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

I. Product Overview

The Bentley 3300/50-01-01-01-02 is a single-channel precision speed monitoring module within the TSI (Turbo Generator Monitoring Instrument) system of the Bentley Nevada 3300 series under Baker Hughes. It is specifically designed for continuous online monitoring of the rotational speed and zero speed of rotating machinery. It also has the basic ability to monitor speed and acceleration. This module is compatible with the original Bentley electrically-driven velocity probe and magnetic-electric speed sensor. It integrates dual sensor redundant input and hardware voting logic, effectively avoiding monitoring interruptions or false alarms caused by a single sensor failure. It is widely used in steam turbines, gas turbines, centrifugal compressors, large fans, pumps, and drive motors in key equipment in fields such as power, petrochemicals, metallurgy, and water treatment, for monitoring and warning of overspeed, underspeed, and zero speed states. It cannot be used independently as a main overspeed protection device. The module adopts a 19-inch standard rack design, supports hot swapping, and can be mixed with 3300 series vibration, shaft displacement, temperature, and other functional modules. It is compatible with 3300 series racks, power supply, and bus systems to ensure long-term stable operation of the unit.

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

3300: Bentley 3300 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 monitors the rotational speed and zero speed of the shaft, also includes basic acceleration monitoring.

The 1st position (Monitoring Type): 01 = Standard speed monitoring, centered on speed measurement, supports zero-speed detection, has basic acceleration response capability.

The 2nd position (Relay Type): 01 = Single relay (warning), equipped with a single epoxy resin sealed warning relay, moisture-proof, dust-proof, and resistant to environmental interference.

The 3rd position (Certification Option): 01 = With basic safety certification, compliant with general industrial safety standards, suitable for conventional industrial scenarios.

The 4th position (Safety Barrier Option): 02 = Built-in intrinsically safe safety barrier, explosion-proof design, can be directly used in flammable and explosive hazardous areas (such as petrochemical plant areas, gas stations, etc.).

III. Core Functions

Dual Sensor Redundant Input and Hardware Voting

Single-channel monitoring unit, supports connection of two speed sensors (electrical vortex 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 interruptions or false alarms caused by a single sensor failure, significantly improving the reliability of monitoring in complex working conditions.

High Precision Speed and Zero Speed Monitoring

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

Single-level Warning Output (with Safety Barrier)

Equipped with a single epoxy resin sealed SPDT warning relay， with rated load of 250V AC/3A， 30V DC/3A， moisture-proof， dust-proof， and resistant to environmental interference. The speed warning threshold， alarm delay (0–10 seconds) are independently set， filtering out instantaneous fluctuations， and output to audible and visual alarms， DCS/PLC or interlock circuits， achieving graded warning protection. Built-in intrinsically safe safety barrier， can be safely used in hazardous areas， isolating the dangerous side from the safe side circuit， preventing energy transmission and explosion risks.

Base rotor acceleration response

It has the capability to monitor the base rotor acceleration (RPM/s), capable of capturing situations such as sudden speed changes and abnormal acceleration. 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, and BYPASS LED indicators, visually presenting the module's operation, alarm, and bypass status. It is paired with simple operation buttons, allowing for on-site setting of parameters such as speed range, alarm threshold, delay, and zero speed value 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

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

Strong anti-interference and system integration

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

VII. Technical Parameters

Measurement parameters

Monitoring channel: Single channel (redundant input voting of dual sensors).

Sensor compatibility: Original Bently electromagnetic flow velocity probe, magnetic-electric speed sensor.

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

Acceleration monitoring: Base 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: Single-level warning (ALERT), threshold independently set, delay 0–10s adjustable.

Electrical parameters

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

Power consumption: ≤ 3W, typical 1.5W.

Sensor input: Two pulse signals, input impedance matched to Bently speed sensor standard parameters.

Relay output: 1 SPDT non-polarized contact (epoxy resin sealed), 250V AC/3A, 30V DC/3A.

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

Isolation performance: Input/output/power supply isolation ≥ 2500V AC; built-in intrinsically safe safety barrier, explosion-proof isolation level complies with Ex ia standard.

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 chassis slot installation, supports hot swapping.

Dimensions: 254mm × 165mm × 63.5mm.

Weight: Approximately 1.2kg.

Protection level: IP20 (installed in control cabinet).

Certification and compliance

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

Electromagnetic compatibility: CE certification, complies with EN 61000-6-2/4 specifications. Safety and Environmental Protection: UL safety certification, RoHS environmental compliance; Intrinsically safe explosion-proof certification (Ex ia IIC T4 Ga).

