Product Overview

The Bently Nevada 330880-28-25-061-01-02 is a PROXPAC XL Proximity Transducer with a 2.5 inch standoff adapter. This unit provides reliable shaft vibration and position measurements for rotating machinery. The 330880-28-25-061-01-02 includes a 3300 XL 8 mm probe with multiple approvals. Engineers often select this model when hot machine cases require extra clearance. Additionally, the standoff adapter moves the housing away from high-temperature surfaces. Consequently, this design protects the electronics and extends sensor life. The 61 mm probe penetration suits many standard industrial applications.

Technical Specifications

Measurement & Performance

This transducer offers a linear range of 2 mm (80 mils). Specifically, the linear range starts at 0.25 mm from the target. It then extends from 0.25 mm to 2.3 mm (10 to 90 mils). As a result, the output voltage spans approximately -1 Vdc to -17 Vdc. For optimal results, the recommended gap setting is 1.27 mm (50 mils).

Additionally, the Incremental Scale Factor (ISF) is 7.87 V/mm (200 mV/mil). This value includes a ±5% interchangeability error. The system measures this over the 80 mil linear range. Furthermore, the temperature range for this measurement is 0 °C to +45 °C. Meanwhile, the Deviation from Straight Line (DSL) stays less than ±0.025 mm (±1 mil).

Frequency Response & Resolution

The frequency response operates from 0 to 10 kHz. Consequently, the signal drops by only -3 dB at the high end. Notably, this performance includes up to 305 metres of field wiring. For reference, the minimum target size is 15.2 mm (0.6 inches) diameter. Likewise, the minimum shaft diameter is 50.8 mm (2.0 inches). Therefore, these parameters ensure accurate readings on standard machinery.

Standoff Adapter & Probe Penetration

This model includes a 2.5 inch standoff adapter (option 25) . The standoff moves the housing body away from the mounting surface. Consequently, this feature protects the electronics from radiated heat. The probe penetration (C dimension) is 61 mm (061) . When combined, the standoff plus penetration offers flexible mounting depth. Therefore, this assembly works well on turbines with insulated casings.

Probe & Cable Details

The assembly contains a 3300 XL 8 mm probe with approval option 28. The probe tip material is Polyphenylene Sulfide (PPS) . Meanwhile, the probe case uses AISI 304 stainless steel. The probe cable length is 1 metre of 75 Ω triaxial type. Additionally, the cable uses FEP (fluoroethylene propylene) insulation. A gold-plated brass ClickLoc connector terminates the cable end. Finally, the probe tensile strength reaches 330 N (75 lbs) between cable and case.

Housing & Mechanical Construction

The housing uses UV-resistant glass-reinforced PPS thermoplastic. This material contains conductive fibers for static dissipation. The sleeve and retaining chain use AISI 304 stainless steel. In contrast, the outer sleeve and retaining screws use AISI 303 stainless steel. The sleeve O-ring is made of Neoprene. Similarly, the grounding liner and retaining plate use AISI 304 stainless steel. For vibration control, the isolation uses extra soft cellular silicone. Finally, the lid label is gloss radiant white polyester.

Torque Specifications

For secure assembly, the retaining nut torque is 29.5 N·m (260 in·lb) . Meanwhile, the probe sleeve locknut torque is 39.3 N·m (350 in·lb) . Therefore, follow these values exactly to avoid damage. Otherwise, over-torquing may strip threads or crack the housing.

Housing Strength & Impact Ratings

The housing supports 912 N (205 lbs) of force. This force applies 38 mm from the unsupported end. However, the cover must be fastened with the grounding liner installed. Impact strength meets BASEEFA certification for 4 Joule impacts. Notably, the device withstands impacts at -39 °C and +115 °C. Additionally, CSA verified a 7 Joule impact at room temperature. As a result, the housing carries an IP66 rating verified by BASEEFA report T07/0709.

