Product Core Brief

• Model: PR9268/303-000
• Brand: Emerson (EPRO / Machinery Health)
• Series: Series
• Core Function: Measures absolute mechanical vibration of rotating machinery casings and converts it into a proportional velocity voltage signal.
• Product Type: Absolute Vibration Transducer (Seismic Velocity Sensor)
• Key Specs: 4-1000 Hz Frequency Range | 3000 µm Peak-to-Peak Amplitude | IP55/IP65 Protection | Single Measurement Direction
• Condition: New Original / New Surplus

EMERSON PR9268/303-000

Product Introduction

The EMERSON /303-000 is a high-performance absolute vibration transducer designed for the continuous monitoring of critical rotating machinery. As part of the EPRO Machinery Health product line, this sensor is engineered to measure absolute mechanical vibration and provide a voltage signal directly proportional to the vibration velocity.

Operating on an electrodynamic principle, the sensor consists of a seismic mass and a measuring coil supported by a spring within a permanent magnetic field. As the sensor casing vibrates with the machine, the relative movement generates the output signal. With a broad frequency response of 4 Hz to 1000 Hz and the ability to measure peak-to-peak amplitudes up to 3000 µm, the /303-000 is ideal for monitoring turbines, compressors, fans, and pumps. It integrates seamlessly with EPRO MMS 3000 and MMS 6000 Turbine Supervisory Instrumentation (TSI) systems, providing reliable data for API 670 compliant machinery protection.

Key Technical Specifications

• Module Type: Absolute Vibration Transducer
• System Compatibility: EPRO MMS 3000, MMS 6000 TSI Systems
• Measurement Principle: Electrodynamic (Velocity)
• Frequency Range: 4 Hz to 1000 Hz
• Amplitude Limit: Up to 3000 µm (Peak-to-Peak)
• Sensitivity: 28.5 mV/mm/s (at 50 Hz, 20°C, 100 kΩ load)
• Measurement Direction: Single Direction (Vertical or Horizontal only)
• Protection Rating: IP55 / IP65
• Explosion Protection: EEx ib II B / II C (Zone 1 compatible with safety barrier)
• Operating Temperature: Up to 200°C (depending on specific sub-variant)

Quality Control Process (Engineer’s Perspective)

1. Incoming Verification: Verify part number . Inspect the external casing for physical damage and check the electrical connector pins for corrosion or bending.
2. Visual Inspection: Ensure the mounting threads are intact and the IP-rated sealing surfaces are free from scratches or debris.
3. Electrical Test: Measure the coil resistance and verify it falls within the manufacturer’s specified tolerance. Check insulation resistance to ground.
4. Functional Test: Perform a shaker table calibration test to verify sensitivity (mV/mm/s) and phase response across the 4-1000 Hz frequency band.
5. Final QC & Packaging: Seal in an anti-static bag. Apply a QC Passed label with the date.

EMERSON PR9268/303-000

Replacement Pitfall Guide

❗ Measurement Direction: The series sensors are designed for a single measurement direction (either vertical or horizontal). Verify the exact orientation required for your machine casing before installation. Do not confuse this with the PR9266 series, which features a lifting coil for dual-direction measurement.

❗ Sensor vs. Proximity Probe: This is an absolute casing vibration sensor. Do not confuse it with EPRO eddy current proximity probes (e.g., PR6423 series), which measure relative shaft vibration. They require completely different signal conditioning modules.

❗ System Compatibility: This sensor is designed to connect directly to EPRO MMS 3000 or MMS 6000 measurement amplifiers. Ensure your TSI system’s input module is configured for the correct sensitivity and frequency range of the /303-000.

❗ Mounting Torque: Proper mechanical coupling to the machine casing is critical for accurate low-frequency (4 Hz) response. Always use the specified mounting stud and torque to the manufacturer’s exact specification to prevent signal attenuation.

❗ Cable & Grounding: Use the specified low-capacitance extension cable. Ensure the sensor housing is properly grounded through the mounting stud to prevent electrical noise from corrupting the low-level velocity signal.

Keep these in mind and you’ll cut 90% of rework time.

Compatibility Matrix & Benchmarks

• → MMS 6000 / MMS 3000 : Required — EPRO TSI measurement amplifier/chassis for signal conditioning.
• → PR9266 Series : Alternative — Use PR9266 if dual-direction (vertical/horizontal) measurement is required from a single sensor.
• → PR6423 Series : Complementary — Pair with eddy current probes for comprehensive relative shaft + absolute casing vibration monitoring.
• → Safety Barriers : Required — Mandatory for operation in Zone 1 hazardous areas (EEx ib II B/C).

Benchmarks:

• Low-Frequency Response: Reliable measurement down to 4 Hz for slow-speed machinery
• Signal Integrity: High-output, low-impedance coil design provides excellent anti-interference capability

Need me to pull up the matching EPRO MMS 6000 Measurement Amplifier or the PR6423 Relative Shaft Vibration Probe to complete your TSI monitoring setup? Let me know which one you’d like.