Bentley 3300/50-01-02-00-00 Speed Monitoring Module - Detailed Product Description

I. Product Overview

The Bentley 3300/50-01-02-00-00 is a precise speed monitoring module of the TSI (Turbo Generator Monitoring Instrument) in the 3300 series of the Nevada branch of Baker Hughes (formerly GE). It is a single-channel speed monitoring unit, mainly used for continuous online monitoring of the rotational speed and zero speed of rotating machinery. It also supports basic speed and acceleration monitoring capabilities. This module is compatible with the original electric eddy current probe and magnetic-electric speed sensor of Bentley. It has dual sensor redundant input and hardware voting logic, which can avoid monitoring interruption or false alarms caused by a single sensor failure. It is widely used in key equipment such as steam turbines, gas turbines, centrifugal compressors, large fans, pumps, and drive motors in industries such as power, petrochemical, metallurgy, and water treatment, for monitoring and warning of overspeed, underspeed, and zero speed states. It cannot be used independently as an overspeed protection system. The module adopts a 19-inch standard rack design, supports hot swapping, and can be mixed with other functional modules of the 3300 series. It is compatible with the 3300 series rack, power supply, and bus system to ensure the long-term stable operation of the unit.

II. Model Coding Rules (3300/50-XX-XX-XX-XX)

3300: Bentley 3300 series modular TSI system, 19-inch standard rack, centralized power supply, supports hot swapping and multi-module mixed installation architecture.

50: Function code, speed monitoring module (Tachometer), mainly for continuous online monitoring of the rotational speed and zero speed of the shaft, also includes basic acceleration monitoring.

The 1st position (Monitoring Type): 01 = Standard speed monitoring, with speed measurement as the core, supports zero speed detection, has basic acceleration response capability.

The 2nd position (Relay Type): 02 = Dual relays (Warning + Danger), equipped with two epoxy resin sealed relays, corresponding to ALERT (Warning) and DANGER (Danger) alarm outputs, with high protection level.

The 3rd position (Certification Option): 00 = No special certification, standard type without additional explosion-proof or safety certification.

The 4th position (Safety Barrier Option): 00 = No safety barrier, non-explosion-proof design, only applicable to non-flammable and non-explosive hazardous areas.

III. Core Functions

Dual sensor redundant input and hardware voting

Single-channel monitoring unit, supports connection of two speed sensors (electric eddy current probe, magnetic-electric speed sensor), with built-in hardware voting logic. When one sensor has a break, short circuit, or abnormal signal, it automatically switches to the normal signal circuit, effectively avoiding monitoring interruption or false alarms caused by a single sensor failure, significantly improving the monitoring reliability in complex working conditions.

High-precision speed and zero speed monitoring

Accurately measure the real-time rotational speed of the rotating shaft (RPM), with a programmable range (0–50000 RPM), and also have an independent zero speed judgment function. The zero speed threshold (0–5 RPM) can be programmed, used for confirming the unit shutdown state, control of the cranking device， preventing incorrect startup or equipment reversal， suitable for all working conditions of unit start-stop， speed increase， and speed reduction.

Two-level alarm output (Warning + Danger)

Equipped with two epoxy resin sealed SPDT relays (ALERT Warning， DANGER Danger)， with rated load of 250V AC/3A， 30V DC/3A， moisture-proof， dust-proof， and resistant to environmental interference. The speed warning and danger threshold are independently set， with alarm delay of 0–10 seconds programmable， filtering instantaneous fluctuations， output to audible and visual alarms， DCS/PLC or interlock circuits， achieving hierarchical warning and protection.

Basic rotor acceleration response  basic rotor acceleration (RPM/s) monitoring capability, capable of capturing sudden changes in speed, abnormal acceleration, etc. The response time is ≤ 150ms. It assists in identifying abnormal fluctuations during the unit's speed-up process， providing data support for early fault warning.

Panel display and local configuration

The front panel integrates analog display heads and digital display windows, displaying the speed value in real time; it is equipped with OK, ALERT, DANGER, and BYPASS LED indicators, visually presenting the module's operation, alarm, and bypass status. It is paired with simple operation buttons, supporting on-site setting of speed range, alarm threshold, delay, zero speed value, etc., without the need for an upper computer to complete the basic configuration.

