LVDT sensor DET-150A is a displacement sensor that uses the principle of differential transformer to convert the mechanical quantity of linear movement into electrical quantity. It is widely used in the oil motor stroke monitoring and control of steam turbines.

Product features

• High precision: It can provide sub-micron accuracy and is suitable for measurement occasions requiring extremely high precision.

• Wide linear range: It has a wide linear working range and can meet the measurement needs of different ranges.

• Strong anti-interference ability: Due to the use of electromagnetic induction principle, LVDT sensors have strong resistance to noise and interference in the environment.

• Long service life: The contactless design makes the sensor almost wear-free, thereby greatly extending its service life.

• Simple structure: The product has a simple structure, reliable operation, and easy use and maintenance.

• Good linearity: The linearity can generally reach 0.1%.

• High repeatability: High repeatability, the resolution is generally 0.1µm.

Application in steam turbine

1. Oil motor stroke monitoring:

• Function: LVDT sensor DET-150A is used to measure the stroke of the oil motor of the steam turbine to ensure that the valve opening is controlled within the predetermined range.

• Working principle: When the armature is in the middle position, the output voltage is 0; when the armature moves inside the coil and deviates from the center position, the induced electromotive force generated by the two coils is not equal, and there is a voltage output, and the voltage depends on the size of the displacement.

2. High-pressure valve position feedback:

• Function: LVDT sensor is used to feedback the position of the high-pressure valve to ensure that the valve opening is controlled within the predetermined range and improve the operating safety and efficiency of the steam turbine.

• Working principle: The structure of LVDT consists of an iron core, an armature, a primary coil, and a secondary coil. The primary coil and the secondary coil are distributed on the coil frame, and there is a freely movable rod-shaped armature inside the coil. When the armature is in the middle position, the induced electromotive force generated by the two secondary coils is equal, and the output voltage is 0. When the armature moves inside the coil and deviates from the center position, the induced electromotive force generated by the two coils is not equal, and there is a voltage output, the magnitude of which depends on the magnitude of the displacement.

3. Servo control system:

• Function: In the servo control system of the steam turbine, the LVDT sensor is used to feedback the opening of the regulating valve to ensure the precise control of the valve.

• Working circuit: The working circuit of the LVDT is called a regulating circuit or a signal regulator, which includes a voltage stabilizing circuit, a sine wave generator, a demodulator and an amplifier. The sine wave generator should have a constant amplitude and frequency and is not affected by time and temperature.

4. Fault analysis and processing:

• Common faults: Common faults of LVDT sensors in steam turbines include unreasonable installation, loose local wiring, high ambient temperature, and internal damage to the LVDT.

• Optimization plan: In order to solve the problem of easy breakage of LVDT sensors, a new LVDT installation design plan is adopted, such as a guide rod installed on the LVDT side and two universal joints installed on the connecting crossbar side, to achieve technical measures of “guiding” on the LVDT side and “unloading” on the connecting crossbar side.

The application of LVDT sensor DET-150A in steam turbine has many advantages and functions. It can not only improve the performance and operation safety of steam turbine, but also reduce maintenance costs and extend the service life of equipment.

By the way, we have been supplying spare parts for power plants around the world for 20 years, and we have rich experience and hope to be of service to you. Looking forward to hearing from you. My contact information is as follows:

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