Hydraulic motor stroke sensor DEH-LVDT-300-6 is a key sensor for measuring the displacement of the actuator piston in the steam turbine digital electro-hydraulic control system (DEH). It belongs to the linear variable differential transformer (LVDT) type. Its core function is to convert the mechanical displacement of the actuator into an electrical signal and feed it back to the control system to achieve precise adjustment of the steam valve of the steam turbine. It has important application value in power generation, petrochemical and other fields.

Working Principle

The hydraulic motor stroke sensor DEH-LVDT-300-6 is designed based on the principle of electromagnetic induction differential. It consists of a primary coil, two symmetrical secondary coils and a movable iron core. When the iron core moves with the actuator piston, the induced voltage difference of the secondary coil is linearly related to the displacement, and the output signal range is 0.2-4.8VDC (zero voltage 0.2-1.5VDC, full voltage 3.5-4.8VDC). The sensor has non-contact measurement characteristics, avoids mechanical wear, and is suitable for harsh working conditions such as high temperature and vibration.

Application scenarios

1.High-pressure regulating valve control

In large units of 300MW and above, DEH-LVDT-300-6 cooperates with electro-hydraulic servo valves to achieve valve opening accuracy adjustment of ±0.1mm through closed-loop control, and the response time is less than 0.2 seconds.

2. Medium-pressure main steam valve monitoring

Used for switch-type actuators to ensure accurate valve full open/full closed position signals and prevent turbine overspeed or power fluctuations due to displacement deviation.

3. Nuclear power and petrochemical fields

Adapt to fire-resistant fuel oil systems, meet the redundant configuration requirements of API670 standards, and eliminate the risk of false alarms through dual sensors.

Installation and maintenance

1. Mechanical installation

- The coaxiality deviation between the iron core and the measuring rod must be maintained at ≤0.1mm to avoid signal nonlinearity.

- Use M16 stainless steel brackets for fixing, and the bolt tightening status must be checked regularly in a vibrating environment.

2. Electrical commissioning

- Calibrate the zero position (valve fully closed) and full position (valve fully open) to ensure that the output signal matches the physical position.

- Ground the shielded wire at one end, and the distance between the signal line and the power cable is ≥30cm to prevent electromagnetic interference.

3. Environmental adaptability

- Ceramic insulated wires must be used in high-temperature areas. It is recommended to install a heat sink when the long-term operating temperature exceeds 80℃.

The hydraulic motor stroke sensor DEH-LVDT-300-6 has become a core component of modern steam turbine control systems with its non-contact measurement, high precision and strong anti-interference capabilities. Through regular maintenance and standardized installation, the unit regulation stability can be effectively improved and the risk of unplanned downtime can be reduced.

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