Isolated buffered signal output

The rear terminals provide two isolated buffered outputs， which can synchronously transmit the original speed/acceleration signals to the recorder， oscilloscope， or external monitoring system for data recording， secondary analysis， and fault tracing. The signal isolation strength is high， and the anti-interference ability is strong.

Comprehensive self-diagnosis and fault identification

24-hour real-time monitoring of sensor failures， signal over-limitations， power supply abnormalities， and module hardware faults. It can clearly distinguish real speed abnormalities from sensor/loop faults. The panel LED synchronously displays the fault type， facilitating rapid troubleshooting by maintenance personnel and reducing maintenance difficulty.

Strong anti-interference and system integration

Metal shielding enclosure， input/output/power electrical isolation ≥ 2500V AC， strong anti-common-mode interference ability， suitable for complex electromagnetic environments such as frequency converters and high-voltage equipment. Compatible with 3300 series system bus， can be connected to System 1 status monitoring software to achieve remote configuration， data storage， trend analysis， and remote access.

IV. Technical parameters

Measurement parameters

Monitoring channel： single channel (dual sensor redundant input voting).

Compatible sensors： original Bently electromagnetic flowmeter， magnetic-electric speed sensor.

Speed range： 0–50000 RPM (programmable range).

Acceleration monitoring： basic rotor acceleration (RPM/s)， response time ≤ 150ms.

Zero speed threshold： 0–5 RPM (programmable).

Measurement accuracy： ≤ ±0.1% full scale， resolution 0.1 RPM.

Alarm settings： two-level alarm (ALERT warning， DANGER danger)， threshold independently set， delay 0–10s adjustable.

Electrical parameters

Power supply： -24V DC (±10%)， unified power supply on the back panel of the frame.

Power consumption： ≤ 3W， typical 1.5W.

Sensor input： two pulse signals， input impedance matches the standard parameters of Bently speed sensors.

Relay output： 2 SPDT non-polarized contacts (epoxy resin sealed)， 250V AC/3A， 30V DC/3A.

Buffer output： two isolated analog signals (speed/acceleration)， suitable for external equipment connection.

Isolation performance： input/output/power isolation ≥ 2500V AC.

Environmental and mechanical parameters

Operating temperature： -30℃ ~ +65℃ (standard type).

Storage temperature： -40℃ ~ +85℃.

Relative humidity： 0%–95% (no condensation).

Installation method： 19-inch standard frame slot installation， supports hot swapping.

Size： 254mm × 165mm × 63.5mm.

Weight： approximately 1.2kg.

Protection level： IP20 (installed in the control cabinet).

Certification and compliance

Industry standards： comply with API 670 rotating machinery monitoring protection standards.

Electromagnetic compatibility： CE certification， compliant with EN 61000-6-2/4 specifications.

Safety and environmental protection： UL safety certification， RoHS environmental compliance.

Explosion-proof rating: Non-explosion-proof design, without safety barrier, only applicable to non-hazardous areas.

V. Structural Design

The module adopts an integrated compact frame structure, divided into the front panel, the internal main control circuit, and the rear wiring terminals. The front panel integrates analog display heads, digital display windows, and multiple groups of LED status indicator lights, along with local operation buttons. It enables real-time viewing of rotational speed, alarms, and module status, as well as parameter configuration, making the operation intuitive and convenient. The internal circuitry includes dual-channel signal conditioning units, hardware voting logic circuits, rotational speed/acceleration calculation units, dual-level alarm comparison circuits, and dual-relay drive circuits. The functional divisions are clear, the layout is reasonable, effectively avoiding signal interference, and ensuring long-term stable operation. The wiring terminals at the rear are clearly divided and marked, covering two channels of sensor input, dual-relay output, buffered signal output, and power/communication interfaces, facilitating on-site wiring, maintenance, and repair. The module and the frame are connected using gold-plated connectors, with reliable contact, wear-resistant, and oxidation-resistant properties, ensuring stable electrical connection during hot swapping, allowing for module replacement without stopping production, and reducing the impact of maintenance on production.

VI. System Compatibility

Hardware Compatibility

Frame and Power Supply: Compatible with 3300 series 19-inch standard frames, power modules, and system monitoring modules. Can be installed with vibration, shaft displacement, temperature, etc. modules.

