requiring formal import permits or end-user certificates, contact us 24 hours in advance and we will coordinate the paperwork.

For genuine emergencies — machine down, production at zero — tell us when you contact us. We will prioritize your shipment in the pick queue and provide a tracking number within 2 hours of payment confirmation. We have shipped to active offshore platforms, remote mining sites, and landlocked power stations. If there is a courier route, we will find it.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
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