Product Overview
The Bently Nevada 330191-00-70-20-00 is a 3300 XL 8 mm ETR proximity probe designed for critical rotating machinery protection. This model features a 7-inch overall case length and a 2.0-meter total probe length, with a 3/8-24 UNF thread and no armor. The 330191-00-70-20-00 incorporates patented TipLoc and CableLoc technologies to prevent common probe failures such as tip detachment and cable pull-out, ensuring reliable operation in harsh industrial environments.
Technical Specifications
| Parameter |
Value |
| Power Supply |
-17.5 Vdc to -26 Vdc (nonincendive); -23 Vdc to -26 Vdc with barriers; 12 mA max consumption |
| Supply Sensitivity |
< 2 mV change in output voltage per volt change in input voltage |
| Output Resistance |
50 Ω |
| Nominal Probe DC Resistance (RPROBE) at 2.0 m |
7.88 ± 0.50 Ω |
| Probe Tip Material |
Polyphenylene sulfide (PPS) |
| Probe Case Material |
AISI 303 or 304 stainless steel |
| Standard Cable |
75Ω triaxial, FEP insulated; lengths: 0.5, 1, 1.5, 2, 3, 5, 9 m |
| Extended Temperature Range Cable |
75Ω triaxial, PFA insulated; lengths: 0.5, 1, 1.5, 2, 5, 9 m |
| Armor (optional) |
Flexible AISI 302 or 304 SST with FEP outer jacket |
| Tensile Strength (Max Rated) |
330 N (75 lbf) probe case to lead; 270 N (60 lbf) at lead to extension cable connector |
| Connector Material |
Gold-plated brass or gold-plated beryllium copper |
| Maximum Connector Torque |
0.565 N·m (5 in·lbf) |
| Probe Case Thread (Max Thread Engagement) |
3/8-24, 0.563 in |
| Weight |
323 g/m (11.4 oz/ft) |
| Temperature Classification (EPL Ga/Gc) |
T1 (-55°C to +232°C) to T5 |
Why This Probe Prevents Common Failures
The Bently Nevada 330191-00-70-20-00 uses a patented TipLoc molding method that creates a robust bond between the probe tip and body, eliminating tip separation. The CableLoc design provides 330 N (75 lbf) pull strength at the probe case to lead connection, preventing cable pull-outs during installation or vibration. An optional FluidLoc cable option stops oil leakage through the cable interior, a common issue in lubricated machinery.
Industry Applications
This 330191-00-70-20-00 probe is ideal for vibration monitoring on steam turbines, centrifugal compressors, and large pumps. The 8 mm diameter provides a thicker PPS encapsulation for enhanced ruggedness compared to 5 mm probes. In high-temperature environments (up to +232°C for T1 classification), the probe maintains accurate measurement without drift.
Installation Guidance
When installing the 330191-00-70-20-00, ensure the 3/8-24 UNF thread is engaged to a maximum of 0.563 in. Use a torque wrench on the connector to not exceed 0.565 N·m. For one-meter systems, no extension cable is required. If using barriers, supply voltage must be between -23 Vdc and -26 Vdc to maintain linear range. Operation at more positive than -23.5 Vdc may reduce linear range.
Maintenance Tips
Inspect the probe cable for cuts or kinks regularly. The Viton O-ring seal prevents differential pressure leakage but is not pressure tested—avoid over-tightening. Replace the O-ring if any oil seepage is noticed. Keep the probe tip clean; PPS is resistant to most chemicals but avoid abrasive cleaners.
Troubleshooting Common Issues
If output voltage is erratic, verify supply voltage is within -17.5 Vdc to -26 Vdc (nonincendive) or -23 Vdc to -26 Vdc with barriers. Check RPROBE at the probe head: it should be 7.88 ± 0.50 Ω for the 2.0 m length. A high resistance indicates a damaged cable. Confirm the connector is torqued to 0.565 N·m. If the system uses a barrier, ensure the barrier is compatible with the probe entity parameters, which are met when using Bently Nevada extension cables and a Bently Nevada Proximitor.