Product Overview

• Brand: EPRO (now part of Emerson Automation Solutions)
• Model: PR9376-010-011
• Series: PR9376 (Eddy-Current Proximity Probe Series)
• Type: Non-Contact Eddy-Current Proximity Probe
• Industry: Power generation (steam/gas turbines, hydro generators), oil & gas (compressors, pumps), petrochemicals, and industrial manufacturing.
• Function: Performs non-contact measurement of rotor speed and keyphasor position for rotating machinery. It detects the presence of a metallic target (e.g., gear tooth, slotted disk, or keyway) on the rotating shaft using the eddy-current principle. The probe generates a high-frequency alternating current (AC) field; when the target passes through this field, it induces eddy currents in the target, causing a change in the probe’s impedance. This impedance change is converted into an electrical signal (AC voltage) and sent to a compatible signal conditioner (e.g., EPRO CON021, MMS6000 series modules). The signal is then processed to calculate shaft speed (via pulse frequency) and keyphasor position (to establish a reference point for vibration analysis), supporting machinery protection and condition monitoring.

Key Features

1. Dual-Purpose Measurement (Speed & Keyphasor)
   • Optimized for both speed monitoring (measuring shaft rotational frequency) and keyphasor positioning (providing a reference pulse for synchronizing vibration data with shaft angle). This dual functionality eliminates the need for separate sensors, reducing installation complexity and cost.
   • Compatible with common target designs: gear teeth (modular gears), slotted disks (with uniform slots), or single keyways (for keyphasor-only applications).
2. High-Speed Measurement Capability
   • Supports extremely high rotational speeds, with a maximum measurable frequency of up to 10 kHz (equivalent to 600,000 rpm for a 1-tooth target or 50,000 rpm for a 12-tooth gear). This makes it suitable for high-speed turbines and compressors in industrial applications.
   • Delivers stable, low-noise signals even at high speeds, ensuring accurate speed calculation and reliable keyphasor synchronization.
3. Robust Industrial Design
   • Built to withstand harsh operating conditions in power plants and oil & gas facilities:
     • Wide Temperature Range: Operates in -40°C to +120°C (standard) or up to +200°C (high-temperature variant, model-dependent), suitable for turbine enclosures and high-heat environments.
     • Vibration/Shock Resistance: Compliant with IEC 60068-2-6 (vibration, 5–500 Hz) and IEC 60068-2-27 (shock, 30g peak acceleration), durable for use near rotating machinery.
     • Ingress Protection: IP65-rated housing (dust-tight and protected against water jets), ensuring reliability in dusty or damp industrial settings.
4. Long-Term Stability & Compatibility
   • Low temperature drift (≤0.1% per 100K) and minimal long-term drift (≤0.2% per year), reducing the need for frequent calibration and ensuring consistent performance over time.
   • Fully compatible with EPRO’s signal conditioners and monitoring systems (e.g., MMS6000, CON021) and third-party industrial control systems (via standard analog/digital interfaces).

Key Specifications

1. Electrical Parameters
   • Operating Principle: Eddy-current (inductive) non-contact measurement.
   • Target Material: Ferromagnetic metals (e.g., steel 42CrMo4, cast iron) — non-ferromagnetic materials may require specialized calibration.
   • Sensing Distance (Nominal Air Gap): 1.0 mm (model-specific; “010” in the part number often indicates a 1.0 mm nominal gap, verify with EPRO).
   • Output Signal: AC voltage signal (amplitude-modulated, typically 1–10 Vpp), proportional to the target’s proximity to the probe tip.
   • Supply Voltage: Powered via a compatible signal conditioner (e.g., 24V DC from EPRO MMS6000 backplane); no direct external power required.
   • Cable Length: 3 meters (standard; “011” in the part number may indicate cable length, verify with EPRO); custom lengths (e.g., 5m, 10m) available upon request.
2. Performance Metrics
   • Maximum Measurable Frequency: 10 kHz (for speed measurement).
   • Resolution: 0.1 Hz (for frequency/speed calculation, dependent on signal conditioner).
   • Linearity: ±1% of full scale (over the nominal sensing distance range).
   • Temperature Drift: ≤0.1% of full scale per 100K (minimizes measurement error due to temperature fluctuations).
3. Physical & Environmental Attributes
   • Probe Tip Diameter: 8 mm (common for PR9376 series; model-dependent).
   • Housing Material: Stainless steel (316L) for corrosion resistance in harsh environments.
   • Operating Temperature: -40°C to +120°C (standard); up to +200°C (high-temperature option).
   • Storage Temperature: -50°C to +150°C.
   • Vibration Resistance: 10g (5–500 Hz, IEC 60068-2-6).
   • Shock Resistance: 30g (11 ms half-sine, IEC 60068-2-27).

