Bently Nevada 3300/25 Dual Accelerometer Monitor

Product Overview

The 3300/25 monitors vibration levels from two independent accelerometers simultaneously for machinery protection. This dual-channel monitor provides continuous surveillance of rotating equipment such as turbines and compressors. Plant operators rely on this monitor for early detection of mechanical degradation and impending failures. The 3300/25 integrates seamlessly with Bently Nevada 3300 monitoring systems for comprehensive vibration management.

Key Specifications

Parameter	Specification
Model	3300/25
Number of Channels	2 (dual independent)
Sensor Type	Accelerometer (piezoelectric)
Input Signal Range	0–10 V AC (from accelerometer)
Frequency Range	2 Hz – 10 kHz
Output Signal	4–20 mA (proportional to vibration)
Alarm Setpoints	2 per channel (Alert and Danger)
Relay Outputs	4 SPDT (2 per channel)
Power Supply	24 V DC nominal (20–30 V DC range)
Current Consumption	120 mA (typical)
Isolation	500 V AC (input to output)
Response Time	< 100 ms (to alarm)
Operating Temperature	-20°C to +65°C
Storage Temperature	-40°C to +85°C
Humidity Range	5% to 95% RH (non-condensing)
Dimensions	241 mm × 102 mm × 38 mm
Weight	1.2 kg
Mounting Type	Panel mount or DIN rail
Indicator LEDs	Power, Channel OK, Alert, Danger
Diagnostic Features	Sensor fault detection, open-circuit check

Dual-Channel Vibration Monitoring

The 3300/25 accepts inputs from two accelerometers for comprehensive vibration surveillance. Each channel operates independently with its own setpoint configuration and alarm logic. This monitor covers a frequency range from 2 Hz to 10 kHz for broad vibration detection. The dual-channel design allows monitoring of two separate machine locations simultaneously. Consequently, operators gain complete visibility into equipment mechanical health.

Signal Processing and Output Capabilities

The 3300/25 processes accelerometer signals and generates proportional 4–20 mA outputs for each channel. These outputs interface directly with distributed control systems and PLC platforms. The monitor provides two alarm setpoints per channel: Alert and Danger. Each channel also offers two SPDT relay outputs for external alarm annunciation. The monitor’s response time remains under 100 ms for rapid fault detection and response.

Alarm Configuration and Annunciation

The 3300/25 features fully adjustable Alert and Danger setpoints for each independent channel. Operators can configure these setpoints through the front-panel controls or remote interface. Each channel provides two SPDT relay contacts for alarm status indication. These relays activate when vibration levels exceed configured thresholds. Furthermore, the monitor includes a bypass function for maintenance operations.

Power and Electrical Isolation

This vibration monitor draws 120 mA from a 24 V DC supply with 20–30 V DC tolerance. The 3300/25 provides 500 V AC isolation between input circuits and output channels. This electrical separation prevents ground loops and protects connected equipment effectively. The monitor’s power supply design minimizes heat generation within the enclosure. Consequently, the device maintains reliable operation without active cooling requirements.

Mechanical Construction and Installation

The 3300/25 comes in a durable panel-mount housing measuring 241 mm × 102 mm × 38 mm. The monitor weighs 1.2 kg and suits standard 19-inch rack or panel installations. Users can also mount the device on DIN rails using the optional adapter kit. Front-panel LEDs provide clear visual indicators for power, channel status, and alarms. The compact form factor saves valuable space in equipment cabinets.

Sensor Compatibility and Diagnostics

The 3300/25 accepts standard piezoelectric accelerometers with 0–10 V AC output. Built-in sensor fault detection identifies open circuits or shorted sensor cables promptly. Diagnostic indicators alert operators when sensor integrity becomes compromised. The monitor also performs continuous self-check routines for internal circuit verification. This diagnostic capability enhances overall system reliability and reduces troubleshooting time.

Application Suitability

The 3300/25 suits vibration monitoring for pumps, motors, fans, and compressors. This monitor excels in applications requiring continuous surveillance of critical rotating machinery. Its dual-channel design enables monitoring of both bearing housings and machine casings. The device handles vibrations in chemical, petrochemical, and power generation plants. Furthermore, the 3300/25 integrates with Bently Nevada System 1 for advanced condition monitoring.

Installation and Configuration Guidance

Mount the 3300/25 securely in a panel or rack using the supplied mounting hardware. Connect the accelerometer cables to the appropriate input terminals for each channel. Wire the 4–20 mA outputs to the DCS or PLC analog inputs accordingly. Set the Alert and Danger thresholds using the front-panel potentiometers. Test alarm functionality after configuration to ensure correct relay operation. Perform periodic sensor checks to verify measurement integrity and cable condition.