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Quality Steam Turbine Overspeed Trip Device with Mechanical Overspeed Protection 3300 r/min Trip Speed and Interlock Protection factory
Quality Steam Turbine Overspeed Trip Device with Mechanical Overspeed Protection 3300 r/min Trip Speed and Interlock Protection factory

Steam Turbine Overspeed Trip Device with Mechanical Overspeed Protection 3300 r/min Trip Speed and Interlock Protection

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steam turbine components

steam turbine spare parts

steam turbine spares
Product Summary
Steam Turbine Overspeed Trip Device provides mechanical overspeed protection, automatically tripping the unit when speed exceeds 10-12% above rated. It offers interlock protection for vibration, axial displacement, and low oil pressure, plus manual emergency shutdown. Available in weight-type and ring-type designs for reliable, power-independent safety.

Product Details

Highlight:

Mechanical Overspeed Protection Steam Turbine Overspeed Trip Device

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3300 r/min Trip Speed Overspeed Trip Device

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Interlock Protection Turbine Overspeed Protector
Overspeed Trip Threshold: 10%‑12% Above Rated Speed
Example Trip Speed: 3300 R/min
Trip Mechanism Type: Weight-type Or Ring-type
Actuation Force: Centrifugal Force Exceeds Spring Preload
Key Components: Trip Weight, Spring, Adjusting Nut, Striker Pin
Periodic Test Frequency: At Least Once Per Month
Product Description
Steam Turbine Overspeed Trip Device
What is a Steam Turbine Overspeed Trip Device?
Definition

The overspeed trip device is a mechanical overspeed-protection apparatus for steam turbines, serving as a vital actuator terminal for DEH (Digital Electro-Hydraulic Control System) and ETS (Emergency Trip System). Generally mounted at the front end of the turbine rotor or inside the bearing box, it is directly interlocked with the oil-hydraulic control system of main steam valves and control valves.

Core Functions
  • Overspeed protection: Automatically triggers unit trip when rotating speed exceeds 10%-12% above rated speed (e.g. 3300 r/min)
  • Interlock protection: Receives signals of vibration, axial displacement, low oil pressure and other parameters to realize comprehensive emergency shutdown
  • Manual shutdown: Operators can perform emergency trip via handle or push-button
Main Types, Structure and Working Principle

Two widely-used types of overspeed trip devices are listed below:

Weight-type Overspeed Trip Device

Components: Trip weight, spring, adjusting nut, housing, striker pin, etc.

Working Principle:

  • During normal operation, spring force holds the trip weight inside the rotor
  • As rotating speed rises, centrifugal force increases
  • Once centrifugal force exceeds spring preload, the trip weight flies out, strikes the trip lever, actuates the trip oil circuit, closes main steam valves and shuts down the unit

Advantages: Simple construction, reliable performance and power-independent. It acts as the final mechanical protection barrier for the turbine.

Ring-type Overspeed Trip Device

It follows similar operating principle as weight-type version, but adopts an annular mass block sliding axially for triggering action. Mostly applied in large-capacity units with higher sensitivity and smoother actuation.

Key Components and Common Spare Parts
Component Function Precautions
Trip weight / Trip ring Senses centrifugal force to initiate tripping action Smooth surface, free from jamming
Spring Provides preload and sets tripping speed Periodic spring-force test to prevent fatigue failure
Adjusting nut Sets actuation speed No arbitrary adjustment; calibration is mandatory
Striker pin & lever Transmits triggering signal Check flexible inter-linkage movement
Overspeed trip slide valve Controls on-off of safety oil pressure High sealing requirement; oil leakage prevention
Note: Disassembly inspection, cleaning and function test of overspeed trip device shall be completed in every major overhaul to guarantee sensitivity and reliability.
Operation and Maintenance Guidelines
On-site Monitoring
  • Observe status of overspeed-trip indicator lamp
  • Perform reset operation before unit startup
  • Forbid masking or short-circuiting trip signals
Periodic Tests
  • Overspeed test: Mandatory for newly-commissioned units or after major overhaul, to verify actual tripping speed
  • Oil injection test: Available on certain units under running condition, used for checking jamming risk of trip mechanism
  • Manual trip test: Conduct at least once per month to confirm emergency-shutdown function

Mr. Tom Hu

General Manager

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