LVDT Displacement Sensor DET100A for Lontar power

Date:2025/3/25 8:34:15 Visits: Author:Dongfang YOYIK Engineering Co; Ltd,

LVDT Displacement Sensor DET100A adopts the classic three-coil LVDT structure and realizes the linear conversion of displacement-electrical signal through the principle of electromagnetic induction. Its core components include:

 

​Mechanical structure:

-Coil assembly: The primary coil (1 group) and the secondary coil (2 groups in reverse series) are wound on a high-temperature resistant ceramic frame. The coil uses polyimide insulated copper wire with a temperature resistance of 220°C;

​-Core: Made of high-permeability iron-nickel alloy (Permalloy), gold-plated on the surface to reduce wear, with a travel range of ±50 mm;

​-Housing: 316L stainless steel housing, IP67 protection level, can resist oil mist and steam erosion in the turbine cabin.

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Working principle:

The primary coil is fed with a 1-10 kHz AC excitation signal, the core displacement changes the mutual inductance of the secondary coil, and outputs a differential voltage signal (0-10 V or 4-20 mA). After the signal is linearized by the built-in ASIC chip, the linear accuracy reaches ±0.25% FS.

 

Typical applications in steam turbines

​1. Rotor axial displacement monitoring:

Installed near the thrust bearing of the steam turbine, it monitors the axial movement of the rotor in real time (usually the alarm threshold is set to ±0.5 mm) to prevent friction between the moving and static parts. The temperature compensation algorithm of DET100A can eliminate the ambient temperature drift (≤0.005%/℃) to ensure data reliability under high temperature conditions.

​2. Cylinder expansion difference (expansion difference) measurement:

By arranging DET100A at multiple points (spacing ≤1 m), the thermal expansion difference between the cylinder and the rotor is detected, and the dynamic compensation range is ±20 mm, with an accuracy better than ±0.05 mm, to avoid cylinder deformation caused by thermal stress.

​3. Vibration phase analysis:

Combined with the key phaser signal, the displacement waveform output by DET100A can extract the fault characteristic frequency (0.1X-10X power frequency) of rotor imbalance and misalignment, providing data support for dynamic balancing correction.

 Yoyik can offer many spare parts for power plants as below:

Sensor