Explosion-proof Rating: Built-in safety barrier, can be directly used in flammable and explosive 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, with intuitive and convenient operation. The internal circuit includes dual-channel signal conditioning units, hardware voting logic circuits, rotational speed/acceleration calculation units, warning alarm comparison circuits, and relay drive circuits. The functional divisions are clear, the layout is reasonable, effectively avoiding signal interference, and ensuring long-term stable operation. An intrinsically safe safety barrier circuit is built-in to achieve electrical isolation between hazardous and safe areas. The wiring terminals at the rear are clearly divided and marked, covering two channels of sensor input, single-channel warning relay output, buffer signal output, and power/communication interfaces. The wiring terminals in the hazardous area are physically isolated from those in the safe area, 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, and eliminating the need to stop the machine for module replacement, 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: Single warning relay contacts can be connected to audible and visual alarms, DCS/PLC, interlock circuits; isolated buffer outputs can be connected to recorders, oscilloscopes, external monitoring instruments; the wiring terminals in the hazardous area are adapted to intrinsically safe sensors and equipment.

Software Compatibility

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

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

Petrochemical Industry: Explosion-proof centrifugal compressors, process turbines, large process pumps in hazardous areas, rotational speed monitoring, overspeed/underspeed warnings, identification of rotational speed changes and abnormal acceleration, preventing equipment failure from causing production interruptions, suitable for flammable and explosive working conditions.

Electric Power Industry: Thermal power / gas turbine, generator, induced draft fan, supply fan, rotational speed and zero-speed monitoring, abnormal warnings during start-up/shutdown speed increase/decrease, single-level warnings to ensure safe start-up/shutdown and stable operation of the unit, unit monitoring in hazardous areas is adapted.

Metallurgical Industry: High-temperature fan of blast furnace, sintering system fan, large transmission motor's rotational speed status monitoring, abnormal warnings during start-up/shutdown, warning linkage interlock, reducing equipment failure shutdown risks, suitable for hazardous areas in metallurgical plant.

General Industry: Cement, papermaking, water treatment, etc. industries' grinding mills, fans, water pumps, etc. high-speed rotating machinery, online rotational speed monitoring, zero-speed interlock protection, warning protection, extending equipment service life, reducing operation and maintenance costs, explosion-proof area adaptation.

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 to prevent loosening.

Sensor Wiring: In the hazardous area, connect the two rotational speed sensor cables according to the intrinsically safe specification, single-ended grounding of the shielding layer to suppress electromagnetic interference; wiring on the safe area side follows the conventional specification. Alarm wiring: Identify the warning relay contacts and connect them to the alarm/interlock circuit. Equipment in hazardous areas must meet the intrinsically safe explosion-proof requirements and ensure correct logic.

Power-up configuration: After confirming normal -24V DC power supply, set the speed range, warning threshold, zero speed value, alarm delay, and save the settings 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, secure it firmly, protect the cables well to avoid vibration wear; sensors in hazardous areas must comply with explosion-proof installation specifications.

Daily maintenance

Inspection: Regularly observe the panel display and LED status to confirm normal speed data and no fault alarms; check that the terminals are not loose, oxidized, or overheated, and ensure the sealing of the wiring in hazardous areas is intact.

Calibration: Calibrate the accuracy annually using a standard speed generator, in accordance with API 670 standards; the insulation performance of the safety barrier is regularly tested.

Cleaning: Regularly clean the dust on the module and the frame to ensure ventilation and heat dissipation, and avoid dust-induced short circuits or poor heat dissipation.

Replacement of spare parts: When the module, sensor, or cable is damaged, it must use the original Bentley model spare parts to ensure compatibility and measurement accuracy; hazardous area spare parts must have explosion-proof certification.

IX. Usage Notes

This module is equipped with an intrinsically safe safety barrier, which can be installed and used in flammable and explosive hazardous areas, but must strictly follow the explosion-proof installation specifications.

It cannot be used independently as the main overspeed protection device, and is only used for status monitoring and warning; the critical unit's overspeed protection 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. Sensors in hazardous areas must use intrinsically safe sensors; otherwise, the signals will not match and the measurement will fail.

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

It is prohibited to disassemble the module, modify the internal circuit, or modify the sensor calibration parameters privately. Illegal operations will cause equipment damage, invalid warranty, and explosion accidents; it is strictly forbidden to remove the safety barrier-related circuits.

Before wiring, maintenance, or replacing the module, the power supply of the frame must be cut off. Hazardous area operations must comply with explosion-proof safety regulations to prevent short circuits, electric shock, or explosion accidents.

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

The installation location should be far from strong electromagnetic interference sources such as frequency converters, transformers, and high-voltage cabinets to reduce signal interference and ensure stable monitoring.