Sensors: Fully compatible with original Bently electromagnetic flow velocity probes and magneto-electric speed sensors. The same specifications can be directly interchanged.

Output Connection: Dual-relay contacts can be connected to audible and visual alarms, DCS/PLC, interlock circuits; isolated buffered outputs can be connected to recorders, oscilloscopes, external monitoring instruments.

Software Compatibility

Configuration Software: Compatible with 3300 series dedicated configuration software, supporting remote parameter configuration, alarm logic editing, firmware upgrade.

Monitoring Software: Can be connected to System 1 equipment status monitoring software, enabling real-time data, trend analysis, fault recording, report generation, and remote access.

VII. Typical Application Scenarios

Power Industry: Rotational speed monitoring for thermal power / gas turbines, generators, induced draft fans, supply fans, etc., abnormal warning during start-up and shutdown with speed increase/ decrease anomalies, dual-level alarms to ensure safe start-up and stable operation of the unit.

Petrochemical Industry: Rotational speed monitoring for non-explosion-proof centrifugal compressors, process turbines, large-scale process pumps in non-hazardous areas, over-speed/under-speed classification warning, rotational speed sudden change, acceleration anomaly identification, preventing equipment failure from causing production interruptions.

Metallurgical Industry: Rotational speed status monitoring for blast furnaces, sintering system fans, large-scale transmission motors, etc., abnormal warning during start-up and shutdown, dual-level alarm linkage interlock, reducing the risk of equipment failure shutdown.

General Industry: Grinding mills, fans, water treatment, etc. in cement, papermaking, water treatment industries, online rotational speed monitoring, zero rotational speed interlock protection, classification warning, extending equipment service life, reducing operation and maintenance costs.

VIII. Installation and Maintenance Specifications

Installation Requirements

Frame Installation: Push the frame smoothly into the vacant slot of the 3300 frame, ensure that the rear connectors are fully engaged, tighten the panel screws, and prevent loosening.

Sensor Wiring: Connect the two channels of rotational speed sensor cables according to the channel markings, single-ended grounding the shield layer, suppressing electromagnetic interference.

Alarm Wiring: Distinguish between ALERT and DANGER relay contacts, connect to the alarm/interlock circuits to ensure correct logic.

Power-on Configuration: Confirm normal -24V DC power supply, then set the rotational speed range, dual-level alarm thresholds, zero rotational speed value, alarm delay, and save through the panel or software.

Sensor Installation: Fix the probe at the shaft end or the speed measurement gear disc position, strictly control the installation gap, fix firmly, protect the cable, and avoid vibration wear. Inspection: Regularly observe the display of the panel and the LED status to confirm that the rotational speed data is normal and there are no fault alarms; check that the terminals are not loose, oxidized, or overheated.

Calibration: Every year, calibrate the accuracy using a standard rotational speed generator, in accordance with API 670 standards.

Cleaning: Regularly clean the dust on the module and the rack to ensure ventilation and heat dissipation, and to avoid short circuits and poor heat dissipation caused by dust accumulation.

Replacement of spare parts: When the module, sensor, or cable is damaged, it is necessary to select original Bentley components of the same model to ensure compatibility and measurement accuracy.

IX. Usage Precautions

This module is not explosion-proof. Installation and use are strictly prohibited in flammable and explosive hazardous areas.

It cannot be used independently as the main overspeed protection device. It is only used for condition monitoring and level warning; the overspeed protection of key units requires a dedicated triple-redundant overspeed protection system.

It must be paired with the original Bentley speed sensor. Different specifications of sensors cannot be mixed, otherwise the signals will not match and the measurement will fail.

The installation gap of the sensor must be strictly set according to the manual. Abnormal gap will cause signal distortion and increased measurement error.

It is prohibited to disassemble the module, modify the internal circuitry, or modify the sensor calibration parameters without authorization. Illegal operations will cause equipment damage and invalid warranty.

Before wiring, maintenance, or replacing the module, the power supply of the rack must be cut off to prevent short circuits and electric shock accidents.

The double alarm threshold and delay must be set in combination with the unit's process. Improper parameters will lead to frequent false alarms or warning failure.

The installation location should be far away from power frequency converters, transformers, high-voltage cabinets, etc., which are strong electromagnetic interference sources, to reduce signal interference and ensure stable monitoring.