【2026 Transmission Equipment】Operation of the barring device during turbine startup and shutdown, as well as emergency measures in case the barring device stops functioning for some reason
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This post was last edited by The one on 2026-5-28 at 14:43. I. Purpose of starting the turning gear before startup: 1. Starting the turning gear upon startup helps to eliminate the non-permanent bending that occurs as a result of the rotor remaining stationary for long periods of time. 2. Preheat the rotor evenly during warm-up to prevent thermal bending. 3. Check the condition of the shafting in advance to determine whether there is static or dynamic friction, as well as any sticking in the shafting. 4. Reduce the starting torque for surge operation. 5. Drain the water accumulated in the cylinder.
II. Purpose of engaging the turning gear during shutdown: 1. To prevent thermal bending of the rotor. During shutdown, the steam accumulated in the cylinder causes the temperature of the upper cylinder to be higher than that of the lower cylinder, resulting in uneven heating or cooling of the rotor and thus bending deformation. 2. Removing the residual steam and water in the cylinder facilitates the drainage of water vapor, preventing water accumulation from corroding components and causing water hammer during the next start-up.
III. Core function of the rotor turning device: The function of this device is to drive the rotor to rotate at a constant low speed, thereby ensuring uniform heating and cooling and preventing the rotor from bending or deforming.
IV. Essential conditions for putting the turning gear into operation There are four conditions that must be met in order to operate the turning gear properly: 1. The lubricating oil pressure must be normal, with the oil temperature controlled between 38 and 45°C, to ensure proper lubrication of the bearing shells； 2. The operating conditions of the generator seal oil system are normal ； 3. The top shaft oil pump is put into operation ； 4. Turn the crank and engage the throttle.
V. Operation procedures for starting and stopping the turning gear (I) Steps to start the turning gear 1. Preliminary checks: Test the light of the turning gear motor and conduct a no-load test to ensure the correct direction of rotation； 2. Manual operation on-site: Ensure that the turning gear is in the disengaged position, activate the solenoid valve for 40 seconds, and the timer will then start the turning gear motor ； 3. On-site verification: The crankshaft rotation indicator light is on, the rated operating speed is 5 r/min, and it is checked that the current during crankshaft rotation is normal.
(II) The turning gear stops normally once the temperature of the stage to be adjusted reaches 150°. Press the stop button on the local control cabinet to cut off the power to the turntable and close the fuel supply valve for the turntable.
(III) Emergency barring – Regular use of the emergency barring system is strictly prohibited! In the event of a failure of the top shaft oil pump, initiating emergency shaft turning will exacerbate wear and damage to the bearing shells; this method should only be used in extreme operating conditions where the rotor is at risk of severe bending.
VI. Precautions for turning the machine by hand 1. Continuous manual turning is strictly prohibited when there is no pressure in the top shaft oil system； 2. Stop the unit by tripping the breaker; the rotor speed must drop to zero before starting the barring gear ； 3. After the unit is started up and its rotor speed exceeds that of the barring gear, the barring gear automatically trips, and the oil supply to it is shut off.
VII. In the event of a shutdown when the cylinder temperature is high and the turning gear stops operating for some reason, what are the emergency response measures? 1. When the turning gear fails and cannot operate, turn the shaft manually. Meanwhile, keep the oil system running continuously. During this period, monitoring of the bearing temperature should be strengthened.
2. If the rotor cannot be rotated due to reasons such as collisions between the moving and stationary parts inside the turbine caused by thermal shock and the resulting deformation, a cylinder sealing procedure should be carried out, and an attempt to rotate the rotor can be made again after 1 hour. Under no circumstances should one attempt to start the machine by feeding steam to the crew or use a crane to force it to rotate.
3. When the turning motor experiences overcurrent, the temperature difference between the upper and lower parts of the cylinder exceeds the specified limit, or when an obvious sound of metal friction is heard, continuous turning should be stopped and regular turning should be adopted instead. Turn the shaft 180° regularly as required. Closely monitor the data in the TSI eccentricity table, and carefully record the eccentricity values, as well as the time and number of disk rotations.