Author: Mohamad Ibrahim, CMRP
|Saudi Aramco’s Sea Water Injection Department has several gas turbines. There is requirement to frequently perform alignment checks in between the turbine rotor and auxiliaries, to avoid defects and equipment damage. The new shaft alignment method uses a slow turning device (electric motor or hydraulic ratchet system) jog push button to simultaneously rotate the combined assembly of turbine rotor accessory gear coupling, the accessory gearbox, and the auxiliary equipment, to perform shaft alignment checks. With this method, the accessory gearbox shaft and auxiliary equipment shafts can be rotated together at the same time, and it becomes possible to use a reverse alignment method with a laser device. This new method does not require disconnecting the coupling between the auxiliary equipment and the accessory gearbox. Before this invention, the couplings had to be removed first, and then the auxiliary equipment was rotated manually. Shaft alignment was then performed by the Face and Rim method, which is time consuming and less accurate. This method has decreased shaft alignment time from several hours to only fraction of an hour. This invention is applicable to all gas turbine models that have a rotor slow turning device (electric motor or hydraulic ratchet system) that can be manually operated by a local control switch or button. This has resulted in an annual cost saving of approximately $180,000.00.