BENTLY 330400-02-05 | 3300 XL Proximity Probe – 5 mm

Description

Product Introduction

The vibration reading jumps. The operator calls. You walk to the machine and see the probe cable is frayed where it exits the junction box. That’s the 330400-02-05. It’s dead.

The BENTLY 330400-02-05 is the long‑cable version of the 3300 XL proximity probe. Five meters of cable instead of the standard two. It’s for machines where the junction box is far from the probe location—compressors, large turbines, generator bearing housings. The probe itself is the same 5 mm tip. The cable is the difference.

I’ve replaced these in gas turbines, steam turbine pedestals, and compressor bearing housings. The failure mode is almost always the cable—chafed, pinched, or cut. The fix is swapping the probe. One bolt, one cable, one gap setting. Thirty minutes, if the spare is on the shelf and you have to thread five meters of cable through the conduit.

Key Technical Specifications

Quality Inspection Process (SOP Transparency)

Probes with long cables are more prone to damage. We test the cable hard.

1. Incoming Verification
   This batch came from a Bently authorized distributor’s final 3300 stock. Sealed boxes. Serial numbers traceable to 2015–2018 production.
2. Visual Inspection
   First: the probe tip. No scratches, no dents, no wear. Next: the cable—roll it between your fingers for the full 5 meters. Feel for flat spots, kinks, or cuts. Look for pinch marks. Check the connector. Threads should be clean, no corrosion.
3. Electrical Test
   We test the 330400-02-05 with a calibrated 3300 XL Proximitor and a precision target stand. Procedure:
   • Connect probe to Proximitor, power up at –24 VDC
   • Position target at 1.5 mm gap (center of linear range)
   • Measure output voltage: should be –10.0 V ±0.1 V
   • Sweep target from 0.25 mm to 2.25 mm, record voltage at 0.25 mm increments
   • Verify linearity: voltage change should be 7.87 V/mm ±0.1 V/mm
   • Cable flex test: bend cable at 90° at three points (near probe, middle, near connector), watch for output jumps
4. Insulation Test
   Measure resistance between center conductor and shield. Should be >10 MΩ. Any leakage fails.
5. Final QC & Packaging
   Passed probes go back in anti‑static bags, then bubble wrap, then a carton with QC sticker showing test date, gap voltage, and linearity check.

Field Replacement Pitfalls

Long cables mean more places to make mistakes.

1. Cable routing.
   Five meters of cable gives you lots of opportunity to pinch it. I’ve seen a plant install a new probe, run the cable through a conduit with sharp edges, and cut the insulation. The probe worked for a week, then started giving intermittent signals. The cable was the problem. Use a cable pulling lubricant and check the conduit for burrs.
2. ❌ Gap setting.
   The probe needs a specific gap—usually 1.5 mm at center of linear range. I’ve seen a plant install a new probe, set the gap by feel, and wonder why the vibration reading was 50% off. Use a feeler gauge or set the gap with the Proximitor.
3. Connector torque.
   The Microdot connector needs to be tight—finger tight plus a quarter turn. I’ve seen a plant with intermittent vibration readings that traced back to a loose connector. The probe was fine. The connection was the problem.
4. Cable extension.
   If you need more than 5 meters, you have to use a Bently extension cable—the right type and length. I’ve seen a plant add a 10‑meter extension with the wrong cable and wonder why the vibration readings were noisy. The probe was fine. The extension was the problem.
5. Probe interference.
   Two probes on the same shaft can interfere if they’re too close—less than 25 mm between tips. I’ve seen a plant with cross‑talk between X and Y probes that made the orbit look like a football. The probes were fine. The spacing was wrong.

Get these five right and you’ll cut rework time by 90%.

New Original vs. Refurbished: Why It Matters

“New Original (New Surplus)” means this BENTLY 330400-02-05 was built by Bently, never installed, and never repaired. The cable is fresh. The probe tip is pristine. The calibration is factory‑fresh.

Refurbished proximity probes are risky. The cable is the weak point. A refurb probe may have a cable that’s been bent, pinched, or heat‑cycled. It will pass a continuity test but fail in the field after a few months. I’ve seen a plant buy a refurb probe that worked for six months, then started giving intermittent signals. The downtime cost was ten times the probe price.

What we provide:

• Traceable serial number (matches Bently production records)
• Full linearity test (0.25–2.25 mm in 0.25 mm steps)
• Gap voltage measurement (–10.0 V ±0.1 V)
• Cable flex test at three points
• Insulation test (>10 MΩ)
• Original anti‑static bag (if available) or fresh bag with QC seal
• 12‑month warranty

Pricing context:
Our price sits above the cheapest used listings. It’s also below what a new probe would cost if Bently still made them. You’re paying for the test, the warranty, and the certainty that the cable isn’t going to fail next month.

Performance Benchmarks & Test Results

All tests performed with 3300 XL Proximitor, 25 °C ambient.

Thermal performance note:
At 150 °C (probe tip), the sensitivity drops about 2%. Still within spec. The cable jacket is rated for 177 °C. If your machine runs hotter than that, you need the high‑temp version. This one will cook.

One more thing from the field:
The 330400-02-05 has a small dot on the probe tip. That’s the center of the coil. When you set the gap, you measure from that dot to the shaft. I’ve seen a tech set the gap from the probe body, which is 3 mm further out. The probe was in the right spot. The gap was wrong. The readings were off. Measure from the dot. It matters.

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