Steps to do Over-speed Test for Main turbine

Steps to do Over-speed Test for Main turbine

 

• Open the Top cover of pilot valves KA02 and KA03 of MAX62AA001 .
• Press the pilot valve KA02 fully and observe the Aux. start-up fluid pressure. lf pressure is ok slowly release the valve.
• Press the pilot valve KA03 fully, to isolate the Auxiliary trip fluid from main trip valve to over-speed trip test device and keep in pressed down till the completion of the test.
• Note down the Aux Trip Fluid Pressure
• Rotate the hand wheel KA01 of over-speed trip test device in clockwise direction for admitting the test fluid to the over speed Bolts.
• The actuation of over speed bolt is indicated on the test rack by lamps for limit switches MAY10CG001 and MAY10CG002, provided on the LHS of front bearing pedestal. Alarm in control room is to be ensured.
• Check whether Auxiliary trip fluid pressure goes to zero.
• Note down the test fluid pressure when over speed bolts acted and ensure alarm in UCB.
• Rotate the hand wheel KA01 of over-speed test unit in the anticlockwise direction where the test fluid gets cut off, to the over speed bolts
• Press the Pilot valve KA02 of over-speed test device, to reset over speed bolts 1 and 2
• Check whether Auxiliary trip fluid pressure builds up and it is as per the recorded value
• Slowly release Pilot valve KA02, of over speed test device. Aux startup fluid Pressure become to zero.
• Repeat last 2 steps to ensure resetting of over-speed trip device bolts.
• Wait for 1-2 minutes (approx.) & allow auxiliary trip fluid pressure to be steady at around 5.0 Kg/cm2.
• Slowly release the knob of pilot valve KA03, of over-speed test device & OBSERVE RISE lN AUX TRIP FLUID
• Press the pilot valve KA03 fully, of over-speed fest device if any drop in Auxiliary trip oil pressure or Load during the releasing of pilot valve KA03.
  
  
  

 

 

 

 

 

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