Bently Nevada 3300/50-01 / -02 / -03 Tachometer Monitor, One Rack Position, 2.5 W Nominal

Brand Bently Nevada

Model Bently 3300/50-01 / -02 / -03

Product Overview

The Bently Nevada 3300/50 is a single-channel tachometer monitor module for the Bently Nevada 3300 Series machinery protection system, designed to continuously measure shaft rotative speed, rotor acceleration or zero-speed condition on critical rotating equipment. It occupies one position in the 3300 rack — any slot except positions 1 and 2, which are reserved for the power supply and system monitor — and is powered directly from the rack backplane at a nominal 2.5 W. The 3300 platform itself is built to satisfy API 670 requirements for continuous online machinery protection, and the Bently Nevada 3300/50 is the dedicated speed-measurement element within that architecture.

Three functional variants share the same hardware: the Bently Nevada 3300/50 configured as -01 is a Dual Setpoint Tachometer, -02 is a Zero Speed Tachometer, and -03 is a Rotor Acceleration Tachometer, with further order options covering sealed alert relays, agency approval and internal or external safety barriers. Although it is a single-channel monitor, the Bently Nevada 3300/50 accepts inputs from two transducers and applies internal voting logic between them, so a single transducer failure cannot produce a false speed indication. Compatible inputs include 3300, 7200 and 3000 Series Proximitor probes as well as magnetic pickups, across a frequency range from DC to 10 kHz.

For the plant, the value of the Bently Nevada 3300/50 is that it produces a trustworthy speed number and a set of alarm contacts in dedicated hardware, independent of PLC scan time, and delivers that information onward as a proportional recorder output, front-panel LCD readout and buffered transducer signal for portable diagnostic instruments.

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Description

Technical Specifications

Parameter Name	Parameter Value
Product Model	Bently Nevada 3300/50 (order format 3300/50-AXX-BXX-CXX-DXX)
Manufacturer	Bently Nevada (GE / Baker Hughes Bently Nevada)
Product Type	Tachometer monitor module, single channel
Series / Platform	Bently Nevada 3300 Series Machinery Protection System, API 670
Functional Variants	-01 Dual Setpoint Tachometer; -02 Zero Speed Tachometer; -03 Rotor Acceleration Tachometer
Monitoring Channels	One; accepts two transducer inputs with internal voting logic
Compatible Transducers	3300, 7200 and 3000 Series Proximitor probes; magnetic pickups
Input Frequency Range	DC to 10 kHz (auto threshold 10 Hz to 10 kHz)
Input Signal Level	0.5 to 50 V peak-to-peak
Manual Threshold Range	User-selectable 0 to -18 Vdc
Hysteresis Range	User-selectable 0.2 to 2.0 V
Events per Revolution	Numerator 1 to 255; denominator 1 to 255 (ratio ≥ 0.1)
Shaft Speed Range	1 to 99,999 RPM
Rotor Acceleration Range	-9,999 to +9,999 RPM/min
Zero Speed Threshold	Typically below 100 RPM
Speed Display Accuracy	Within ±1 RPM at +25 °C; display resolution ±1 RPM
Recorder Output	User-programmable +4 to +20 mA, 0 to -10 Vdc, or +1 to +5 Vdc
Output Compliance	100 Ω voltage output impedance; 0 to +12 Vdc compliance across 0-600 Ω at 4-20 mA
Buffered Transducer Output	One coaxial BNC per transducer on the front panel, short-circuit protected, 100 Ω
Transducer Supply Voltage	-24 Vdc or -18 Vdc, user-programmable in the power supply
Alarm Setpoints	Digitally adjustable 0 to 100% full scale, stored in nonvolatile memory
Alert Relay Options	None, epoxy-sealed, or hermetically sealed
Full Scale Range Options	100, 200, 500, 1000, 2000, 5000, 10000, 20000, 50000, 99999 RPM (shipped at 5000 RPM)
Front Panel Display	LCD, approx. 84 x 38 mm, speed and indication LEDs for OK, Alert, Danger, Bypass
Power Consumption	2.5 W nominal from 3300 rack backplane
Operating Temperature	0 °C to +65 °C; storage -40 °C to +85 °C
Relative Humidity	Up to 95% non-condensing
Dimensions (H x W x D)	241.3 x 24.4 x 241.9 mm
Weight	Approx. 0.82 to 1.0 kg
Rack Position	One slot, any position except 1 and 2

Main Features and Advantages

Two transducers, one channel, fewer false indications: The Bently Nevada 3300/50 accepts two independent transducer inputs and resolves them with internal voting logic. On machines where a speed signal drives an alarm, a single failed probe or a severed cable would otherwise create a false low-speed or zero-speed condition and a spurious trip; voting removes that failure mode without doubling the number of monitors in the rack. Mixed input types are supported, so a proximity probe reading a keyphasor notch can be paired with a magnetic pickup for verification.

Measurement configured to the machine rather than to the module: With selectable full-scale ranges from 100 to 99,999 RPM, programmable events per revolution, a user-selectable threshold from 0 to -18 Vdc and adjustable hysteresis from 0.2 to 2.0 V, the Bently Nevada 3300/50 can be matched to a slow-turning gear or a high-speed turbine shaft rather than forcing the machine into a fixed instrument range. That configurability is what allows one part number to serve an entire plant’s speed-measurement needs, which directly reduces spare-parts variety.

Outputs that fit any control architecture: A user-programmable recorder output — +4 to +20 mA, 0 to -10 Vdc or +1 to +5 Vdc — feeds DCS, PLC and historian inputs for trending, while the front-panel BNC buffered outputs give vibration analysts a clean, short-circuit-protected copy of the raw transducer signal without breaking the loop. Alarm setpoints are digitally adjustable across 0 to 100% of full scale and held in nonvolatile memory, so configuration survives a power cycle.

Important application boundary: Bently Nevada states explicitly in the 3300/50 operation manual that its tachometers are not designed for use independently as, or as a component of, a speed control or overspeed protection system, because they do not provide the protective redundancy and response speed those functions require. The Bently Nevada 3300/50 is a monitoring and annunciation device; where a protective trip is required, a dedicated overspeed protection system such as the 3300/53 must be used.