Applications

• Turbine Speed Monitoring:
  • Primary application: Measures the rotational speed of steam/gas turbine shafts in power plants. Provides overspeed detection (e.g., 115% of rated speed) to trigger emergency shutdowns, protecting turbines from catastrophic damage.
  • Keyphasor reference: Establishes a fixed angular reference point for synchronizing vibration data (from EPRO MMS6210 modules) with shaft position, enabling order analysis and precise fault localization (e.g., rotor unbalance, misalignment).
• Compressor & Generator Protection:
  • Used in oil & gas compressors to monitor rotor speed and detect speed fluctuations that indicate load instability or mechanical faults (e.g., bearing wear).
  • In power plant generators, provides speed feedback for excitation control and synchronization with the electrical grid.
• Industrial Rotating Equipment:
  • Applied to pumps, fans, and gearboxes in petrochemical refineries and manufacturing plants. Monitors speed to ensure equipment operates within optimal ranges and detects slowdowns or overspeed conditions caused by process upsets or mechanical failures.

Availability and Support

• Condition: Available as new OEM (through Emerson Automation Solutions or authorized distributors) or genuine refurbished (via specialized industrial automation suppliers, e.g., AES Industrial, Hitech Control Systems).
• Warranty: 12-month warranty for new units (covers defects in materials/workmanship); refurbished units typically include a 6-month warranty.
• Documentation:
  • Technical datasheets, installation guides, and target design specifications are accessible to Emerson customers via Emerson’s Support Portal.
  • Emerson offers technical support for probe selection, installation alignment, and compatibility with EPRO monitoring systems.

Compatibility and Similar Products

• Compatible Systems & Components:
  • EPRO Signal Conditioners/Monitoring Modules: MMS6000 series (e.g., MMS6210 vibration module), CON021 communication module.
  • EPRO Signal Conditioners: PR9268 (dedicated eddy-current signal conditioner for PR9376 probes).
  • Third-Party Systems: Compatible with industrial DCS/SCADA systems (e.g., Siemens PCS 7, Emerson DeltaV) via signal conditioners with Modbus/PROFIBUS outputs.
• Similar EPRO/Emerson Models:
  • EPRO PR9376-020-011: PR9376 variant with a 2.0 mm nominal sensing gap (for larger target-probe clearances).
  • EPRO PR6423: Eddy-current probe focused on vibration/displacement measurement (complementary to PR9376 for comprehensive machinery monitoring).

Installation and Maintenance Notes

1. Setup Requirements:
   • Mount the probe using a fixed bracket, ensuring the probe tip is aligned perpendicular to the target surface (maximum angular deviation ≤5° to avoid measurement error).
   • Set the nominal air gap to 1.0 mm (or model-specific value) using a feeler gauge during installation. Adjust the gap to center the probe’s output signal within the linear range of the signal conditioner.
   • Ensure the target (e.g., gear tooth, slotted disk) has a clean, flat surface with no burrs or corrosion, as irregularities can cause signal noise.
2. Wiring Guidelines:
   • Use the provided shielded, twisted-pair cable (3 meters standard) to connect the probe to the signal conditioner. Do not extend the cable without Emerson’s approval, as this may degrade signal quality.
   • Ground the cable shield at the signal conditioner end only to prevent ground loops and electromagnetic interference (EMI) from nearby electrical equipment (e.g., generator exciters).
3. Safety & Troubleshooting:
   • Follow lockout-tagout (LOTO) procedures when installing or servicing the probe—disabling speed monitoring can prevent overspeed protection, risking equipment damage.
   • Common issues and solutions:
     • No Output Signal: Check probe power (via signal conditioner), cable continuity, and target alignment. Verify the target is made of ferromagnetic material.
     • Noisy Signal: Inspect the target for damage/corrosion, re-align the probe to reduce angular deviation, or check for EMI sources (e.g., nearby power cables).
     • Inaccurate Speed Reading: Re-calibrate the signal conditioner’s frequency calculation parameters or adjust the probe air gap to optimize linearity.

Critical Notes

1. Part Number Decoding: The suffix “010-011” in PR9376-010-011 typically indicates specific configurations (e.g., “010” = 1.0 mm nominal gap, “011” = 3-meter cable). Confirm exact specifications with Emerson, as suffixes may vary by region or production batch.
2. Target Design Compatibility: The probe’s performance depends on target geometry (e.g., tooth height, slot width). Refer to EPRO’s target design guidelines to ensure the target is compatible with the PR9376-010-011’s sensing range and frequency capabilities.
3. Genuine Parts Only: Use genuine EPRO PR9376-010-011 probes for safety-critical speed monitoring. Aftermarket alternatives may lack Emerson’s calibration precision or environmental durability, risking unreliable overspeed detection and equipment failure.