EPRO PR9268/300-000 Seismic Velocity Sensor

The EPRO PR9268/300-000 is a high-performance seismic velocity sensor designed for absolute vibration measurement on bearing housings and machine casings. It is part of the PR9268 series of sensors widely used in turbomachinery protection systems. The sensor operates on the electrodynamic principle, generating an output voltage proportional to the velocity of vibration. With a sensitivity of 20 mV/mm/s and a wide frequency range from 1 Hz to 10 kHz, it is ideal for detecting low-frequency vibrations as well as higher-frequency components associated with gear mesh and blade pass. Its rugged, hermetically sealed construction ensures reliable operation in harsh industrial environments.

Key Features

• High Sensitivity: 20 mV/mm/s (±5%) provides excellent signal-to-noise ratio for early fault detection.

• Wide Frequency Range: 1 Hz to 10 kHz covers most machinery vibration frequencies, including slow-speed rotors.

• Self-Generating Principle: No external power required for signal generation; passive design simplifies installation.

• Rugged Construction: Stainless steel housing, hermetically sealed, IP67 protection against dust and water.

• Integral Cable: Available with various cable lengths and connectors (model /300-000 indicates specific cable/connector options).

• API 670 Compliant: Designed to meet the stringent requirements of API 670 for machinery protection sensors.

Technical Specifications

• Transducer Type: Electrodynamic velocity sensor (seismic)

• Sensitivity: 20 mV/mm/s ±5% at 80 Hz

• Frequency Range: 1 Hz to 10 kHz (±3 dB)

• Dynamic Range: Up to 1000 mm/s peak

• Transverse Sensitivity: ≤5%

• Operating Temperature: -40°C to +120°C

• Protection Class: IP67 (with mating connector)

• Mounting: Single M8 stud or threaded hole

• Connector: Integral cable with MS-type or BNC (depending on suffix)

• Certifications: CE, ATEX / IECEx optional (hazardous area versions available)

Applications

The PR9268/300-000 is used to measure absolute vibration on bearing housings of turbines, compressors, pumps, fans, and generators. It provides critical data for monitoring machine condition, detecting unbalance, misalignment, bearing faults, and structural resonances. It is commonly installed on gas and steam turbines, centrifugal compressors, and large electric motors in power plants, refineries, and offshore platforms.

Integration and Calibration

The sensor connects directly to compatible monitors such as EPRO MMS3120 or MMS6000 series, which provide signal conditioning and alarm functions. It requires no external power; the monitor supplies a constant current source for impedance matching. Calibration is typically performed by the manufacturer; field calibration is not required. The sensor's output can be integrated to displacement or differentiated to acceleration using the monitor's electronic modules.

Reliability and Environmental Compliance

Built to withstand the rigors of continuous industrial service, the PR9268 is tested for shock (100 g) and vibration (20 g). Its stainless steel body and hermetic seal resist corrosion and ingress. The sensor is CE marked and available with hazardous area approvals for use in explosive atmospheres.

With its proven reliability and accuracy, the EPRO PR9268/300-000 seismic velocity sensor is a trusted choice for protecting critical rotating machinery worldwide.