Environmental Limits & Power

The probe operates from -51 °C to +177 °C (-60 °F to +350 °F) . However, do not expose the probe below -34 °C without caution. Cold temperatures may cause premature failure of the pressure seal. Regarding power, the supply requires -17.5 Vdc to -26 Vdc without barriers. With barriers, use -23 Vdc to -26 Vdc. Consequently, operation above -23.5 Vdc reduces the linear range. Moreover, supply sensitivity stays less than 2 mV change per volt change. Finally, output resistance is 50 Ω.

Field Wiring & Fittings

For field connections, use 0.2 to 1.5 mm² (16 to 24 AWG) wiring. Bently Nevada recommends 3-conductor shielded triax cable. Additionally, use tinned field wiring for best corrosion resistance. The maximum wiring length is 305 metres (1,000 feet) between the proximitor and monitor. However, longer cables may reduce high-frequency response.

The fittings option (01) includes one 3/4-14 NPT fitting and two plugs. This configuration allows one conduit connection while sealing the second port. Therefore, you have flexibility for single-entry wiring.

Installation Guide

Follow these steps to install the Bently Nevada 330880-28-25-061-01-02 properly. First, prepare a clean mounting surface on the machine case. Next, screw the 2.5 inch standoff adapter into the mounting hole. Apply thread sealant to prevent leakage. Then, tighten the standoff to 29.5 N·m.

After that, mount the housing onto the standoff adapter. Install the one 3/4-14 NPT fitting into one housing port. Then, install the two plugs into the remaining ports. Subsequently, adjust the probe to the 61 mm penetration setting. Set the air gap to 1.27 mm (50 mils) from the shaft surface.

Next, tighten the retaining nut to 29.5 N·m. Also tighten the probe sleeve locknut to 39.3 N·m. For wiring, connect the field wiring using 16 to 24 AWG triax cable. However, keep the total wiring length under 305 metres.

Then, connect the power supply between -17.5 Vdc and -26 Vdc. Verify the voltage does not exceed -23.5 Vdc if you need full linear range. After that, test the output voltage. At 1.27 mm gap, expect approximately -10 Vdc. Finally, secure the housing lid and verify the IP66 seal.

Package Contents

• One Bently Nevada PROXPAC XL Proximity Transducer (Model 330880-28-25-061-01-02)

• One 3300 XL 8 mm probe with multiple approvals (option 28)

• One 2.5 inch standoff adapter (option 25)

• One 1-metre triaxial cable with FEP insulation

• One 3/4-14 NPT fitting and two plugs (option 01)

• One gold-plated brass ClickLoc connector (pre-attached)

• One mounting sleeve with locknut

• One grounding liner and retaining plate

• One vibration isolation pad

• Installation instruction sheet

Frequently Asked Questions (FAQ)

1. Why does the 330880-28-25-061-01-02 include a standoff adapter?
The 2.5 inch standoff adapter moves the housing away from hot machine surfaces. Therefore, it protects the electronics from radiant heat damage. This feature is essential for turbines and compressors with high casing temperatures.

2. What is the probe penetration of the 330880-28-25-061-01-02?
The probe penetration (C dimension) is 61 mm (061) . When combined with the 2.5 inch standoff, the total extension increases accordingly. Always verify internal clearances before ordering this model.

3. Can I use this Bently Nevada transducer in wet environments?
Yes, the housing has an IP66 rating verified by BASEEFA. Consequently, it resists powerful water jets and dust ingress. Thus, it is suitable for outdoor or wash-down areas.

4. What approvals does the probe option 28 carry?
The 3300 XL 8 mm probe with option 28 carries multiple agency approvals. These include CSA, ATEX, and IECEx for hazardous locations. Therefore, contact Bently Nevada for the complete certification list.

5. How does the fittings option 01 differ from other options?
Option 01 provides one fitting and two plugs. This suits installations with only one conduit entry. In contrast, option 02 provides two fittings for dual-entry wiring. Choose based on your field wiring layout.