7400280-110 Proximity Probe Unit

Module Feature

7400280-110 is factory calibrated eddy current proximity probe for turbomachinery protection monitoring system.

It adopts built-in sensing coil and sealed ceramic tip structure, oil and steam resistant, high vibration resistant design for long-term bearing housing installation. It detects clearance between probe tip and metal rotor surface and outputs raw impedance signal to matched proximitor conditioner. It must be used with specified capacitance extension cable and compatible signal conditioner, cannot be replaced arbitrarily. It is stocked as critical maintenance spare for power plant, oil & gas compressor and turbomachinery safety monitoring rack.

Working principle

High-frequency excitation signal from proximitor is transmitted to the internal coil of probe.

Alternating magnetic field induces eddy current on the surface of rotating metal shaft. The coil impedance changes with clearance variation between probe and target shaft. The feedback impedance signal is converted into linear DC gap voltage by conditioning circuit, used for vibration waveform calculation, thrust position monitoring, keyphasor speed capture and DCS alarm interlock.

Onboard components

High-frequency sensing coil, ceramic sensing tip, hermetic stainless steel probe body, internal insulated lead wire, thread mounting stud, sealing and strain relief sleeve.

LED indicators

Not applicable. Probe health condition is judged by gap voltage and fault alarm from matched proximitor module.

Hardware self‑diagnosis

No built-in diagnosis circuit. The supporting proximitor detects probe open circuit, short circuit and abnormal impedance, and uploads fault alarm to monitoring workstation.

Programming softwareSystem dedicated monitoring configuration tool, used for vibration channel setup, gap voltage verification and fault event recording.

Electrical & Process Parameters

Model:7400280-110 Brand:OEM turbomachinery monitoring spare Device type:Eddy current proximity probe Function:Non-contact shaft gap detection for radial vibration, axial thrust and keyphasor speed measurement of rotating equipment

Mechanical & Structure

Mounting:Threaded stud installation on probe bracket Protection class:IP66 after proper installation Housing:Stainless steel probe body + ceramic sensing tip

Environmental

Operating temperature:-40℃ ~ +180℃ Storage temperature:-40℃ ~ +85℃ Ambient humidity:5~95% non‑condensing

Certification:API670 compliant, ATEX optional Status:Original rotating machinery monitoring spare

Installation

Stop rotating equipment before replacement.

Adjust installation gap per drawing requirement, lock probe lock nut securely, avoid pulling and twisting internal lead, test gap voltage and vibration waveform after commissioning.

Interface

Threaded mounting stud, coaxial interface for matched calibrated extension cable.

Diagnostic

Probe fault alarm: Internal coil open/short or coaxial connector contamination and damage. Vibration signal noisy: Shielding failure, ground loop interference or loose locking nut. Gap voltage drift: Shaft surface scratch, dirt accumulated on ceramic tip or improper installation clearance.

Product Brief

7400280-110 proximity probe, eddy current non-contact sensing spare for turbine and centrifugal compressor vibration monitoring system replacement.