Bently Nevada 330850-90-00 3300 XL 25 mm Proximitor, 9 m Panel

330850-90-00: 3300 XL 25 mm Proximitor Sensor, 9.0 m system, panel mount

The Bently Nevada 330850-90-00 is the 3300 XL 25 mm Proximitor Sensor for a 9.0 m (29.5 ft) system with panel mounting. It is built to condition the signal from the very large 25 mm probe used for differential expansion measurement on mid-size to large steam turbine generators, where a linear range of 12.7 mm is required.

In the 330850-AA-BB pattern, 90 selects 9.0 m system length with panel mount and 00 means no agency approvals.

330850-90-00 technical specifications

What the 330850-90-00 does in a differential expansion channel

The 25 mm Proximitor Sensor drives a large-coil probe with a radio-frequency signal and converts the loading from the target into a negative dc voltage. The sensitivity is deliberately low, 0.787 V/mm (20 mV/mil), in return for a linear range of 12.7 mm (500 mils). That range is what lets two probes follow a rotor collar or ramp as the turbine rotor grows axially relative to its casing, which is the differential expansion (DE) measurement the datasheet names as the system’s main application.

330850-90-00: 9.0 m reach for large turbines

A 9.0 m system is chosen when the sensor must sit in a cabinet or terminal box away from the turbine casing, with the probe mounted near the collar. Probe plus extension cable must equal 9.0 m: a 1.0 m probe with an 8.0 m 330854 extension (code 080), or a 9.0 m probe on its own. Five-metre probes are designed for 5.0 m sensors only.

The extension cables for the 25 mm line are high-temperature FluidLoc types (codes 24 and 25 for armored), reflecting the harsh turbine environment. The probe itself keeps its accuracy continuously up to 200 °C, with intermittent excursions to 250 °C for less than 24 hours.

Related parts and family overview for 330850-90-00

Siblings are 330850-50-00 (5.0 m panel) and the DIN versions 330850-51-00 and 330850-91-00. The probe family is 330851, extension is 330854 and the optional sliding bracket is 330853 with the 163854 dial indicator verification kit. The ordering table for 330850-AA-BB offers four length and mounting codes (50, 51, 90, 91) and two approval codes (00 and 05). The 25 mm line is only offered as 5.0 m and 9.0 m systems, so there is no 1.0 m sensor option as there is on the 8 mm line.

Selection and ordering checklist for 330850-90-00

• Confirm the application is differential expansion or another long-range measurement
• Confirm total system length of 9.0 m (1.0 m probe plus 8.0 m extension, or a 9.0 m probe)
• Confirm panel mount rather than DIN
• Select probe case: 1 1/4-12, M30x2, 1 1/2-12, M39x1.5 or smooth case
• Check whether a sliding bracket is needed for verification
• Confirm the target is at least 61 mm (2.4 in) diameter

Installation, commissioning and maintenance of the 330850-90-00

Mount the sensor on its four-hole panel base, wire the supply, common and signal to the SpringLoc strip and connect the extension cable. The datasheet requires verifying the transducer by physically moving it to simulate shaft collar motion, which is why the optional sliding bracket is offered.

Operation at more positive than -23.5 Vdc can reduce linear range, so measure the supply at the sensor terminals and keep within -17.5 to -26 Vdc. Use barriers only when needed, and then supply at -23 to -26 Vdc.

• Keep the gap and range check as part of every outage routine
• The probe case thread should match the turbine casing adapter
• Protect connectors with the supplied connector protectors and the installation tool
• Frequency response is 0 to 2.7 kHz, suitable for slow expansion signals
• Bend radius is 25.4 mm (1.0 in)

Typical applications in Oman and the GCC

For the 330850-90-00 the typical Oman and GCC use is steam turbine generators in power and desalination plants, where differential expansion must be watched during start-up and shutdown. The long linear range tolerates the large axial growth of big rotors, and the 9 m system lets the sensor stay in a cooler terminal box away from casing heat. The same sensor family also suits long-range position measurements where an 8 mm probe would run out of range.

Information to send with an RFQ for 330850-90-00

• Part number 330850-90-00 and quantity
• Probe model (330851 options) and extension cable (330854) lengths
• Turbine type and measurement arrangement (single or complementary input)
• Whether a sliding bracket and dial indicator kit are needed
• Delivery location in Oman or the GCC and required date

Related Bently Nevada products: Bently Nevada 3300 XL 25 mm Proximitor Sensor 330850-51-CN, Bently Nevada 330105-02-12-10-02-05 3300 XL Probe, Bently Nevada 125680-01 3500/40M Proximitor I/O Module, Bently Nevada 3300 XL 8mm Proximity Transducer System, Bently Nevada 3300 XL Proximitor 330180-51-CN and Bently Nevada 3500/42M Proximitor Seismic Monitor.

Documents and quotation

The manufacturer datasheet for the 330850-90-00 is attached on this page under Documents, so wiring, ordering options and environmental limits can be checked before you order.

The datasheet includes the dimension drawings for the 330850 panel- and DIN-mount sensors. Seven Star LLC is an independent supplier based in Muscat; submit the part number, quantity and delivery location and we reply with availability and a quotation.